Neurotoxic MedicationsThe medications listed below are potentially toxic to CMT patients. Vincristine has been proven hazardous and should be avoided by all CMT patients, including those with no symptoms. Taxols also pose a high risk to people with CMT. The remainder of the medications listed below present varying degrees of potential risk for worsening CMT neuropathy. Before taking any medication or changing medication, all CMT patients should make sure the treating physician is fully aware of their medical condition.
Definite High Risk (including asymptomatic CMT)
- Vinca alkaloids (Vincristine)
- Taxols (paclitaxel, docetaxel, cabazitaxel)
Moderate to Significant Risk
- Amiodarone (Cordarone)
- Arsenic Trioxide (Trisenox)
- Bortezomib (Velcade)
- Brentuximab Vedotin(Adcetris)
- Cetuximab (Erbitux)
- Cisplatin & Oxaliplatin
- Colchicine (extended use)
- Didanosine (ddI, Videx)
- Disulfiram (Antabuse)
- Eribulin (Halaven)
- Gold salts
- Ipilimumab (Yervoy)
- Ixabepilone (Ixempra)
- Leflunomide (Arava)
- Lenalidomide (Revlimid)
- Metronidazole/Misonidazole (extended use)
- Nitrofurantoin (Macrodantin, Furadantin, Macrobid)
- Nitrous oxide (inhalation abuse or Vitamin B12 deficiency)
- Nivolumab (Opdivo)
- Pembrolizumab (Keytruda)
- Perhexiline (not used in U.S.)
- Pomalidomide (Pomalyst)
- Pyridoxine (Although megadoses [10 times or more the RDA] of Vitamin B6 may be harmful, high intakes of vitamin B6 from food sources have not been reported to cause adverse effects.) NIH Fact Sheet
- Stavudine (d4T, Zerit)
- Zalcitabine (ddC, Hivid)
Uncertain or Minor Risk
- Almitrine (not in U.S.)
- Cytarabine (high dose)
- Etoposide (VP-16)
- Isoniazid (INH)
- Lansoprazole (Prevacid)
- Omeprazole (Prilosec)
- Phenytoin (Dilantin)
- Podophyllin resin
- Sertraline (Zoloft)
- Tacrolimus (FK506, ProGraf)
- Zimeldine (not in U.S.)
Negligible or Doubtful Risk
- Cyclosporin A
A Note about AlcoholAlcohol was removed from the neurotoxic drug list in July 2004. While people with CMT generally suffer no ill effects from the moderate consumption of alcohol, they should be particularly mindful of the fact that alcohol affects balance and coordination, and that overconsumption of alcohol is generally not recommend under any circumstances. If you have questions about alcohol and your health, consult your physician.
Neurotoxic Medications and Worsening of NeuropathyThe Charcot-Marie-Tooth Association has long maintained this “Medical Alert” list of potentially neurotoxic medications. It is published on this webpage, in the organization’s quarterly magazine, The CMTA Report, and in a brochure that is distributed along with a “Dear Medical Professional” letter advising physicians treating CMT patients that they should consider the potential risk of prescribing drugs known to have neurotoxic properties. The list is also freely copied and republished.
Click here for an in-depth summary of a study on neurotoxic medications and how they affect CMT patients.
Full Medical Alert Table
The Medical Alert table groups neurotoxic medications by risk category and generic name and provides information about brand names, manufacturers and labeled uses.
It may be downloaded here: Full_Medical_Alert_List.pdf
Medical Alert Card
A printable card may be downloaded here: Medical_Alert_Card.pdf
Dear Medical Professional Letter
The Dear Medical Professional Letter has a brief description of Charcot-Marie-Tooth disease and the neurotoxic drug list. Give a copy to your physician and any other medical professional who is involved in your care and treatment.
Download it here: Dear-Medical-Professional.pdf
Frequently Asked Questions about Medications and CMT
Can dental anesthesia be neurotoxic?
There are no contraindications with dental anesthesia. Nitrous oxide or laughing gas is on our neurotoxic drug list, but this is only considered toxic if the person abuses the drug or has a vitamin B deficiency.
Is Botox for migraine headaches a safe treatment for someone with CMT?
The risk for migraine Botox in CMT is minimal. The symptoms described are well known and common side effects. The treating MD should have mentioned these possibilities. It is unclear if CMT patients are more vulnerable. However, Botox is expected to wear off in 3 months.
Would collagen peptides be harmful for people with CMT who have joint pain?
As far as we know, collagen peptides should not pose a problem.
Which acid reflux medications should I avoid?
Lansoprazole and omeprazole are the only two gastric reflux medications on our neurotoxic drug list and they are associated with neuropathy in only a very small number of patients. Given the widespread usage and rarity of report, the link is tenuous at best. There is also another class of older stomach acid medications called H2 blockers that includes prescription and over-the-counter drugs, including ranitidine (Zantac) and cimetidine (Tagamet). There were a few scattered suspicions with Tagamet but not Zantac.
Prilosec and Prevacid are in a class of medications termed proton pump inhibitors that include some of the following:
- Omeprazole (brand names: Losec, Prilosec, Zegerid, Ocid, Lomac, Omepral, Omez)
- Lansoprazole (brand names: Prevacid, Zoton, Inhibitol, Levant, Lupizole)
- Dexlansoprazole (brand name: Kapidex)
- Esomeprazole (brand names: Nexium, Esotrex)
- Pantoprazole (brand names: Protonix, Somac, Pantoloc, Pantozol, Zurcal, Pan)
- Rabeprazole (brand names: Rabecid, AcipHex, Pariet, Rabeloc)
Is Prilosec contraindicated for people with CMT? The label indicates numbness and tingling as a potential side effect.
Numbness and tingling are listed as side effects for a wide variety of medications, but only a small number have been found to cause or worsen neuropathy. Prilosec has been reported to cause neuropathy and/or myopathy (muscle disease) in a very small number of patients—not enough to know if the effect is real or not. It is not known whether CMT patients are affected differently or why some patients are affected and not others—none of the reported cases were patients with CMT. The related drug lansoprazole was reported in 2005 to cause neuropathy in one patient. This fact should be brought to the attention of your treating physician so a decision on the best course of action can be made.
Will taking steroids help CMT?
Steroids have not shown to be effective in strengthening muscles affected by CMT. Our doctors do not encourage their use.
