Hello robert22,
Can Effexor (venlafaxine) activate a dormant case of Charcot-Marie-Tooth?
?Probably not? is as close as I can get with an answer. I was unable
to find any reliable information stating that CMT
(Charcot-Marie-Tooth, also known as hereditary motor and sensory
neuropathy - HMSN) can be triggered or stimulated by Effexor, or any
other drug. CMT patients should avoid certain drugs that can
exacerbate the condition, but they do not cause it, nor do they awaken
a dormant case of CMT. CMT is a genetic disorder, and as such, you
either have the causative gene, or you don?t. The only time you would
find CMT being ?dormant? would be if the gene has remained dormant in
a family line, until it is expressed in an offspring. There are many
variants of CMT however, some of which can be identified though DNA
testing. Not all genes responsible for the various forms have been
identified. In one of your other questions, I see you mentioned being
tested for CMT, but the genetic marker tests were negative. Blood
tests that test DNA for CMT can detect CMT types 1A and 1X only.
Since you say ?I had EMG and nerve velocites exams that showed an
abnormal result. The nerves conductions velocites seems to be
reduced.? You may have another form of CMT. You may not have CMT at
all, but one of the other neuronal syndromes. I will discuss the
results of nerve conduction velocity testing further in my answer.
Low doses of Effexor may actually help alleviate neuropathy:
?Low-dose Effexor (venlafaxine hydrochloride) successfully palliates
the pain of peripheral neuropathy (PN)?although not the numbness. In
addition to a personal verification of this, there are published
articles describing this use.? And ?It has long been known that
antidepressants help to reduce the pain of neuropathy. Egbunike [1]
reported in 1990 on the use of antidepressants to palliate the pain of
diabetic neuropathy, neuralgia, and phantom limb pain. He pointed out
that the analgesic effects were separate from the antidepressant
effects and that doses used for pain were generally lower than those
used to treat depression. He recommended that doses ?should be started
low and gradually increased until the patient reaches the highest
tolerable dose. Onset of analgesia is variable, ranging from 1 day to
10 weeks.? He did not establish optimum dosages.?
http://www.hormonerefractorypca.org/pneffexor.htm
http://neuro-www.mgh.harvard.edu/forum_2/PeripheralNeuropathyF/8.25.9911.58PMEffexoranti.html
http://www.diabetic-help.com/new_study_shows_effexorr.htm
Part of an interview excerpted here: ?Dr. Carter: Better treatments
for neuropathic pain are already here and available. You are taking
drugs that are "ancient" and only partly effective. Get your doctor to
prescribe drugs like neurontin, topamax, lamictal, Effexor or other
newer anti-depressants (that help like amitriptyline but have much
fewer side effects), lidocaine patches, custom compounded topical
creams. Find a doctor who has joined the 21st century. Get a referral
to a pain specialist (often an anesthesiologist, physiatrist, or
neurologist).?
http://www.lindacrabtree.com/cmtnews/Aging%20with%20CMT/What%20about%20the%20what%20ifs.html
Types of CMT
·CMT Type 1A - a duplicated gene on chromosome 17.
·CMT Type 1B - a genetic defect on chromosome 1.
·CMT Type 1C - the gene responsible for Type 1C hasn't yet been identified.
·CMT Type X-linked - a genetic defect on the X chromosome.
·CMT Type 2A - a genetic defect on chromosome 1.
·CMT Type 2B - a genetic defect on chromosome 3.
·CMT Type 2C - the gene responsible for Type 2C hasn't yet been identified.
·CMT Type 2D - a genetic defect on chromosome 7.
http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Charcot-Marie-Tooth_disorder
CNN Health describes the different variations as such:
·CMT1. The most common type, CMT1 results from defective myelin genes,
those involved in the structure and function of the myelin sheath.
Defective myelin genes can cause a breakdown of myelin
(demyelination), causing the myelin sheath to deteriorate and expose
the peripheral nerves.
·CMT2. This form of CMT is less common and is caused by abnormalities
in the peripheral nerves as opposed to the myelin sheath.
·CMT3. Also known as Dejerine-Sottas disease, CMT3 is a severe form of
CMT that develops during infancy and affects the myelin sheath.
·CMT4. This is the most complicated form of CMT. It involves several
subtypes of demyelinating nerve damage, with each subtype caused by a
different gene defect.
