THC: Study of Its Effect on Viral Load

Short Term Effects of Cannabinoids (THC; marijuana cigarettes) on HIV-1 Viral Load

For background information, Donald Abrams, MD, University of California at San Francisco, discussed in his late breaker poster at Durban how canniboid use could potentially alter HIV viral load levels by 2 mechanisms--immune modulation or interactions with protease inhibitor because both share cytochrome P450 metabolism pathways. Anecdotal benefits to appetite stimulation and stress relief (amongst other effects) encourage use of marijuana amongst HIV-positive people living in California, and this gave impetus to Abrams to conduct this study.

This was a randomized, partially blinded, placebo controlled 21-day inpatient study. HIV positive patients on a stable indinavir or nelfinavir regimen were randomized to one of three arms--3.95% THC marijuana cigarette, oral dronabinol (an oral form of the active ingredient in marijuana), or an oral placebo. HIV viral load was measured often--twice at baseline and at weeks 2, 5, 8, 11, 14, 17, 19, and 21. The HIV viral load was <50 copies/ml for 37 (55%) of patients at baseline and the median CD4 was 300. However, 7 individuals had viral load >10,000 copies/ml, and 13 had viral load 500-9999 copies/ml. Prior use of marijuana was required to qualify for the study but no use was permitted for the month prior to beginning the study. Sixty-three patients completed the 21-day hospital stay. On average, patients who smoked or took oral dronabinol had greater decreases in viral load between day 0 and day 21 than patients on placebo, but the difference was not very much (-0.15 log, p=0.11, vs.-0.19 log, p=0.13), after adjusting for baseline viral load, CD4 count, and protease inhibitor. 12 of 62 individuals had increased viral loads of <1 log: 5 (25% in the marijuana arm, 2 (10%) in the dronabinol arm, and 5 (25%) in the placebo arm. Three individuals discontinued from study (1 marijuana, 2 oral dronabinol) due to neuro-psychiatric symptoms. No adverse events were reported in the placebo arm.

Interestingly, the average calorie intake was higher in the marijuana smoking, and oral dronabinol arms than in the placebo armŮ 4700,4100 and 3600 calories a day in the marijuana, dronabinol and placebo arms respectively. This lead to an average weight gain of 3.5,3.1 and 1.3 kgs over the three week study period. So, patients receiving smoked or oral marijuana gained more weight than those receiving placebo.