Prevacid and Prilosec are on the neurotoxic drug list, but Protonix is not on the neurotoxic drug list, even though it is in the same class of drugs. Please explain.
There is very little information about this issue, especially noting the large number of patients taking these drugs. The two mentioned are the only ones reported in the literature, but you are correct to observe that there is no reason why the others should not have a similar risk even though the association has not been noted.
Can people with CMT take AcipHex?
AcipHex (rabeprazole) is in the same class of drug as Prilosec (omeprazole) and Prevacid (lansoprazole), both of which have very rarely been associated with causing peripheral neuropathy. Even this association is still preliminary and not well accepted. I know of no cases associating neuropathy with Aciphex to date, though neuropathy is listed in the company information as a very rare association (less than one in 1,000) from its clinical trials conducted before drug release. It is not known whether AcipHex also carries the same small risk as the other drugs in this class, but it is possible. There is no information on whether CMT patients are at more risk than others. The small risk must be weighed against the drug indication. Definite gastritis or duodenitis is a much stronger reason for use and for potential benefit than simple, uncomplicated heartburn
Can alpha lipoic acid help those with CMT?
Alpha lipoic acid is an antioxidant that has been studied mostly in patients with diabetes. There is some objective evidence that it reduces painful symptoms, but it is not clear if it prevents nerve damage. The agent has not been studied in CMT, to our knowledge, and it is important to know that the mechanisms of nerve injury differ between diabetes and CMT.
Will muscle relaxers affect my CMT?
Muscle relaxers like Soma should not affect your nerves or strength, but may cause sedation or sleepiness.
Is Anavar contraindicated in people with CMT?
To our knowledge, Anavar hasn’t been tested but anabolic steroids are not advised in neuromuscular patients even though they seem like a good idea.
Are any of the ingredients in the sleep aid Ambien harmful to people with CMT?
There is no known link between zolpidem (Ambien) and neuropathy. The drug can cause sleepiness or sedation, which is its primary useful effect and can make some motor tasks more difficult for CMT patients. Anyone who notices a significant decline in strength after taking Ambien should consult his or her physician.
I have CMT. Will Lasik surgery pose a problem?
To our knowledge, people with CMT are at no additional risk in having Lasik or other corrective procedures.
I took Nitrofurantoin (100mg 2Xday) for four days and then realized it was on the neurotoxic drug list. Should I be concerned about worsening CMT symptoms?
Most people don’t have problems with this drug unless they take it for an extended period of at least a month or more. Taking the drug at its usual dose for the typical seven to 10 days rarely causes a problem. I would expect no problems from four days of use.
Is Hepatitis B immunization contraindicated for people with CMT?
Some CMT patients have an autoimmune polyneuropathy in addition to their CMT. For those patients, we must be concerned about vaccinations. Most CMT patients will not have a reaction other than the kind that might be expected in anyone. If the CMT patient has a common reaction to an immunization, the problem will be transitory. However, if the CMT patient has chronic inflammatory neuropathy as well as CMT, the patient could be left with a loss of motor and sensory function. There should not be anything neurotoxic in hepatitis B vaccine; however, there is a protein in some flu vaccines that might produce abnormal response. Unless the patient is hypersensitive or has an autoimmune problem, he/she should be able to tolerate the immunization. For the person who works in a hospital setting, hepatitis might be a real threat. Hepatitis is a far more serious condition than a reaction to the immunization for hepatitis.
Is whooping cough vaccine contraindicated for children with CMT?
Whooping cough vaccine is part of the dPT or dP routine vaccination. It carries no greater risk than any other routine vaccines. I don’t think children or mothers should avoid routine vaccines especially since whooping cough (diphtheria) is trying to make a comeback because of unvaccinated children. Diphtheria infection can cause severe demyelinating neuropathy and is potentially fatal.
Are any vaccines contraindicated for CMT patients?
There is no medical evidence to suggest that any vaccine, including the flu shot, would be inadvisable for a patient on account of his/her CMT.
Are there any contraindications to getting the meningococcal vaccine and the flu vaccine at the same time?
The story of vaccinations and neuropathy is a long and controversial one. In the past, some vaccinations (like swine flu vaccine in the 1970s) prompted concerns about certain vaccines triggering an immune-mediated abrupt neuropathy (Guillain-Barré syndrome) in otherwise normal people. Most associations have not been proved after larger scrutiny. Neither the meningococcal or current flu vaccines are specifically associated with neuropathy but the flu vaccine is different every year. While there is no evidence that vaccines affect the CMT genes directly, the issue has not been studied. When an immune attack on nerves is triggered in a CMT patient, any nerve damage may add to the underlying neuropathy. The process, in general, lasts for one to four weeks and then improves depending on the severity of the process. Guillain-Barré syndrome (GBS) can occur in CMT patients, but there is no consensus on whether the incidence is higher than for the general public. If it does occur, CMT makes the diagnosis more difficult but treatment is the same. It is suspected but unknown whether a mild version of the process commonly occurs because these patients tend not to go to a doctor; however, a mild form of GBS in a patient with underlying neuropathy from CMT could lead to the symptoms presented. Nine days after vaccination is a reasonable time frame but we have no means to prove the association.
What about taking anti-depressant medications?
The risk is minimal if the drugs are indicated. Some of these agents have been studied as treatments for neuropathic pain and showed no signs of making patients worse.
I’m taking medicine for depression. The label says I shouldn’t stop taking it without my doctor’s advice. What could happen?
The major concern about stopping an antidepressant is that you might not be ready to do so. Most doctors recommend that you continue taking an antidepressant for four to six months after you feel better to reduce the risk of your depression returning.
Once you and your doctor decide to stop the medication, the dose should be gradually reduced over a few weeks to avoid the chance of withdrawal symptoms. Some experts recommend tapering the dose down over a period of one week for every month you’ve been on the drug–six to eight weeks if you’ve been on the drug for six to eight months, as a rule of thumb. During this time, you and your doctor should be watching for evidence of withdrawal symptoms or a depression recurrence.
Older antidepressants like tricyclic antidepressants and monoamine oxidase inhibitors have been known to cause discontinuation effects. The most common effects seen in the case of tricyclic antidepressants such as Tofranil and Elavil are upset stomach and nausea, flu-like symptoms, anxiety, low mood, and sleep disturbance. In the case of stopping monoamine oxidase inhibitors, such as Nardil, you may experience disorientation, confusion, mild movement disturbances, and even hallucinations.