·CMTX. The defective gene that causes CMTX is located on the
X-chromosome. CMTX usually affects males more than females. This is
because females have two X chromosomes that can usually compensate for
a defective copy of the gene on one chromosome with a normal copy on
the other.
http://www.cnn.com/HEALTH/library/DS/00557.html
CMT is not ?just one disease?, but a collection of conditions with
similar neuropathies and symptoms, making it, in medical terms, a
?syndrome? . CMT-1 does produce reduced nerve conduction velocities,
while CMT-2 will produce a near normal nerve conduction velocity but a
with decreased signal amplitudes.
http://users.rcn.com/smith.ma.ultranet/history.html
?Some types of CMT can pass from generation to generation and affect
males and females equally. In other cases of CMT, the disease arises
from a new or spontaneous mutation in a gene rather than from an
inherited defective gene, meaning there's no previous family history
of the disorder.?
http://www.cnn.com/HEALTH/library/DS/00557.html
?The variation in degree of physical disability, together with a lack
of physician awareness of CMT, has often led to misdiagnosis.?
?CMT is generally inherited in an autosomal dominant pattern. This
means that if one parent has the disease (either the father or the
mother) there is a 50% chance of passing it on to each child. CMT can
also be inherited in recessive or an X-linked pattern. To determine
the pattern of inheritance, each CMT patient should consult a genetic
counselor, neurologist or other medical authority familiar with the
disease.?
http://www.charcot-marie-tooth.org/site/content/whatiscmt/index.asp
Some interesting new research: ?Mitochondrial mutations tracked as
cause of Charcot Marie-Tooth disease
Charcot Marie-Tooth disease is a hereditary disorder that causes the
muscles and nerves of the lower legs to atrophy, resulting in
disabilities such as clubfoot and a lack of muscular coordination.
Scientists studying the causes of Charcot Marie-Tooth disease
uncovered information that could lead to a better understanding of
peripheral neuropathies. Genetic mutations in Mitofusin 2, a
mitochondrial assembly protein, are responsible for approximately 20
percent of an inherited axonal Charcot Marie-Tooth (CMT) disease
according to a study involving seven families with histories of CMT.
The research may point to the development of a new pathomechanism for
treating peripheral neuropathies.
American Academy of Neurology
http://www.aan.com/press/press/index.cfm?fuseaction=release.view&release=194
It would be interesting to know when you developed hammer toes and a
high arch, or if you have always had these traits. High arches from
birth mean little, except for discomfort and possible gait and back
problems later in life. Hammer toes can be genetic (as in CMT), but
usually develop from arthritis, tight shoes or a muscular disease. In
the hypertrophic type of CMT, foot deformities usually present before
or around the age of 20. In the neuronal type, foot deformities appear
in the early adult years to middle age.
?In what other ways do the hypertrophic and neuronal types differ?
The small muscles of the hand are more affected in the hypertrophic
type than they are in the neuronal, and sensory changes are more
pronounced. This form of Charcot-Marie-Tooth disease is also
characterised by enlarged (hypertrophic) nerves and by degeneration of
the sheath of fatty material (myelin) that insulates many of the
body's nerve fibres.
The neuronal form of Charcot-Marie-Tooth disease affects lower limb
functions more than the hypertrophic form, and there is comparatively
greater loss of muscle bulk below the knee. Weakness in the ankles and
feet is also likely to be more severe in the neuronal type.?
http://www.mda.org.au/specific/mdacmt.html
Symptoms of CMT:
·High arched foot
·Gait disturbances
·Foot bone abnormalities
·High arches
·Hammer toes
·Problems with hand function
·Balance problems
·Occasional lower leg cramping
·Occasional forearm muscle cramping
·Loss of reflexes
·Muscle degeneration in foot, lower leg, hand, and forearm
·Mild loss of sensation in the limbs, fingers, and toes
·Occasional partial sight loss
·Hearing loss
·Scoliosis (curvature of the spine)
http://www.wrongdiagnosis.com/c/charcot_marie_tooth_disorder/symptoms.htm
?In what other ways do the hypertrophic and neuronal types differ?
The small muscles of the hand are more affected in the hypertrophic
type than they are in the neuronal, and sensory changes are more
pronounced. This form of Charcot-Marie-Tooth disease is also
characterised by enlarged (hypertrophic) nerves and by degeneration of
the sheath of fatty material (myelin) that insulates many of the
body's nerve fibres.
