Tuesday, 7 June 2016

Other Drugs May Cause Neuropathy (Or Make It Worse)

Today's post from neuropathyjournal.org (see link below) is another very interesting article coming via the website of LtCol Eugene B Richardson and talking about how neuropathy can both be caused by and made worse due to the use of other medications. Unfortunately, many people living with neuropathy are also living with other conditions. These conditions may be the cause of their nerve damage or they may not but the point is, that other prescribed drugs come into play and can very often either bring on neuropathy or make it much worse. It's an often underestimated cause and effect element of living with nerve damage. Hopefully your doctor is well aware of contra-indications and side effects but don't count on it; especially if you visit a series of specialists, who tend to live in their own little worlds of specialism and have little time for the other illnesses in your dossier. Therefore we need to be yet again responsible for our own health and do our own research on the drugs we need to take. This article should nudge you into action regarding your own medication diet and if you feel that one drug is making your condition worse, have a serious discussion with your doctor.

Medication Induced Neuropathy
By LtCol Eugene B Richardson, USA (Retired) BA, MDiv, EdM,

Peter D. Donofrio, M.D. is professor of Neurology and director of the Neuromuscular Division of the Department of Neurology at Vanderbilt University Medical Center. He is director of Neuropathy Center at Vanderbilt.

Read the excellent article by Dr. Donofrio on Medication Induced Neuropathy that is printed below. The limits of the blood-brain and blood nerve barriers are known through research in many disease processes and the influence of genetics or metabolic factors in the vulnerability of some patients to certain disease conditions. The concept of the blood brain and blood nerve barriers have been misused by expert neurologists to acknowledge medication induced neuropathy while denying that toxic herbicides cause neuropathy whether it be Agent Orange (Vietnam War) or other toxins manufactured by chemical companies. Why?

However, in recent articles in the Journal of the Peripheral Nervous System, it is noted that the blood brain and blood nerve barriers do not work perfectly and often does not prevent damage to the peripheral nerves or even the brain as originally thought. The fact noted by Dr. Norman Latov in his book for patients, genetic factors play an important role in a patients susceptibility to certain neuropathies.

Here is Dr. Donofrio, article:

Medication-Induced Neuropathy
By Peter D. Donofrio, M.D.

You’ve undoubtedly heard the old saying, “It’s what you don’t know that can hurt you.” When it comes to neuropathy, there may be something your doctors don’t know that can hurt you as well.

Renowned New York Times health columnist Jane Brody recently shared with readers of her column that she experienced a bout of peripheral neuropathy several decades ago when a misplaced shot of morphine damaged a sensory nerve in her thigh. Obviously, her doctor never intended for that to happen. Fortunately, the nerve recovered in three years, but for much of that time, Brody couldn’t even tolerate something brushing against her leg.¹ Brody’s peripheral neuropathy can be categorized as an “iatrogenic” case—that is, a condition that is actually caused by medical care.

Iatrogenic causes for peripheral neuropathy aren’t always as blatant as a misplaced shot. In fact, peripheral neuropathy can be caused by nerve toxicity from commonly prescribed drugs: medications prescribed by physicians who are not aware of the possible relationship between the medication and the neuropathy. Why aren’t they aware? After all, aren’t these the experts you trust with your health, your well-being…your life?

Your doctors are well aware of the medications they are prescribing, but the fact is they may not be aware of medications other physicians have prescribed, nor are they aware of every uncommon adverse reaction of a medication. Many medications have hundreds of reported side effects. Often primary care physicians are inundated by a waiting room full of very ill patients requiring immediate care and don’t have time to fully review in detail every note or test result they receive.

Simply put, your specialists and primary physicians need your help. If you have a neuropathy and are concerned it may arise from a medication, speak up. Some medications and interactions between drugs can cause complications and even irreversible conditions. For example, thalidomide has proven to be very effective for treating skin diseases and some kinds of cancer. In fact, thalidomide has experienced a resurgence of use in the medical community for its effectiveness against several dermatological conditions. The occurrence of neuropathy, however, has also been tied to thalidomide. It is not typically related to the daily dose of the drug nor the duration of treatment; it’s more commonly found in patients who are slow drug acetylators—in other words, those patients whose bodies take longer to metabolize certain drugs.

The good news is that when patients with neuropathy stop using thalidomide, 25 percent of them recover completely, and 30 percent improve partially. What’s not so comforting is the fact that 45 percent of reported cases do not recover at all.² This example illustrates the need for you to consult with your physician if you take any of the medications associated with causing neuropathy. It is important to remember that you are not expected to be a medical expert, however, you are expected to know the names of the medications you’re taking, how long you have been taking them, and to be able to describe them to every doctor you visit. Thus, you need to assume the role of being your own patient advocate. Today’s health care system is complicated, and as such, you need to be able to provide to your doctor and to other health care providers as much information about your treatments as possible. Communication of your medications and duration of use is critical for your primary care and specialist physicians to offer you excellence in care.

Take the first step by reviewing the list of medications below that can induce neuropathy and let your physicians know if you are taking any of them. Remember to tell your physicians that you are not questioning their judgment; just asking them to review the medications in the context of your neuropathy. More often than not, they will welcome this active role in your treatment and see this as an opportunity to better educate themselves. Not only will you be helping yourself, but you could be helping others as well. Also, keep in mind that these medication do not always cause neuropathy, and it is the unique metabolism of certain patients that may cause them to develop neuropathy when prescribed a certain drug.

The following is a list of drugs that can cause neuropathy in certain patients:

Danosine (ddl)
Etoposide (VP-16)
contaminant Mercury
Nitrous Oxide
Stavudine (d4T)
TNF-alpha antagonists
Tumor Necrosis Factor
Zalcitabine (ddC)

The peripheral nerves are protected by a blood-nerve barrier and might be perceived to be at a lessened risk than other organs for toxicity. Certain patients, however, may be at a higher risk for developing peripheral nerve toxicity due to genetic or metabolic factors. Many therapies have toxicities that must be tolerated because the treatments are necessary, such as treatments for HIV and malignancy. Developing additional therapies to prevent and/or ameliorate the toxic neuropathy associated with certain medications is an important area of research and clinical trials are on-going.

2015 UPDATE:
Reports from the FDA information on Fluoroquinolone has noted significant instances of chronic peripheral neuropathy. Military doctors wrote 1.2 million scripts for this drug during the Gulf War and many believe that it is the cause of the Gulf War Syndrome or Fluoroquinolone Toxicity Syndrome.

1 Brody, Jane. “The Many Ills of Peripheral Nerve Damage.” The New York Times, October 20, 2009.

2 Zimmer, Carl. “Answers Begin to Emerge on How Thalidomide Caused Defects.” The New York Times, March 16, 2010.

In 2006, Dr. Donofrio accepted the position of Chief of the Neuromuscular Section in the Department of Neurology at Vanderbilt University. In addition, he is the Head of the Muscular Dystrophy Association Clinic, the ALS Clinic, and is the Director of the EMG Lab. He is presently on the Board of Directors of the American Academy of Neuromuscular and Electrodiagnostic Medicine (AANEM) and serves on the Medical Economics and Management Committee of the American Academy of Neurology.

See: Textbook of Peripheral Neuropathy, Peter D Donofrio, MD, Editor, Professor of Neuropathy, Chief of Neuromuscular Section, Vanderbilt University Medical Center, Nashville, TN Published by DEMOS Medical, 2012.


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