It is also becoming increasingly evident that the newer class of antidepressants, called selective serotonin reuptake inhibitors, or SSRIs, such as Paxil and Zoloft, also have discontinuation effects. The most common are dizziness, lightheadedness, weakness, headache, stomach upsets, sleep disturbances, and anxiety. Problems have also been described with some even newer antidepressants, such as Effexor
Is it appropriate to administer a statin-based cholesterol drug with my history of elevated CK’s (generally 350-500 range)?
Mildly increased CK (creatine kinase) values are not a primary reason to withhold a statin drug, but muscle symptoms and CK values should be checked while on the drug. The risk of worsening the neuropathy appears to be very small, but incompletely known, while the benefit of the drugs is well established. Elevated CK levels, in general, are not common with CMT.
Are there any negative side effects to taking Gabitril for a mood disorder with my CMT?
Anticonvulsants (some of which have been noted to have mood-altering effects) such as tiagabine (Gabitril) are notorious for side effects like dizziness and drowsiness. These side effects are also present with conventional antidepressants. CMT patients are, therefore, confronted with a cost-benefit analysis—the feeling of well-being associated with these medications versus the fear of falling down and injuring themselves.
Is creatinine contraindicated with CMT?
I know of no contraindication to creatinine in patients with CMT.
I am interested in learning more about the CMT neurotoxic drug list. Why is a drug placed on the list? What is a mega dose? Regarding pyridoxine (Vitamin B6), should we avoid multivitamins with B6?
The neurotoxic drug list was compiled by neurologists and is continually monitored for additions and corrections. A mega dose is defined as 10 times the RDA (recommended daily allowance). A daily multivitamin capsule should not be a problem.
Are statin drugs safe for people with CMT?
The statin drugs are safe for most patients with CMT. The muscle weakness that they can cause is not an issue for most of the people who take them. The CMT doctors all agree that it is more important to control high cholesterol than to worry about possible muscle weakness.
Why are certain drugs considered neurotoxic for CMT patients? Is there general knowledge of what happens when these items are ingested by someone with CMT?
Neurotoxicity is the capacity of chemical or biologic agents to induce functional or structural changes in the nervous system resulting in tissue injury. There are many substances that produce damage to normal peripheral nerves, including heavy metals such as lead, arsenic, mercury and thallium, and drugs such as vincristine, thalidomide and pyridoxine. The mechanism in each of these substances is different and in some of them, the exact mechanism is unknown. If these substances damage normal nerves, patients who already have a nerve disease, either hereditary as in CMT or acquired in diabetes, are more susceptible to these substances. The more severe the neuropathy, the more susceptible the patient to the exposure of the neurotoxin.
Is it okay for someone who has CMT Type II to use Mycolog II Cream (Nystatin and Triamcinolone Acetonide cream) for dermatologic use?
There would seem to be no problem with the topical application of Mycolog II cream. I am aware of only one reference to peripheral nervous system toxicity and topical creams/ointments. A 30-year-old African woman sustained weakness in her legs and a burning sensation in her feet for two months following the application of hydroquinone (skin bleaching) cream, which she had been using for four years. Her symptoms dissipated in four months.
Is there a cholesterol medication that people with CMT can take?
There are many medications that reduce serum cholesterol levels, but the “statins” are the most effective and most widely used. The current evidence suggests that statins rarely cause myopathy or neuropathy. Given the health benefits of reducing high cholesterol levels, and the rarity of these (and other) side effects, statins remain the drugs of choice for treating high cholesterol levels. It is a theoretical issue whether patients with CMT should avoid statins, as there is no evidence that statins worsen existing neuropathy.
You have statins listed on your general drug list, and you have several specific statins listed on your expanded drug table, but rosuvastatin (Crestor) is not listed. Should it also be on the list?
There is no evidence that one statin is any better or worse as a risk factor for neuropathy, so Crestor is part of the group even without a clearly reported case. However, the effect with all of the statins is rare and we are not advising patients to avoid statins, only to be aware of the association. Statins are clearly superior to the older treatments for hyperlipidemia (elevated cholesterol levels), so each treating physician needs to weigh the clear benefits of the drugs against this small risk in CMT patients.
Are Premarin or Fosamax. contraindicated for those with CMT?.
There is no listed contraindication to the use of alendronate (Fosamax) in patients with CMT. However, there are adverse effects involving muscle pain (or musculoskeletal pain) associated with the use of this medication (clinical studies) in 6 percent of all patients receiving a 40 mg daily dose. This adverse effect usually doesn’t result in discontinuation of the alendronate.
Would you please comment on the possible neurotoxic effect of Tylenol, aspirin, and Advil as over-the-counter pain relievers for CMT patients?
There are no reported contraindications for persons with peripheral neuropathies taking these over-the-counter drugs.
Will estrogen for osteoporosis cause my CMT to worsen?
I have not encountered any problems with CMT patients taking hormone therapy of estrogens or progesterone. Neither do I believe that there is any theoretical reason why this should make a neuropathy worse. If there is any deterioration of your CMT, you should be evaluated immediately, but I would not expect that to happen and believe you should take the advice of your doctor.
What are your thoughts on Tymlos for osteoporosis in a person with CMT?
As far as we know, there should not be any neuropathy concerns with this medication. However, there are other unrelated risks that the patient should discuss with the prescribing MD.
Have there been any studies on the effect of L-histidine on CMT patients?
L-histidine is an essential amino acid that is supplied in adequate amounts in any good diet. To my knowledge, there are no studies using L-histidine in patients with neuropathies and none in hereditary neuropathies. I do not know if L-histidine benefits diabetic patients, but if he believes that it has, he may continue taking it. Diabetes mellitus produces different types of peripheral neuropathies. Some of these are very serious. Your son has two diseases that independently affect the peripheral nerves and in combination can aggravate the nerve damage.
The genetic defects in most demyelinating types of CMT are known, as are the encoded proteins and their functions. However, at the present time there is no effective treatment to stop or slow down the progression of the disease and we do not yet know how to regulate or replace the myelin proteins. Your son needs the advice of an internist to keep his diabetes under control. He also needs the advice of a neurologist regarding the CMT. A good occupational therapist may recommend some tools to facilitate hand and finger use.