The neuronal form of Charcot-Marie-Tooth disease affects lower limb
functions more than the hypertrophic form, and there is comparatively
greater loss of muscle bulk below the knee. Weakness in the ankles and
feet is also likely to be more severe in the neuronal type.?
http://www.mydr.com.au/default.asp?article=2410
There is no cure for CMT, but people with CMT are expected to live a
normal lifespan.
http://www.ninds.nih.gov/health_and_medical/disorders/charcot_doc.htm#What_is_Charcot-Marie-Tooth_Disorder
+++++++++++++
Effexor and CMT
+++++++++++++
CMT World lists medications that CMT patients should avoid. Effexor is
not on this list as having a toxic effect on the peripheral nervous
system. You should avoid lithium, some chemotherapeutic drugs,
Flagyl, laughing gas, and some TB and HIV medications, among others.
http://www.cmtworld.org/html/cmtrx.php
http://www.drugs.com/MTM/vincristine.html
No toxicity to the peripheral nervous system is noted on this Effexor
monograph site either.
http://www.mentalhealth.com/drug/p30-e02.html#Head_3
Interestingly, some off-label uses of Effexor are the treatment of
cataplexy and narcolepsy. (Off-label uses are when a drug intended for
one condition is found to help a non-related condition --the most well
known off-label use is Minoxidil, a blood pressure medicine, found to
help regrow hair! Another is the use of Viagra to treat pulmonary
hypertension!)
http://www.charityadvantage.com/narcolepsynetwork/spreadtheword.asp
At least one person does seem to feel that Effexor may be causing some
neck stiffness: ?Does anyone have any information about Charcot-
Marie-Tooth patients and anti-depressants? I've had strange neck
stiffness associated with Paxil and Effexor in the past. Now I'm
getting pains in my triceps and elbows. Psychiatrist feels that it is
unrelated. I would be interested in any data or anecdotal
information.? Note that Effexor is NOT an SSRI.
http://neuro-www.mgh.harvard.edu/forum/GeneralNeurologyF/Paxil-variousnotesetc..html
?The difference is thought to result from the fact that Effexor
attacks troubled brain chemistry with a two-pronged approach. Although
SSRIs primarily work through the selective inhibition of serotonin
reuptake, Effexor prevents the reuptake of norepinephrine as well as
serotonin. Says Dr. Thase, "I believe the dual-action mechanism of
action conveyed by venlafaxine increases the chances of patients
obtaining the best treatment outcome--the ability to achieve
remission. This, in turn, may enhance their chances of long-term
recovery."
http://depression.about.com/cs/venlafaxine/a/effexorssris.htm
=====================================
Additional Information and Resources:
=====================================
CMT Genetic Testing
?Because of overlapping clinical symptoms with other inherited
peripheral neuropathies, CMT may be challenging to diagnose
clinically, and CMT2 may be difficult to distinguish from other forms
of CMT, such as CMT1, CMTX, and chronic idiopathic axonal
neuropathy.(6) A genetic test can help clarify a clinical diagnosis
and provide the most accurate information about an individual?s CMT
type, which may help in assigning risks for developing the disease or
passing on the abnormal gene to family members, enable appropriate
genetic counseling, and lead to better disease management.?
http://www.lindacrabtree.com/cmtnews/Testing-Telling/Where%20to%20get%20tested.htm
http://www.mdausa.org/publications/gen_test.html
Interesting articles on CMT.
http://www.pediatric-orthopedics.com/Topics/Muscle_Neuro/Diseases/Neurodegenerative__CMT_SMA_/neurodegenerative__cmt_sma_.html
?CMT NEWS was a Web site put up for those who have Charcot-Marie-Tooth
(CMT) disease, a progressive neuromuscular disorder, by those who have
CMT and their professional healthcare advisors? This site is no longer
updated, and may have some broken links.
http://www.lindacrabtree.com/cmtnews/index.html
Numerous links to CMT resources:
http://www.nlm.nih.gov/medlineplus/charcotmarietoothdisease.html
http://neuro-www.mgh.harvard.edu/forum/PeripheralNeuropathyMenu.html
Good News! ?Scientists at the University of Edinburgh are closer to
correcting an abnormal gene which causes one of the crippling muscle
wasting diseases known collectively as Charcot-Marie-Tooth (CMT)
disease.
Their findings may lead to the development of gene therapy to treat
patients with CMT disease, it is reported in the current issue of
Nature.
