Cannabinoids effect on HIV-1 viral load and appetite

Simon Collins, HIV i-Base

Anecdotal benefits to appetite stimulation and stress relief (amongst other effects) ensure that a widespread use of marijuana amongst HIV positive people in California (where there is also an established movement for legalisation for medical use).

Donald Abrams and colleagues at University of California, San Francisco initiated a safety study based on a possible interaction with ARVs via CYP p450 or immune modulation via the CB2 receptor. The study looked at whether cannabis is associated with an effect on viral load, as well as short-term effects on endocrine function, appetite, energy intake and expenditure, body weight and composition.

In this randomised, partially blinded, placebo controlled 21-day study, 67 people (90% men) were randomised to either smoke cannabis, take oral dronabinol (a oral formulation of the active ingredient in cannabis) or take an oral placebo. All subjects were on a ‘stable’ combination, although only around 50% of people had undetectable viral loads at entry and 10% had counts about 10,000. Entry requirements for the study included previous use of marijuana – although not for the month prior to enrolment.

After three weeks, the study found small decreases in viral load (around 0.15 log reductions) in both the smoked and oral cannabis groups – although the broad definition of ‘stable’ treatment for entry criteria makes an interpretation of this result difficult. Still, it was an interesting finding, and most importantly viral load did not increase. People on the placebo arm had a reduction in viral load of 0.06 log. What was more significant was the average calorie intake – 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.

Table 1

Calories/day Weight (kg)
Mean (95% CI) Change (95% CI)
Marijuana 4771 (4630, 4911) +3.51 (2.17, 4.86)
Dronabinol 4124 (4017, 4230) +3.18 (2.24, 4.11)
Placebo 3619 (3545, 3692) +1.30 (0.57, 2.03)

Three people left the study (1 receiving marijuana, two receiving dronabinol) due to neuropsychiatric symptoms. No adverse events were reported in the placebo arm.


  1. Abrams D, Leiser R et al – Short-term effects of cannabinoids on HIV-1 viral load. XIII International AIDS Conference, Durban, 9-14 July 2000. Abstract LpPeB 7053.

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