Do beta blockers like atenolol have adverse side-effects on CMT patients?
Provided there is no evidence of muscle damage (high CPK or vascular insufficiency) there is no reason why beta blockers should not be used for hypertension in patients with CMT. The cardiologist should be aware of any EKG changes.
Have there been any studies on the benefits of Neurontin for people with CMT?
Neurontin is one of a group of medications that are used to treat painful peripheral neuropathies. As with the other medications utilized for this “neuropathic pain,” including amitryptiline, nortryptiline and carbamazepine, Neurontin is not specific for CMT pain, but is used in many painful neuropathies. Unfortunately, none of these medications work all the time for all patients; some work for some patients, others work for other patients. It is not easy to predict which medication will work for which patient in advance. While there are thoughts on how some of these medications work, how Neurontin stops pain is not clear. Of interest is the fact that other anti-seizure medications, like phenytoin (Dilantin) or carbamazepine (Tegretol) also treat pain in some patients with neuropathy.
I will be given Versed for a colonoscopy. Is this problematic?
Midazolam (Versed) is a medication used to assist in the sedation, reduction in anxiety, and impairment of memory in patients undergoing procedures (including endoscopies). Some medications have so-called “black box warnings,” meaning that past experiences dictate caution in their use because of significant adverse reactions. Midazolam has a black box warning stating: “Midazolam I.V. has been associated with respiratory depression and respiratory arrest. In some cases, where this was not recognized promptly and treated effectively, death or hypoxic encephalopathy resulted. Use Midazolam I.V. only in hospital or ambulatory care settings, including physicians’ offices, that provide for continuous availability of resuscitative drugs and equipment and personnel trained in their use….” This would apply to any patient. Overdosing of Midazolam may be a concern in CMT patients and it sounds to me that since you have undergone this procedure before without the use of Midazolam, it would be safer to do the same thing again.
Are people with CMT prone to reactions from anesthesia when having surgery?
Most people with CMT will have no problem with anesthesia. Only those with respiratory involvement (very rare) or vocal cord paralysis (a very rare variant) may have problems with anesthesia above that seen in the general population.
I am scheduled to undergo a colonoscopy, and I am told that a type of nuclear medicine will be used during the procedure. Are nuclear medicines dangerous for someone with CMT?
It depends on which nuclear medicines are used. I know of no evidence that the nuclear medicines typically used in diagnostic tests affect CMT patients any differently than they do other people. Nuclear medicines and radiation treatments used against cancers are in a different category, but the drugs generally used in colonoscopy are light anesthetics. None of these drugs, such as midazolam (Versed), are on the list of agents with increased risk.
My doctor has informed me that he will administer Propofol during my colonoscopy. Do I have any cause for concern?
No. I am not aware of any problem with Propofol as an anesthetic in CMT patients. There are concerns for prolonged general anesthesia in the ICU setting for many days to weeks, but there is no evidence of a problem with short-term anesthesia.
I am taking biotin because I have brittle nails, but I am concerned because it is listed as B-complex. Can biotin have an adverse effect on CMT?
There is no known association between biotin and neuropathy. The only B-vitamin clearly known to cause neuropathy from excessive use is pyridoxine (B6). However, all vitamins should be taken in conventional doses unless otherwise directed.
Can I take Coumadin if I have CMT?
Many people take the blood thinner warfarin (Coumadin) for a variety of reasons. The drug interferes with blood concentrations of many other drugs and this fact needs to be taken into consideration when dosing, but there are no suspicions that it causes neuropathy or worsens CMT.
Can you tell me if Macrodantin can adversely affect CMT patients?
Nitrofurantoin (Macrodantin) is an antibiotic used for a variety of problems, but more extensively in past decades for UTIs. It is associated with causing and worsening neuropathy, especially if taken on an ongoing basis; however, the nerves that control respiration are not usually involved especially if the nerves to the limbs are not similarly affected. There is surprisingly little information about CMT patients using this drug on a regular basis. The drug, however, is associated with other direct lung (pulmonary) toxicity of differing types and is more than likely the cause of your problem.
Is the use of Androderm advised or not?
Male and female steroids (hormones) of various types appear to affect a variety of normal nerve and muscle functions. Treatment with onapristone, a progesterone antagonist, has improved the neuropathy of the CMT1A rat, but has not been tested in humans yet. Testosterone (Androderm) has beneficial effects on muscle building, but also has numerous deleterious effects, including those on prostate tissue. The changes described are not surprising following the loss of the hormone treatment, but testosterone has not been adequately examined for safety and efficacy in CMT patients to recommend use for neuropathy. However, it is not something to avoid in a CMT patient, if indicated for another condition. As with any treatment with possible toxicity, the relative risks and benefits need to be weighed. The potential benefit may simply be adding more muscle and not improved nerve function.
Is there any reason for me to be concerned about taking prednisone?
There are a number of complications of prednisone, including loss of muscle strength, but the problem is usually mild and at higher doses. The effects are uncommon and directed directly against muscle and not on the nerve or worsening of CMT. The effect is likely magnified with already weak or inactive muscles. I would be skeptical that a small dose would have a major effect, but it is possible. Decisions about steroid use or dose should be weighed against the expected benefit gained for the arthritis and the severity and type of the arthritis.
Will Adriamycin worsen my CMT?
Adriamycin is occasionally reported to cause neuropathy, but not with the frequency or severity of some other chemotherapy drugs such as vincristine, Cisplatin, suramin, and taxol. A recent in-depth literature review found no cases going back to 1963 that described any effects, positive or negative, of Adriamycin in a CMT patient. The agent was placed on the list based on the experience with other types of patients receiving the drug as part of their chemotherapy. In addition, most of the literature on other medications is based on patients with CMT1A (the commonest demyelinating form). We know very little about special risks for patients with less common forms of the disease.
Can Lamisil cause my CMT to get worse?
There are no known reports of terbinafine (Lamisil) causing peripheral neuropathy or worsening CMT-related weakness. I performed a brief literature review and checked the manufacturer information to confirm this fact. A recent review of the North American CMT database uncovered no cases of terbinafine complications, but it may be that no patient reported using the medication. Rash, however, is a potential complication of any medication. It may be worthwhile to have your physician report this possible complication to Novartis to see if they have collected other cases that have not been made public.
