Cannabis for Treatment of HIV-Related Peripheral Neuropathy

The full results of this study appear in the February 13, 2007 issue of the journal Neurology. Below is a brief summary of these results.
Dr. Abrams and the Community Consortium conducted a study to evaluate the safety and effectiveness of smoked marijuana to treat pain caused by HIV-related peripheral neuropathy (injury to the nerves that supply feelings to your arms and feet). The study evaluated whether marijuana had an effect on pain relief. Marijuana was compared to a placebo; a cigarette that smells and tastes like marijuana but has no active ingredients (THC).
The study evaluated both ongoing neuropathic pain (clinical pain) and temporary pain induced by applying heat and capsaicin (ingredient that makes red peppers hot) cream to a small area of the skin (experimental pain).
Fifty-five patients were randomized and 50 completed the entire trial. Smoked marijuana reduced daily pain by 34% compared to 17% with placebo. The study concluded that 52% of patients who smoked marijuana had a greater than 30% reduction in pain compared to 24% in the placebo group. In this study, smoked marijuana was well tolerated and effectively relieved chronic neuropathic pain from HIV-related peripheral neuropathy. The findings are comparable to clinically proven oral drugs for chronic neuropathic pain.


INVESTIGATOR: Donald Abrams, M.D.
STUDY LOCATION: University of California, San Francisco
PROJECT TITLE: Cannabis for Treatment of HIV-Related Peripheral Neuropathy
PROJECT TYPE: Clinical Study

SMOKED CANNABIS THERAPY FOR HIV-RELATED PAINFUL PERIPHERAL

NEUROPATHY: RESULTS OF A RANDOMIZED, PLACEBO-CONTROLLED

CLINICAL TRIAL

 

Donald I. Abrams, Cheryl A. Jay, Hector Vizoso, Starley B. Shade, Haatem Reda, Scott Press,

Mary Ellen Kelly, Michael Rowbotham, and Karin Petersen

 

The University of California San Francisco, San Francisco, California 94110, USA

INTRODUCTION: There is significant evidence that cannabinoids may be involved in the modulation

of pain, especially of neuropathic origin. HIV-related painful peripheral neuropathy is a significant

medical problem with unsatisfactory treatment options. Based on the effects of cannabinoids in preclinical

models of neuropathic pain and anecdotal case reports, a controlled trial of smoked cannabis was

conducted.

METHODS: Following a 16 patient open-label pilot proof-of-concept phase that suggested a beneficial

clinical effect of seven days of smoked cannabis, a follow-on randomized, placebo-controlled trial was

conducted. Fifty participants with painful HIV-related neuropathy and baseline pain scores > 3 on a 10

point visual analog scale were admitted to the General Clinical Research Center for a 7-day inpatient

stay. Participants smoked one 3.56% tetrahydrocannabinol containing cigarette or a matching placebo

three times daily for five days. In addition to the effect of smoked cannabis on the subjects’ chronic

clinical pain, the impact on an experimental heat/capsaicin pain model was also evaluated. The primary

endpoints were the reduction and relative reduction in neuropathic pain as assessed by average daily

pain scores as well as the effect of smoking on acute experiemntal pain. A >30% reduction in pain was

considered to be significant for this analysis. Reduction in experimental pain was a secondary outcome

measure.

RESULTS: Fifty of the 56 randomized participants (43 men, 7 women, mean age 48 years) completed

the placebo-controlled trial; 25 on each arm. Patients had an average of 6 years of neuropathic pain. In

17 cases the neuropathy was felt to be secondary to HIV alone, in 26 secondary to HIV medications and

to both in 7. Baseline characteristics were well-matched across study arms. Thirteen of the 25 patients

who were randomized to marijuana cigarettes reported greater then 30% reduction in pain during the

intervention phase, compared with 6 of the 25 patients receiving placebo cigarettes (p=0.04). The pain

reduction was greater in the group receiving marijuana (34%) than in the group receiving placebo

(16.7%). The marijuana group also experienced a similar significant reduction in response to the

experimental pain model compared to placebo recipients. Adverse events were not appreciated in this

trial.

CONCLUSION: Smoked marijuana is effective in reducing chronic ongoing neuropathic pain as well

as acute pain in the experimental pain model. The magnitude of the response of the neuropathic pain is

similar to what is seen with gabapentin, a widely used therapeutic intervention for HIV neuropathy.

Acknowledgements: The University of California Center for Medicinal Cannabis Research and NIH

Grant 5-MO1-RR00083

http://www.cmcr.ucsd.edu/images/pdfs/Abrams_abs_2.pdf

http://www.cmcr.ucsd.edu/images/pdfs/Abrams_2007.pdf