Cannabis/Cannabinoids/Neuropathic pain (Part 1)

Where ever you look on the internet, the general conclusion regarding effective treatments for neuropathic pain seems to suggest that only three things really work: capsaicin, smoked cannabis and rhNGF (nerve growth factor). The latter has not been approved by the major national organisations and we have discussed capsaicin at length in other posts on the blog.
This is the first of two more posts with reasonable explanations supporting Cannabinoids. Legal problems aside, there seems to be a growing cache of evidence supporting the efficacy of cannabis, not only as an analgesic but as something with positive effects on the nervous and other body systems.
Opiates do not have clear indications for neuritis and neuropathy although they are widely prescribed for the pain but marijuana actually has been shown to relieve peripheral neuropathy due to HIV and diabetic neuropathy. THC has been useful for treating phantom pain with amputees, causalgias (another peripheral neuropathy condition), neuralgias, and conditions like trigeminal neuralgia. Medical marijuana has also found success with chronic cancer pain. A study at the University of Iowa found oral THC at 5 to 10 mg was as effective as 60mg of Codeine for terminal cancer pain relief.
One question that is obvious – Does marijuana alleviate pain simply because patients no longer care about it? Do the psychoactive effects of marijuana simply influence a patient’s attitude towards the pain and allow him or her to mask it out?

Cannabis/Cannabinoids/Neuropathic pain

5/5/2011 – Recent scientific articles reviewed the ability of cannabis and cannabinoids to treat pain, especially neuropathic pain. This may be new hope for doctors who are struggling to treat these conditions. Clinical trials on humans using cannabis in various forms (smoked, extracts, oral THC, synthetic analogues) were reviewed by different research teams. Three recent reviews of those human trials demonstrate that cannabis and cannabinoids are effective for treating certain types of chronic pain with acceptable side effects.

A review on the treatments for HIV neuropathic pain concluded that, “evidence of efficacy exists only for capsaicin, smoked cannabis and rhNGF (nerve growth factor). However, rhNGF is clinically unavailable and smoked cannabis cannot be recommended as routine therapy (Phillips et al).”

Meaning, the only medications that have been shown to effectively alleviate HIV/AIDS neuropathic pain are not available on the market. Notably “smoked cannabis” was shown to be effective for the treatment of HIV neuropathy, a condition that affects more than 40% of the estimated 33 million people currently living with HIV.

A University of Pennsylvania research team published a similar review concluding that, “there is strong evidence for a moderate analgesic effect in peripheral neuropathic and central pain conditions, and conflicting evidence for their use in nociceptive pain. For spasticity, most controlled studies demonstrate significant improvement. Adverse effects are not uncommon with cannabinoids, though most are not serious and self-limiting.”

Last but not least, researchers from Canada concluded, that “overall the quality of trials was excellent. Fifteen of the eighteen trials that met inclusion criteria demonstrated a significant analgesic effect of cannabinoid as compared to placebo, several reported significant improvements in sleep. There were no serious adverse effects. Adverse effects most commonly reported were generally well tolerated, mild to moderate in severity and led to withdrawal from the studies in only a few cases (Lynch et al).”

This team from was from Dalhousie University Department of Anesthesia and Pain Medicine, Hospital for Sick Children, University of Toronto. The researchers go on to say, “this systematic review of 18 recent good quality randomized trials demonstrates that cannabinoids are a modestly effective and safe treatment option for chronic non-cancer (predominantly neuropathic) pain.”

Traumatic pain is scratching your arm, banging your thumb with a hammer or post-operative pain (surgery). But neuropathic pain is something completely different because it is generated by diseases (Multiple Sclerosis, HIV/AIDS, amputation) or as a side effect from medication toxicity. Essentially the brain begins sending pain signals out to the body for no reason. Patients say they experience it as a burning or shooting pain sensation in their hands and feet at first. Neuropathic pain often progresses to become much more intense. Opiates do not seem to have any impact in certain groups of patients. Many HIV/AIDS patients use cannabis therapy already today; anecdotal reports have been confirmed with successful results in top-quality clinical trials.

Jahan Marcu is currently investigating the pharmacology of cannabinoid receptors. He was working at the California Pacific Medical Center Research Institute when exciting discoveries were made showing enhanced anti-cancer effects with THC and CBD from the Cannabis plant. The findings were published in the Journal of Molecular Cancer Therapeutics. In 2009 he received the Billy Martin Award from the International Cannabinoid Research Society (ICRS). Jahan is currently the vice-chair the Medical and Scientific Advisory Board at Americans for Safe Access (ASA). Contact: science { at } freedomisgreen.com

http://www.oliveny.org/blog/2011/05/cannabiscannabinoidsneuropathic-pain/