?
http://www.news-medical.net/?id=4652
Some interesting takes on Effexor:
http://www.crazymeds.org/effexor.html
http://www.hc-sc.gc.ca/hpfb-dgpsa/tpd-dpt/effexor_hpc_e.html
http://qualitycounts.com/drugs/effexor_venlafaxine.html
Finally, has your doctor suggested Neurontin for treating your
neuropathy? Have you been tested for diabetes?
http://www.pfizer.com/download/uspi_neurontin.pdf
There you go robert22. I hope this clears things up for you. Please
keep in mind that this answer is not intended to replace sound medical
advice from a licensed physician, and is for informational purposes
only.
If any part of my answer is not clear, or if I have duplicated
information you already had, please request an Answer Clarification.
By using the Answer Clarification process, before rating this answer,
I will be able to assist you further, if possible.
I wish you the best.
Sincerely,
crabcakes
Search Terms
============
charcot marie tooth triggers
Dormant CMT
effexor + neuropathy
CMT + Effexor
Effexor + Charcot Marie Tooth
off label uses effexor
effexor + peripheral neuropathy |
Clarification of Answer by
crabcakes-ga
on
20 Sep 2004 23:52 PDT
Hi again robert22,
I found this 2000 document, from the FDA regarding additional side
effects of Effexor. No mention is made of neuropathy in this
particular document.
?Abrupt discontinuation or dose reduction of venlafaxine at various
doses has been found to be associated with the appearance of new
symptoms, the frequency of which increased with increased dose level
and with longer duration of treatment. Reported symptoms include
agitation, anorexia, anxiety, confusion, coordination impaired,
diarrhea, dizziness, dry mouth, dysphoric mood, fasciculation,
fatigue, headaches, hypomania, insomnia, nausea, nervousness,
nightmares, sensory disturbances (including shock-like electrical
sensations), somnolence, sweating, tremor, vertigo, and vomiting. It
is therefore recommended that the dosage of Effexor be tapered
gradually and the patient monitored. The period required for tapering
may depend on the dose, duration of therapy and the individual
patient. Discontinuation effects are well known to occur with
antidepressants."?
http://www.fda.gov/medwatch/safety/2000/mar00.htm#effexo
This newer document, does indeed mention neuropathy as an infrequent
side effect of Effexor. If you look at Page 16, where side effects
begin, you will se no mention of nerupathy. On Page 21, however,
neurpathy is listed as an infrequent side effect. Infrequent here
means in a clinical trial study, that 1 in 100 to 1 in 1,000 people
experienced this side effect. Note also this sentence: ?It is
important to emphasize that, although the events reported occurred
during treatment with venlafaxine, they were not necessarily caused by
it.?
http://www.fda.gov/cder/foi/label/2001/20699s15lbl.pdf
Other sites do not mention neuropathy however:
?What about side effects?
Relatively few side effects have been reported with Effexor XR. Those
that have been noted are dose-related; that is, side effects increase
as the dose increases. Very few patients have had to discontinue the
medication because of side effects.
The most common minor side effects during clinical trials include
short-term nausea (which can be reduced by taking the medication with
food), sleepiness, dry mouth, dizziness, constipation, nervousness,
sweating, weakness, ejaculation/orgasm problems, and loss of appetite.
A small percentage (about five percent) of patients, usually those
taking higher doses, will develop elevated blood pressure. Therefore,
patients taking Effexor XR should have their blood pressure checked
regularly. Some agitation has been noticed at higher dosages. Patients
who stop Effexor XR abruptly may experience dizziness, nausea,
vertigo, and shock-like symptoms. Therefore, slow tapering is
recommended.?
http://www.nami.org/Template.cfm?Section=About_Medications&template=/ContentManagement/ContentDisplay.cfm&ContentID=7393
http://www.rxlist.com/cgi/generic/venlafax_ad.htm
If you experience any of the following serious side effects, stop
taking venlafaxine and contact your doctor immediately or seek
emergency medical treatment:
·an allergic reaction (difficulty breathing; closing of the throat;
swelling of the lips, tongue, or face; or hives);
·seizures; or
·an irregular heartbeat or severely high blood pressure (blurred vision, headache).
?Other, less serious side effects may be more likely to occur.
