NeuroTalk Support Groups - View Single Post - DRUGS (RX) ~~ Used for Treating Peripheral Neuropathy:

mrsD · 12-01-2011, 02:01 PM

I am going to do a whole post on just these two. The other anti-seizure drugs will follow in their own post.

Neurontin (gabapentin) and Lyrica (pregabalin) are cousins.
They are both made by Pfizer, and have both been involved with fines and fraud claims against Pfizer who plead guilty and paid them.

Here are some links for that history: Neurontin
http://articles.sfgate.com/2004-05-1...tin-pfizer-fda
This is a long article.

http://en.wikipedia.org/wiki/Gabapentin

The Neurontin issue was inherited from ParkeDavis, who initially sent sales reps to doctors to encourage experimentation on patients off label for bipolar and chronic pain. They got caught eventually not long after Pfizer took over ParkeDavis.

I found an interesting PubMed review article from 2011, with some facts about the "effectiveness" of Neurontin in treating pain:
http://www.ncbi.nlm.nih.gov/pubmed/21412914
For those reading here not getting much relief--- this is why.
Only found useful in about 1/3 of patients.

This is the side effect profile for Neurontin from FDA reports:
http://www.drugcite.com/?q=Neurontin

This is Neurontin's monograph at Rxlist.com
http://www.rxlist.com/neurontin-drug.htm

Many people cannot tolerate this drug, and its nicknames over the years include Morontin, and Neurotten.

The Wiki article on Neurontin offers this mechanism of action, which still remains murky:

Quote:

Gabapentin was initially synthesized to mimic the chemical structure of the neurotransmitter gamma-aminobutyric acid (GABA), but is not believed to act on the same brain receptors.

One possible mechanism of action, reported by Ben Barres of Stanford University and colleagues in Cell in 2009, was that gabapentin halts the formation of new synapses.[41] Gabapentin binds to the α2δ subunit (1 and 2) and has been found to reduce calcium currents after chronic but not acute application via an effect on trafficking[42] of voltage-dependent calcium channels in the central nervous system.[43] This effect on calcium channel trafficking is another possible mechanism of action of gabapentin, but the exact mechanism remains in dispute.

http://en.wikipedia.org/wiki/Gabapentin

Edit to add.... this link explains how gabapentin works in the brain:
http://www.wellnessresources.com/stu...rain_synapses/

Quote:

In their new study, Barres and his colleagues found that when gabapentin was administered in developing mice, it bound to alpha2delta-1, preventing thrombospondin from binding to the receptor and, in turn, impeding synapse formation. Likewise, by blocking thrombosponin, gabapentin may reduce excess synapse formation in vulnerable areas of the human brain.

While this may be crucial for children... adults still may be affected in ways we haven't explained yet. It is something to think about, certainly.

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Lyrica is a more potent form of Neurontin: It is not generic yet, and remains very expensive.
And it, also, has been in scandals involving Pfizer:
http://www.bloomberg.com/apps/news?p...d=a4h7V5lc_xXM
fraud for Lyrica

Here is the Wiki on Lyrica:
http://en.wikipedia.org/wiki/Pregabalin

And the FDA reports:
http://www.drugcite.com/?q=Lyrica

Both of these drugs are highly sedating, and interact with other sedating drugs. So be careful with them if you use opiates or benzos.

They are mostly excreted whole through the urine by the kidneys, and for that reason do not enhance or block liver metabolism of other drugs. This makes them very attractive to doctors, who think this trait is safer than other anti-seizure drugs. Hence these are offered today FIRST in most PN treatments.

Many people find they cause weight gain. Also some people are appearing on these boards with rotten teeth. (I cannot find that yet in reports however). Both these drugs may cause edema, severe fatigue/brain fog etc. And both have FDA warning regarding suicidal ideation and depression.
This is the RX information for Lyrica:
http://www.rxlist.com/lyrica-drug.htm

So if you are taking one of these and feel they are not working, they probably aren't. Discuss this with your doctor. These drugs cannot be stopped cold turkey after being used for a long time...
that may result in seizures. So any change in therapy should be monitored by your doctor closely.

edit to add this information on two new recent studies showing
Lyrica not effective for pain (no better than placebo)
http://health.yahoo.net/news/s/nm/pf...o-pain-studies

http://www.foxbusiness.com/industrie...-lyrica-trial/

edit to add an example of a taper schedule:
This is a taper from Neurontin with Lyrica added that Nide44 has posted in the past. I have his permission to copy it here:

Quote:

Day 1 - 3
50 mg Lyrica, 900 mg Neurontin three times per day

Day 4-6
100 mg Lyrica , 300 mg Neurontin three times per day

Day 7 and on
150 mg of Lyrica three times per day

This is a taper specific to Nide44's medical condition. Tapers may vary,
according to patients needs and symptoms resulting from the change in dosing.
I recently found this paper, which suggests a slower taper for gabapentin because some people are very uncomfortable with this situation.:

Quote:

Bipolar Disord. 2005 Jun;7(3):302-4.
Gabapentin withdrawal syndrome in the presence of a taper.
Tran KT, Hranicky D, Lark T, Jacob Nj.
Source

Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA. kientran1975@yahoo.com
Abstract
OBJECTIVE:

To report a case report of a geriatric patient with a 5-year history of gabapentin use for enhanced bipolar control, who was tapered off of gabapentin over 1 week. The patient displayed unique withdrawal symptoms after the taper of gabapentin.
METHODS:

The patient is an 81-year-old white female with a life-long history of schizoaffective disorder with bipolar type I tendencies who had been prescribed gabapentin for 5 years.
RESULTS:

The patient displayed moderate upper respiratory tract infection symptoms and somatic complaints 1 day after termination of gabapentin. These symptoms gradually worsened until 10 days after, at which time she acutely developed severe mental status changes, severe somatic chest pain, and hypertension. Physical examination, electrolytes, electrocardiogram, computerized tomography, magnetic resonance imaging, and magnetic resonance angiography were all normal. Upon reintroduction of gabapentin, the patient returned to baseline within 1-2 days.
CONCLUSIONS:

Gabapentin is widely utilized currently for the chronic treatment of recalcitrant migraines, bipolar illness, pain, and epilepsy. It has a wide therapeutic index with few side effects and drug interactions, is not hepatically metabolized, and is excreted by the kidneys. Past reports have suggested that some withdrawal symptoms can present after 1-2 days upon abrupt discontinuation of gabapentin after chronic use within young to middle-aged patients. These symptoms mimic that of alcohol and benzodiazepine withdrawal purportedly due to a similar mechanism of action. Unique to this case is that this geriatric patient developed debilitating withdrawal symptoms after a gradual, week-long taper of gabapentin along with flu-like symptoms. It is proposed herein that a gabapentin taper should follow a course similar to that of a benzodiazepine taper -- slowly and over a period of weeks to months.

PMID:
15898970
[PubMed - indexed for MEDLINE]

from http://www.ncbi.nlm.nih.gov/pubmed/15898970

So based on patient response to a taper, I suggest you keep your doctor informed of any discomfort or alarming symptoms, so that your taper fits your specific needs.