I am bi-polar and take 1800mg of Eskalith (lithium carbonate) a day. I was diagnosed with CMT in 1999 and since then I have developed a problem with severe shaking, as if I were really cold. I would appreciate any information you can give me about this.
Tremor is one of the more common side effects of lithium. I would theorize that CMT would enhance this effect but I am not aware of any association between the two. The tremor is not a permanent effect or a sign of your neuropathy worsening, but you should discuss the problem with your psychiatrist to confirm this suspicion and weigh your options, depending on how bothersome the shaking is to you.
Should either Reglan or Lomotil (diphenoxylate/atropine) for ulcerative colitis be on the CMT neurotoxic list?
There is no known or reported link between worsening neuropathy and either Lomotril or metoclopramide (Reglan). Reglan is associated with other neurological side effects, most commonly movement disorders, which are usually recognizable by treating physicians. Some forms affect muscle tone (dystonia), which can disrupt balance, especially if it is abnormal at the outset. It is difficult to sort out which effect is at work in this instance.
Is a 30-day dosage of oral antibiotics okay for CMT patients?
Taking antibiotics for a prolonged period sometimes puts one at different risks than the usual five- to 14-day course prescribed for most infections. Usually this implies that the underlying infection is more severe or more difficult to eliminate. Only a few antibiotics are known to be of higher risk to CMT patients than others, so I would need to know the specific antibiotic to answer fully. The two used for bacterial infections with the most convincing link to neuropathy are metronidazole (Flagyl) and nitrofurantoin (Macrodantin, Furadantin, Macrobid). Others used for viral infections (HIV agents, wart virus) fungal infections (griseofulvin), and parasitic infections (malaria) are usually considered separately. There are a few others with minor or preventable risk, such as Isoniazid (INH). Most antibiotics in common use are not associated with neuropathy, even with prolonged use.
I have CMT. Are progesterone or Serafem safe for me to take?
This is a complex situation. The effects of progesterone on CMT1A are still investigational. All of the data that I’m aware of is from laboratory cultures or rat nerves and models, not humans. Progesterone is involved with nerve function and one progesterone blocker (onapristone) is a source of interest for a treatment trial because of its beneficial effects on a rat model of CMT1A, but the issue is far from settled. These theoretical and laboratory tests must be weighed against your current hot flashes and related symptoms. I believe there are HRT formulations with lower progesterone content, but someone expert in that area would need to advise you on which formulation is most appropriate and the lowest risk for non-neurologic complications, such as endometrial hyperplasia.
The degree of interference with your normal life and duties are important considerations. In other words, the evidence is not established that progesterone is directly harmful, but the laboratory evidence is suggestive and needs more study. I do not know of any documented case of someone’s CMT worsening because of birth control pills or HRT.
Serafem is a completely different type of agent and is the same chemical as Prozac (fluoxetine). I do not know the literature well, but do not think the success with these types of agents has been terrific in treating perimenopausal symptoms, though the risk of trying is low. The only agent in that group that has been questioned about a detrimental effect on CMT is Paxil (paroxetine).
I have a prescription for Metanx, which includes 25 mg of pyridoxal 5’-phosphate (B6). Is that a problem?
>A dose of 25 mg/day of pyridoxine appears to be of negligible risk. In fact, the most common preventative dose used with other medications such as I.N.H. is 50 mg/day. Most toxic exposures are from much higher dosages, mostly of 250 mg or more a day. Doses in excess of 50 mg/day are unlikely of added benefit to CMT patients
Do you know if Metanx has any withdrawal effects?
The formulation is actually a collection of vitamins intended for patients with high homocysteine levels, an independent risk factor for heart disease and stroke. Most people with this risk take daily folic acid supplements and this formulation appears to be an attempt to supply a more complete but unproven formulation. The benefit is not intended to treat cholesterol per se. The vitamins included are folate, vitamin B6 and vitamin B12, which qualifies the pill as a food supplement and not a drug. The amount of B6 is small as long as multiple pills are not used daily. There is no risk of withdrawal effects and the skin rash described is more indicative of a drug allergy or a separate viral illness, but a physician should examine the rash to be sure. Novocaine allergy is extraordinarily rare.
Has there been any investigation regarding the use of methylcobalamin in treating people with CMT?
There has been considerable research on vitamin B12 and some forms of B12 such as methylcobalamin and neurologic function. More importantly, B12 levels and other related B12 functions are frequently checked because low levels can result in a variety of neurologic problems, including neuropathy. The main benefit is for patients with deficient or low vitamin levels. The benefit to patients with normal vitamin levels and function has not been established. I am not aware of attempts to treat otherwise normal CMT patients successfully with B12, but it has been tried in diabetic neuropathy without clear benefit in patients with normal vitamin levels. On the other hand, if there is any doubt when measured vitamin levels are borderline, methylcobalamin is safe in reasonable doses.
I have CMT and diabetes and have been on kidney dialysis. I am going to have a kidney transplant soon and would like to know if the drugs are going to affect my CMT?
The issue is complex because CMT, kidney failure and diabetes can each cause neuropathy. There are a few drugs that rarely cause neuropathy, but there is not enough experience to recommend avoidance or a special susceptibility by CMT patients. The first is tacrolimus (FK-506, ProGraf), which rarely causes a neuropathy with demyelinating features, probably by triggering an immune reaction. The drug is also under investigation for supporting nerve growth. The vast majority of patients have no problems with neuropathy on this drug, but if you use it, the degree of neuropathy-related weakness should be monitored. Cyclosporin A can cause the same problem, but even more rarely. However, immunosuppression is a required treatment in order to prevent rejection of the transplant, so the issue and relative risks and benefits should be discussed with your local physicians. This is probably an example where the benefit is great and the risk is small.
I have CMT and was prescribed Amerge 2.5. I experienced severe cramps in my lower extremities and could not move my lower legs. Are those side effects related to the medication?
Naratriptan (Amerge) is a commonly prescribed migraine treatment in the triptan class and is similar to Imitrex (sumatriptan). Both may have a variety of side effects, which are complicated by the fact that most who take the pill already suffer from an acute migraine. Common and infrequent reactions include nausea, odd numbness, chest tightness, dizziness, drowsiness, and fatigue. There is no evidence, however, of true worsening of weakness or sensory function. Muscle cramps are rarely seen, but could be more common in patients prone to cramps, such as patients with CMT.
