How Effective Is Carbamazepine For Neuropathy Pain

Today's post from onlinelibrary.wiley.com (see link below) is an objective assessment of the effects of carbamazepine on neuropathic pain and as such is always useful for neuropathy patients looking for confirmation that what they're being prescribed is what the doctor says it is. Carbamazepine has become increasingly popular recently, as an alternative to other anti-epilepsy drugs such as Lyrica, which has a possibly deserved bad press. However, does the research show that it works? This article suggests that it does...for some people but with caveats. Pretty much the same as all other drugs used to treat neuropathic pain then! Worth a read if you're on Carbamazepine, or likely to encounter it in the course of your treatment options.

Carbamazepine for chronic neuropathic pain and fibromyalgia in adults 
Philip J Wiffen1,*, Sheena Derry1, R Andrew Moore1,Eija A Kalso2,3
Editorial Group: Cochrane Pain, Palliative and Supportive Care Group
Published Online: 10 APR 2014
Assessed as up-to-date: 7 FEB 2014

DOI: 10.1002/14651858.CD005451.pub3

Copyright © 2014 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
The Cochrane Library
Read a clinical summary of this review on

Abstract

Background

This is an update of a Cochrane review entitled 'Carbamazepine for acute and chronic pain in adults' published in Issue 1, 2011. Some antiepileptic medicines have a place in the treatment of neuropathic pain (pain due to nerve damage). This updated review considers the treatment of chronic neuropathic pain and fibromyalgia only, and adds no new studies. The update uses higher standards of evidence than the earlier review, which results in the exclusion of five studies that were previously included.

Objectives

To assess the analgesic efficacy of carbamazepine in the treatment of chronic neuropathic pain and fibromyalgia, and to evaluate adverse events reported in the studies.

Search methods

We searched for relevant studies in MEDLINE, EMBASE and CENTRAL up to February 2014. Additional studies were sought from clinical trials databases, and the reference list of retrieved articles and reviews.

Selection criteria

Randomised, double blind, active or placebo controlled trials (RCTs) investigating the use of carbamazepine (any dose, by any route, and for at least two weeks' duration) for the treatment of chronic neuropathic pain or fibromyalgia, with at least 10 participants per treatment group. Participants were adults aged 18 and over.

Data collection and analysis

Two study authors independently extracted data on efficacy, adverse events, and withdrawals, and examined issues of study quality. Numbers needed to treat for an additional beneficial effect (NNT) or harmful effect (NNH) with 95% confidence intervals (CIs) were calculated from dichotomous data.

We performed analysis using three tiers of evidence. First tier evidence derived from data meeting current best standards and subject to minimal risk of bias (outcome equivalent to substantial pain intensity reduction, intention-to-treat analysis without imputation for dropouts, at least 200 participants in the comparison, at least 8 weeks' duration, parallel design), second tier from data that failed to meet one or more of these criteria and were considered at some risk of bias but with adequate numbers in the comparison, and third tier from data involving small numbers of participants that was considered very likely to be biased or used outcomes of limited clinical utility, or both.

Main results

Ten included studies (11 publications) enrolled 480 participants with trigeminal neuralgia, diabetic neuropathy, and post stroke pain. Nine studies used a cross-over design, and one a parallel group design. Most of the studies were of short duration, lasting four weeks or less.

No study provided first or second tier evidence for an efficacy outcome. Using third tier evidence, carbamazepine generally provided better pain relief than placebo in the three conditions studied, with some indication of pain improvement over mainly the short term, but with poorly defined outcomes, incomplete reporting, and in small numbers of participants. There were too few data in studies comparing carbamazepine with active comparators to draw any conclusions.

In four studies 65% (113/173) of participants experienced at least one adverse event with carbamazepine, and 27% (47/173) with placebo; for every five participants treated, two experienced an adverse event who would not have done so with placebo. In eight studies 3% (8/268) of participants withdrew due to adverse events with carbamazepine, and none (0/255) with placebo. Serious adverse events were not reported consistently; rashes were associated with carbamazepine. Four deaths occurred in patients on carbamazepine, with no obvious drug association.

Authors' conclusions

Carbamazepine is probably effective in some people with chronic neuropathic pain, but with caveats. No trial was longer than four weeks, had good reporting quality, nor used outcomes equivalent to substantial clinical benefit. In these circumstances, caution is needed in interpretation, and meaningful comparison with other interventions is not possible.

