Re: drug induced neuropathy

Posted By Lyn on November 22, 1998 at 18:01:10:

In Reply to: Re: drug induced neuropathy posted by CCF Neurology MD:NT on November 20, 1998 at 17:06:38:






: : Dear Dr.
: : Can  you tell me if a drug induced sensory neuropathy can resolve in time if it is to your small fiber nerves or nerves just below the skin that have been affected?  I called the drug manufactuer as post marketing adverse reaction listed paresthesia on the insert.  But, they said they have no information they could give me. because it was post marketing information. All my doctors feel this caused my problem. What do you think the chances are that something like this will resolve in time?  I assume you must have had some other cases. I appreciate what your opinion is.




Dear Lyn:
A small fiber sensory neuropathy can occur from a variety of causes, and some drugs are certainly on the list. Finding "parathesia" listed on the list of side effects in the insert or in the PDR does not mean that the drug is a potential cause of a neuropathy. In fact, paresthesias are very nonspecfic symptoms and are on the list of side effects of numerous very innocuous drugs.
Reading your description I am not quite sure that you suffer from a neuropathy. Besides a clinical examination, additional tests such as EMG, quantitative sensory and autonomic tests, and blood tests, and even a nerve or skin biopsy may be needed to make a definite diagnosis.
The troubles caused by sensory neuropathy are of three types. The commonest is severe pain. The less common symptoms are clumsiness and incoordination, and damage to distal extremities and skin from the loss of protective benefits of normal pain and sensation. Some of these troubles may or may not recover depending upon cause and severity. Paim may be controlled with drugs.
Good luck!
Thanks for your answer but maybe you can clarify something more as your answer confused me.  I have had TWO EMG studies and quantitative sensory tests up the ying yang that have determined that I indeed have SENSORY NEUROPATHY.  I have had every test a MAYO Clinic or Johns Hopkins or You would do to rule out other causes.  My doctors feel that the drug created this problem based on my particular case.  You state that some of these troubles may or may not recover depending upon the cause and severity.  Though my problem has been deemed a mild sensory neuropathy the pain has been unbearable but has improved a tiny bit in 6 months, but it is still very much there. I have opted off all pain medications for now as I had such nasty side effects, that I couldn't stand what they did to me.    Since this has been deemed MILD sensory Neuropathy (and polysensory meaning in several places) and is deemed MILD in severity and the CAUSE being a drug.  In these type of cases MILD AND DRUG INDUCED NEUROPATHIES knowing that you are not Houdini!  What is Cleveland Clinics general statistical conclusion.  If you had a patient who presented with a Sensory neuropathy that was definitely linked to being drug induced and deemed mild-- what would you say knowing the cause was a drug and severity mild  would be the odds of such type cases improving or resolving in time????????
You say Paresthesias are sort of a catch phrase.  Maybe they are I personally would love to see a warning on some particular drug inserts that say WARNING: Can Cause Permanent Nerve Damage and Neuropathy for life.  or Known to cause Sensory Nerve Damage in Healthy People. It wouldn't be good for marketing, but it would save alot of people the agony of what I've been living through.   It would be interesting if Cleveland Clinic did some research on this.  I'm sure alot of things labeled Idiopathic might actually have a true cause if some further research was done.  Sorry about the speech.  I just would like your opinion on the odds of a Mild Sensory neuropathy resolving in time if it was caused by a drug.
Please give me your best guess????????????Thanks again!






: Dear Lyn:
Demonstrating with reasonable certainty that a drug or environmental substance is a CAUSE of specific side effects is not easy. In the least, it requires a case-control study of large numbers.  It is possible that rare mild side-effects of drugs are not identified by the rigor of the statistical methods. However, it is also improper to blame a drug for a side effect it does not cause, just because it coincidentally happened to be taken about the time an otherwise unexplained medical disorder occured. All drug companies do extensive post-marketing surveys for major side effects (including neuropathies, liver dysfunction, myopathy, bone marrow dysfunction, etc). It is possible that your case is a previously unreported side effect of a drug; if your neurologist is convinced that this is a possibility, it would be his responsibility to report this to the drug manufacturer.
Again, parasthesias are NOT synonymous with nerve damage. If a drug manufacturer is aware of neuropathy as an adverse effect, it is required by law to state precisely this in the package insert
The cause of neuropathy can be very difficult to diagnose. Despite the best of methods, as many as 40 percent of cases with neuropathy do not have an identifiable cause.
For such idiopathic neuropathies, the prognosis is best determined by the track-record of the neuropathy. If the neuropathy has been very long-s
Dear CCF,
Thanks for the response.  While I may agree with you that it is improper to blame a drug without appropriate research.  Likewise I feel a drug that does cause Neuropathy CLEARLY must list this on their Drug Insert.  I find it too much a coincidence that I have come across several cases on the internet of the same scenario unfolding after exposure to this particular drug.
The Manufacturer informed me they DO NOT have or do any research on POST MARKETING adverse effects. That the only research they had was done on clinical trials but NONE on Post Marketing adverse events!  I personally don't consider this a MILD side effect when your life has been impacted to such a degree for over a 6 month period that one is rendered unable to function or work and  suffers agonizing pain.  All other postings I have found of a similar nature all have long term effects that have yet to resolve in a period of months. Clearly there is a difference between idopathic and just not making the correlation because no research has been done!  Thanks for your best guess about such a thing resolving!