I am taking Zetia to lower cholesterol. Is Zetia contraindicated for people with CMT?
Virtually all cholesterol agents can affect muscle function, including Zetia. Ezetimibe (Zetia) is the first of a new class of antihyperlipidemic agents, the cholesterol-absorption inhibitors. It is known that most lipid-lowering therapies, including statins, fibrates, and niacin, may cause muscle toxicity and Ezetimibe is touted as an alternative. Studies by the manufacturer did not seem to uncover cases of muscle problems, but there are now a handful of reports, though not well-documented, with this drug as well. Some theorize that drugs that interfere with fat metabolism may disrupt normal muscle function in a small percentage of patients ranging from one in a 100 to one in 1,000, depending on the agent.
Given the current knowledge, this drug is still probably a good bet if lipid therapy is needed. The combination of this drug and a statin may have added toxicity but this fact is not well established. There is no known link between this drug and neuropathy or a specific link to CMT, though any cause of muscle weakness can hamper function in CMT patients who have weakness as part of their condition. Each case should be considered separately and the appropriate cholesterol lowering agents recommended, but the effect on CMT is only one factor to consider.
Zetia can cause toxicity to the liver, especially in patients that already have liver problems, such as chronic hepatitis C. An internist or gastroenterologist would be better to consult about these hepatic (liver) issues. I do not know the relative risk in this setting that appears to be separate from CMT
Is there any information on the osteoporosis drug Evista (Raloxifene HCI) and its side effects on persons with CMT?
There is no known direct effect of Evista on CMT patients or peripheral neuropathy. However, deep venous thromboembolism (DVT) is one rare but potential side effect of the treatment. CMT patients with severe weakness, especially those who are wheelchair bound with limited leg movement may be at higher risk and should discuss the treatment with their physician to see if other precautions or preventative treatments are needed.
I am treating a 20-year-old patient with leukemia. After his fourth dose of vincristine, he had progressive, severe neuropathy in all extremities, dysphagia and dysarthria. EMG studies are consistent with CMT. Now he needs additional chemotherapy. Can you give me any additional information as to why Adriamycin is in the uncertain category? Have any patients received high-dose cytarabine?
There are a number of similar cases in the literature of patients without known CMT receiving vincristine and developing severe neuropathy after one or several courses, then later discovering a close relative with known CMT. The association seems to hold true only for CMT1A, the most common form, and HNPP (Hereditary Neuropathy with liability to Pressure Palsies); both are associated with defects in the PMP22 gene. Vincristine in particular is an exceptionally high risk for CMT1A patients and can result in severe, irreversible neuropathy after one or two standard doses. If your patient has another form of CMT, then the case is reportable.
Other drugs on the medication list have less clear associations with CMT and excessive toxicity. Most seem to carry similar risk to others with neuropathy from other causes–diabetes, etc. Both Adriamycin and high-dose cytarabine carry possible but much less risk than certain agents better known to cause neuropathy such as platins, taxanes, thalidomide, suramin, and Velcade (bortezomib). The small risk of the agents you mention is based solely on small numbers of possible or probable but not definitive case reports in cancer patients; no reports of use of these agents in CMT patients is known. This small risk should be weighed against the potential benefits of additional chemotherapy.
My husband has CMT and hepatitis C. He has been on Pegasys and Copegasys for 10 weeks now. I think that the effects he feels are more severe than what other people experience. Are there any studies on treating patients with both conditions?
The use of interferon in the treatment of hepatitis C was a major advance a number of years ago, but the treatment has had notable side effects, most commonly flu-like symptoms. There is no clear indication that Peginterferon alfa-2a (Pegasys) can independently cause peripheral neuropathy or worsen CMT-related weakness. The only notable interaction is with the treatment and certain HIV-drugs, which I presume are not an issue. Hepatitis-C infection is a much more common cause of neuropathy and one important reason to suppress the virus. The treatment is rarely associated with certain eye and retinal problems that are not at issue in the most common forms of CMT.
Is there any reason why a CMT patient should not take Humira for rheumatoid arthritis?
Adalimumab (Humira) is a recombinant human IgG1 monoclonal antibody that blocks the action of human tumor necrosis factor (TNF), which is thought to be a factor in the joint inflammation in rheumatoid arthritis. This is an emerging and exciting new class of drugs used to treat several autoimmune diseases. Others in this class of drugs, termed TNF-alpha blockers, but not this particular agent, have very rarely been associated with triggering other autoimmune disorders, including demyelinating neuropathy in a handful of instances.
Patients with these other, similar treatments (three in total at this point) have developed otherwise typical chronic inflammatory demyelinating neuropathy (CIDP), an acquired disease that affects many of the same nerve fiber types as CMT. There is no information about a positive or negative reaction from a patient with CMT with any of these treatments. The risk is quite small but should be weighed against the severity of the arthritis being treated.
I have just been prescribed Inderal LA 80 for severe hand tremors. Will this work or have any effect on the CMT?
Inderal is not associated with causing or worsening neuropathy or CMT. It has many uses including blood pressure control, heart disease, migraine prevention, and suppressing essential tremors. The chance of it working depends in part on the type of tremor and whether it is part of the CMT1X or a separate problem. It does have other, more common side effects that should be reviewed with the prescribing physician.
Do Lupron Depot 3.75 mg injections (1x/month) cause any known problems with CMT patients?
>Lupron is not associated with worsening CMT or causing neuropathy, but what happens when sex hormones are altered in people who have disorders with muscle weakness, including CMT, is a very active area of current research. No recognized treatments or precautions have yet been accepted. Lupron suppresses testosterone levels in both men and women, which is an important factor in muscle bulk. None of the other medications listed are associated with weakness or neuropathy, but your case sounds more complex than many because of the antiphospholipid syndrome.
A lot has been written recently about lawsuits against suggesting that Lipitor causes peripheral neuropathy. Do you think this is a problem that CMT patients should consider?
This topic is quite controversial. Over the years, there have been a handful of single cases suggesting that Lipitor or other statins caused neuropathy, but no one thought the issue was very important. This new round of concern is based on a single large study in Denmark that found that people who had neuropathy with no known cause were more likely to be taking a statin. Others have argued that they could not be sure that there were no other explanations for these neuropathy cases, such as metabolic syndromes or mild diabetes. The statins are on the CMTA’s drug list, but I think that people with CMT and high cholesterol would be negatively affected by avoiding Lipitor or other statins if they truly need them. If they appear to worsen after starting a statin, the issue should be addressed with their physician. Of course, if they don’t actually need the statin, they should think carefully before using one. Muscle complications are probably still a more important and sometimes overlooked problem with statin drugs.