Continue to take venlafaxine and talk to your doctor if you experience
·nausea, vomiting, upset stomach, abdominal pain, or loss of appetite or weight;
·dry mouth;
·drowsiness or dizziness;
·mild tremor, anxiety, or agitation;
·insomnia;
·abnormal dreams;
·sexual problems such as impotence, abnormal ejaculation, difficulty
reaching orgasm, or decreased libido;
·sweating
·yawning; or
·increase in blood cholesterol levels (detected by blood tests);
? Side effects other than those listed here may also occur. Talk to
your doctor about any side effect that seems unusual or that is
especially bothersome.
http://effexor.drugs.com/
?Nervous system side effects including insomnia, somnolence, tremor,
dizziness, headache, anxiety, nervousness, delirium, and fatigue have
all been reported. The reported incidence of each of these effects
ranges between 10% and 20% of treated patients. Venlafaxine has been
reported to increase the pain tolerance threshold to electrical sural
nerve stimulation and the threshold at which pain increases (pain
summation). One small study has suggested that venlafaxine may improve
attention, concentration, memory, and reaction time performance after
single oral doses. Dyskinesia has also been reported. One case of
serotonin syndrome has been reported which is believed to have been
precipitated by the combination of venlafaxine and trazodone.?
http://www.subscriberx.com/iqhealth/SideEffect.asp?drugname%3DEffexor%3Bdrugid%3D594%20
http://remedyfind.com/rm-2819-Effexor.asp
It?s possible then that the Effexor may have caused your neuropathy,
but it is not very probable. As you will read in the next paragraph,
some CMT patients seem to develop neuropathy as part of the CMT
syndrome.
==========
Neurontin:
==========
I?ve compiled some sites with information about Neurontin for you.
Remember, your doctor is the only one who can decide if this is a drug
for you, as s/he has access to your health history. It may not be
compatible with other prescriptions you may be taking, or it may be
contraindicated for your use for a number of reasons.
?I was first diagnosed with Charcot-Marie-Tooth (CMT) disease at age
11; I'm now 47. Over the years I tried a variety of medications, all
of which made me worse. Recently, I was advised to take Neurontin
(brand name for gabapentin), 900 mg/day, for my pain ? a whole new
pain-free life was opened up for me. Without much success, I've tried
to find information about how Neurontin works to stop the pain, give
me stamina, energy, balance, good mood and even increased libido. Have
there been any studies on the benefits of Neurontin for people with
CMT??
Reply #1 from Michael E. Shy, M.D., Wayne State University School of
Medicine, Detroit, MI:
Neurontin (generic name gabapentin) 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, gabapentin 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 about how some of these
medications work, how gabapentin stops pain is not clear. Of interest
is the fact that other anti-seizure medications like phenytoin
(Dilantin),or carbamezepine (Tegretol) also treat pain in some
patients with neuropathy.
Reply #2 from David Pleasure, M.D., Children's Hospital of Philadelphia, PA:
There have been a considerable number of studies of the use of
gabapentin in neuropathic pain. In some instances, good results have
been obtained. No specific publications on gabapentin in CMT have
appeared.
http://www.mdausa.org/experts/question.cfm?id=1681
?Neurontin® has been approved for use in the treatment of
post-herpetic neuralgia and there is scientific research that
indicates it may be effective in the treatment of other conditions
that result in neuropathic pain.?
http://www.guideline.gov/summary/summary.aspx?doc_id=3550
http://www.pslgroup.com/dg/D6AC6.htm
http://neuroland.com/pain/neurontin.htm
?Question: I am 65 years of age and am taking 2400 mg of Neurontin a
day for peripheral neuropathy in my feet. I take the drug three times
a day 2 - 3 - 3. If I have unusual discomfort before my next dose I
take Ultran. What is the maximum amount of Neurontin that I can take?
(of course I would consult my physician) I have no side effects that I
notice or anyone else notices. I work full time and other than
medication for high blood pressure and estrogen, I do not take any
other medications. I do of course take calcium, vitamin E and a multi
vitamin. Your comments would be appreciated.
Answer: Well, hard to say. Some physicians have increased it to very
large doses for peripheral neuropathy without problems, but most would
keep it under 5-600 mg a day.?
http://www.druginfonet.com/index.php?pageID=faq/faqnurtn.htm
Your best source of information will be found here:
http://www.pfizer.com/download/uspi_neurontin.pdf
This site is HIV related, but has some good information about
Neurontin, and other tips for neuropathy.
http://www.aegis.com/factshts/network/simple/neurop.html
Studies links:
http://home.tampabay.rr.com/lymecfs/neurontin01.htm
I hope this clarification has been helpful to you, robert22.
Sincerely,
crabcakes
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