Plain language summary

Carbamazepine for chronic neuropathic pain and fibromyalgia in adults

Neuropathic pain is pain coming from damaged nerves. It is different from pain messages carried along healthy nerves from damaged tissue (a fall, or cut, or arthritic knee). Neuropathic pain is treated by different medicines than pain from damaged tissue. Medicines like paracetamol or ibuprofen are not effective in neuropathic pain, while medicines that are sometimes used to treat depression or epilepsy can be very effective in some people. Our understanding of fibromyalgia (a condition of persistent, widespread pain and tenderness, sleep problems, and fatigue) is lacking, but fibromyalgia can respond to the same medicines as neuropathic pain.

Carbamazepine was developed to treat epilepsy, but it is now used to treat various forms of chronic pain. We performed searches (up to February 2014) to look for clinical trials where carbamazepine was used to treat neuropathic pain or fibromyalgia. We found 10 studies involving 418 people involved in testing carbamazepine. Studies were not generally of very good quality. Most were very small, as well as of short duration. Studies lasting only one or two weeks are unhelpful when pain can last for years.

There was not enough good quality evidence to say how well carbamazepine worked in any neuropathic pain condition. Pooling four small studies showed that it was better than placebo, but the result cannot be relied upon. There was not enough information from these studies to make any reliable comment on adverse events or harm.

Carbamazepine is probably helpful for some people with chronic neuropathic pain. It is not possible to know beforehand who will benefit and who will not. 


http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD005451.pub3/abstract

Is Marijuana Effective Against Neuropathic Pain

Today's post is from scientistlive.com (see link below) and is yet another article about the benefits of marijuana for neuropathy patients. It's based on another small study by researchers at San Diego School of Medicine but the 'cannabis as analgesic' evidence is mounting with time. Others are also working on cannabis derivatives which don't give the high and don't require you to smoke, which could be beneficial to ex-smokers and people who aren't keen on getting stoned. An extract of cannabis has been developed into a drug for multiple sclerosis called Sativex. This is taken as a spray under the tongue. An artificial form of cannabis’ active ingredient delta 9-tetrahydrocannabinol (THC) is also licensed, as dronabinol (Marinol). These preparations do not cause the ‘high’ of the illegal drug.
*The biggest problem for neuropathy patients who wish to go down this road, is the legal one. It's then a lottery as to where you live and what the laws are but wherever that may be, let's hope that it doesn't lead to what happens in tomorrow's video post, which may put you off forever!

Marijuana effective against HIV pain 
  

In a double-blind, placebo-controlled clinical trial to assess the impact of smoked medical cannabis, or marijuana, on the neuropathic pain associated with HIV, researchers at the University of California, San Diego School of Medicine found that reported pain relief was greater with cannabis than with a placebo. The study, sponsored by the University of California Center for Medical Cannabis Research (CMCR) based at UC San Diego, will be published on line, August 6 in the journal Neuropsychopharmacology.

Led by Ronald J. Ellis, M.D., Ph.D., associate professor of neurosciences at UCSD School of Medicine, the study looked at 28 HIV patients with neuropathic pain not adequately controlled by other pain-relievers, including opiates. They took part in the controlled study as outpatients at the UCSD Medical Center. The proportion of subjects achieving pain reduction of 30 percent or more was greater for those smoking cannabis than those smoking the placebo.

"Neuropathy is a chronic and significant problem in HIV patients as there are few existing treatments that offer adequate pain management to sufferers," Ellis said. "We found that smoked cannabis was generally well-tolerated and effective when added to the patient's existing pain medication, resulting in increased pain relief."

Each trial participant participated in five study phases over seven weeks. During two five-day phases, randomly selected participants smoked either cannabis or placebo cigarettes made from whole plant material with cannabinoids (the psychoactive compound found in marijuana) removed, both provided by the National Institute on Drug Abuse. Outcome was tested by standardised tests measuring analgesia (lessened pain sensation), improvement in function and relief of pain-associated emotional distress.

Using verbal descriptors of pain magnitude, cannabis was associated with an average reduction of pain intensity from 'strong' 'to mild-to-moderate' in cannabis smokers, according to Ellis. Also, cannabis was associated with a sizeable (46% versus 18% for placebo) proportion of patients reporting clinically meaningful pain relief.

The study's findings are consistent with and extend other recent research supporting the short-term efficacy of cannabis for neuropathic pain, also sponsored by the CMCR.

"This study adds to a growing body of evidence that indicates that cannabis is effective, in the short-term at least, in the management of neuropathic pain," commented Igor Grant, M.D., professor of psychiatry and director of the CMCR.

http://www.scientistlive.com/European-Science-News/Pharmacology/Marijuana_effective_against_HIV_pain/20850/