I was just diagnosed with macular degeneration. The specialist told me there is a new treatment in which the cancer drug Avastin is injected into the eye. Will this worsen my CMT?
The new and promising drug Avastin (bevacizumab) is not known to cause or worsen neuropathy, but the drug has not been in use very long. Many of the cancer trials used the drug in combination with other chemotherapy drugs that often cause neuropathy, but studies did not find a further increase with the Avastin. There are no reports of neuropathy and Avastin in association with macular degeneration applications.
Can I have Versed before surgery?
I know of no special concerns with Versed and CMT unless it is used for an extended period of time, unlike the brief exposure for anesthesia before surgery.
I have been taking the anti-fungal drug Nystatin for years to control Meniere’s disease. Is Nystatin a member of the statin family or is it just an accident of name?
Because of the addition of so many new medicines over recent years, name similarities are inevitable. The statin class of cholesterol drugs inhibits a critical enzyme in cholesterol production. Nystatin is a completely unrelated antibiotic drug that long predates statin cholesterol drugs and is primarily used to treat fungal infections; Nystatin is NOT associated with neuropathy.
Is there any reason why a patient with CMT should not take antimuscarinics such as Vesicare to treat overactive bladder?
Antimuscarinic medications such as Vesicare are not known to cause or worsen neuropathy. Other types of neuropathy, especially from diabetes, often impair autonomic nerve fibers and these types of drugs can cause an exaggeration of some expected and predictable side effects such as dry eyes and mouth; however, most CMT patients have minimal or no autonomic impairment and they should not have concerns any different from any other patient without CMT.
Is Focalin XR, 20 mg contraindicated with CMT?
Dexmethylpenidate (Focalin), approved in 2001, is chemically similar to Ritalin, a drug familiar to many. X-linked type CMT 2 is an unusual form; CNS demyelination is also seen, but is unusual as well. This class of medication is not known to affect CMT or cause neuropathy and is not contraindicated in CMT in general. It can decrease appetite and lead to weight loss. It may also enhance the risk of seizures in susceptible individuals.
Can a person with CMT get the shingles vaccine Zostavax?
>While Zostavax, intended for adults over 60, has been approved by the FDA, there is still somewhat limited experience with it. However, results published in the New England Journal of Medicine are very promising. The vaccine was studied in about 38,500 adults, half of whom received the vaccine; the subjects were followed for an average of 3 years. Subjects who received the vaccine were half as likely to get shingles (herpes zoster) and much less likely to develop postherpetic neuralgia (PHN), the painful form of neuropathy limited to the region of the shingles. It appears that everyone who developed PHN actually had true shingles, despite the vaccine and not because of a vaccine reaction. There is no evidence that CMT patients would fare differently from others and PHN can be particularly painful for these individuals. There is no mention of whether any CMT patients were included in this large trial.
Is Effexor safe for a person diagnosed with CMT?
Venlafaxine (Effexor) is a popular and widely used antidepressant that is also used to treat neuropathic pain, especially well studied in patients with diabetic neuropathy, although the drug has no current specific FDA indication for this use. It has not been associated with worsening CMT neuropathy. The drug does have a variety of side effects and unusual complications that should be considered before use or withdrawal of use. The drug appears to have an increased risk of neuroleptic malignant syndrome and possibly serotonin syndrome, emergent conditions that affect muscle, but this risk is not further increased, to my knowledge, by having CMT.
Is the combination of verapamil and Avapro as blood pressure medications considered neurotoxic? I take the above medications and my symptoms appear to be worse.
>I know of no evidence that either of those drugs produces worsening of neuropathy either alone or in combination.
I am currently taking Klonopin and Cymbalta. Are these okay to take with CMT?
Cymbalta (duloxetine) is one of the few medications that went through the lengthy process to receive FDA approval for neuropathic pain, specifically for diabetic neuropathy, but is generally used for any type of neuropathy-associated pain. The drug was approved in 2004, so it has quite a while to go before legal generics can be sold in the US. Duloxetine is an anti-depressant and not a benzodiazepine, but the drug has been studied to treat anxiety as well. Klonopin is a benzodiazepine.
My doctor has me on 20 mg of methadone for long-acting pain relief and Vicodin for breakthrough pain. I also take Valium for anxiety. Could these medications be making my CMT progress, and how safe are narcotic treatments for long-term use? I have tried Neurontin with little or no relief.
Contrary to public opinion, except in the case of over dosage, oral narcotics such as methadone are some of the safer medications in use. I know of no evidence linking their use to worsening or causing neuropathy, abnormal muscle cramps or muscle spasm; however, the timing raises the question in this case. Your physician is correct that too rapid a withdrawal can cause unpleasant symptoms. Intravenous heroin has very rarely been linked to nerve injury, but almost certainly because of toxic and unintended side products in the injections used by some addicts. Methadone and Vicoden pills have no such concerns.
Certainly, the underlying problems of CMT, Charcot joint, arthritis and spine disease must also be considered by your physician. Simple carpal tunnel syndrome is common and treatable in patients with neuropathy of any cause, including CMT. There are other medications not mentioned that can possibly cause the described symptoms, especially certain nausea medications and some others. Having your physician see the clawing and examining the hand is needed for specific recommendations, but the narcotics would be a highly unlikely underlying cause.
Is vincristine related to vinblastine?
Vinblastine is closely related to vincristine. Although there are no specific reports of vinblastine toxicity in CMT, it likely is a very high risk agent, especially if the man has CMT1A. Vinblastine also causes neuropathy in individuals without existing neuropathy. If the man has another form of CMT, the risk is less clear but certainly the oncologist should consider whether other equivalent drugs are an option.
Are there nutritional supplements and/or herbal supplements that should be avoided by a person with CMT? Can increased doses of magnesium citrate cause neurotoxicity?
There is very limited information about nutritional and dietary supplements and peripheral neuropathy. I know of no suspicious or theoretical problems with magnesium citrate or calcium lactate. There were a few reports of sudden neuropathy with St. John’s Wort in the late 90s, but very little since then. Podophyllin resin is clearly neurotoxic and is contained in certain roots used in Chinese herbal remedies, but it hasn’t been used in Western supplements since the 1980s. One problem is that the full ingredient list in some herbal supplements is not available, accurate or required.
I experienced a lot of side effects when taking amitriptyline. Is this normal?
The painful reaction experienced is a very unusual reaction to amitriptyline (Elavil). The drug is on the negligible list only because of some very old and unconvincing reports from the 1970s. There are other common side effects attributable to predictable blocking of autonomic nerve signals that cause dry eyes and mouth and bladder complaints; increased pain and weakness are not typical side effects. Drowsiness is also common. The drug is still frequently used to treat the symptoms of neuropathy as long as the common side effects are tolerable; there are other similar drugs available with fewer side effects. However, the drug appears to be intolerable to this patient and probably best avoided. I have found no other similar reports of this kind in a review of the North American CMT database registry.
Do you have any information about Arimidex and CMT patients?
There is no known effect on CMT or neuropathy from Arimidex or similar breast cancer hormone treatments. There are some possible beneficial effects of some other hormone blockers, especially progesterone blockers, in animal models of CMT1 and this question is an active line of research, but the effects from Arimidex are likely to be clinically insignificant; the drug has demonstrated benefits in the proper breast cancer setting.
Is Vitamin D helpful for people with CMT?
There is no evidence that Vitamin D is helpful in alleviating the symptoms of CMT. However, if you are Vitamin D deficient, discuss supplementation with your doctor.
Has Botox been used in CMT to release hammertoes, Achilles tendons or anything else?
Dr. Greg Stilwell responds: “Botox has been used successfully in spastic contractures, as well as hyperhidrosis (sweaty feet). Typically, spastic contractures are NOT seen in CMT, but a podiatrist/orthopedist or physiatrist well versed in CMT could evaluate that individually. The hammertoes seen in CMT are usually as a result of muscle imbalance and structural misalignment. The most successful reports of Botox have indeed been in the Achilles tendon; these are usually cases where someone has had a stroke or other central nervous system insult that results in spastic contracture of the Achilles.”
Do vitamins help with CMT?
As far as we know, there are no specific vitamins that help with CMT.
I have CMT and would like to know if it’s okay to take vitamin B12 and B complex vitamins?
Other than B6, the B vitamins have no known risk. One should avoid megadoses of B6 (10 times the RDA), which presents a danger only when taken in excess of the supplemental. Additionally, taking megadoses of any substances is not advisable.
Are Lidocaine injections with epinephrine safe for CMT patients?
I am having some facial work done. Is hyaluronic acid okay?
What anesthetics should be avoided?
There are no contraindications for anesthesia. The only thing to be aware of and to tell the doctors about is that you will not recover from anesthesia as quickly as a person without CMT, so they need to take their time in moving you.
Alcohol used to be on the neurotoxic medication list. Will drinking alcohol make my CMT worse?
Alcohol was removed from the neurotoxic drug list in July 2004. While people with CMT generally suffer no ill effects from the moderate consumption of alcohol, they should be particularly mindful of the fact that alcohol affects balance and coordination and that overconsumption of alcohol is generally not recommended under any circumstances. If you have questions about alcohol and your health, consult your physician.
The CMTA website lists Metronidazole (Flagyl) as a neurotoxin with “moderate to significant risk (extended use)” for individuals with CMT. What length of time constitutes “extended use?”
There is no hard and fast rule that determines extended use, but it is usually many weeks to several months. Most Metronidazole (Flagyl) treatments are 2 weeks or less and constitute very limited risk. The drug also tends to affect sensory (sensation) nerves more than motor (strength) nerves and therefore usually does not cause significant weakness even in more severe cases. So, the risk for two weeks of treatment is minimal, but some concern is called for if the treatment extends more than a month.
Is Botox a safe and efficient treatment for people with CMT?
According to our CMT experts, Botox is not recommended for individuals with CMT but can be used in areas that are not directly affected by CMT (the face, for example).
Will cosmetic botex injections (face) worsen my CMT?
Botulinum toxin (Botox) is complicated for CMT patients. In most instances any weakness produced should be very local to the injection site and temporary. There is some evidence but not a well-accepted belief of mild effects on muscles away from the injection sites. It’s possible that more local weakness than average will be produced in CMT patients, especially if the injections are in the legs. However, the risk is likely very small in general, depending on which muscles are injected. There is no evidence that injections will worsen the overall condition.
If Quinine is a neurotoxic substance for people with CMT and Quinine is in tonic water, why is drinking tonic water recommended to people with CMT for nocturnal cramps?
Please consult with your physician before consuming tonic water for nocturnal cramps!
The FDA has banned the use of quinine for nocturnal leg cramps because of its serious side effects. For most people, the low doses of quinine contained in tonic water are not enough to trigger serious side effects. So, most people can use tonic water occasionally and in moderation as a remedy for leg nocturnal cramps.
However, for an unlucky few, even the small amount of quinine in tonic water can cause thrombocytopenia. Thrombocytopenia is a drop in the blood’s platelet count that can lead to internal and external bleeding as well as a related condition that can cause permanent kidney damage.
Are vitamins good or bad for CMT?
There is little research on the effects of vitamins on CMT. Taking too much B6 is bad. Other than that, there is no known risk of taking vitamins as long as you don’t take megadoses of these supplements. A megadose is 10 times or more the RDA.
Are there any indications that Macrodantin might cause shortness of breath?
That is hard to say. There is no neurological reason for that symptom. It is a possible medical side effect that is unrelated to CMT. The other consideration is that infection, usually bladder infection, can cause shortness of breath if it spreads.
Do you recommend taking a lecithin supplement? Why or why not?
In August 2018, it was reported that the dietary supplement lecithin improved the myelination of diseased Schwann cells. The study showed a modest improvement in the rat model of CMT1A but has not yet been duplicated.
Ultimately, if you choose to take a lecithin supplement, you would be wise to consult your doctor in order to establish a safe dosage. The CMTA at this point does not recommend lecithin supplementation, but there are reputable web sites that give approximate doses for treatment of other conditions, like high cholesterol. Care should be taken if there are any allergies to eggs or soy, as these are often sources of lecithin supplements.