Short-term effects of cannabinoids in patients with HIV-1 infection: a randomized, placebo-controlled clinical trial

Ann Intern Med. 2003 Aug 19;139(4):258-66. doi: 10.7326/0003-4819-139-4-200308190-00008.


Background: Cannabinoid use could potentially alter HIV RNA levels by two mechanisms: immune modulation or cannabinoid-protease inhibitor interactions (because both share cytochrome P-450 metabolic pathways).

Objective: To determine the short-term effects of smoked marijuana on the viral load in HIV-infected patients.

Design: Randomized, placebo-controlled, 21-day intervention trial.

Setting: The inpatient General Clinical Research Center at the San Francisco General Hospital, San Francisco, California.

Participants: 67 patients with HIV-1 infection.

Intervention: Participants were randomly assigned to a 3.95%-tetrahydrocannabinol marijuana cigarette, a 2.5-mg dronabinol (delta-9-tetrahydrocannabinol) capsule, or a placebo capsule three times daily before meals.

Measurements: HIV RNA levels, CD4+ and CD8+ cell subsets, and pharmacokinetic analyses of the protease inhibitors.

Results: 62 study participants were eligible for the primary end point (marijuana group, 20 patients; dronabinol group, 22 patients; and placebo group, 20 patients). Baseline HIV RNA level was less than 50 copies/mL for 36 participants (58%), and the median CD4+ cell count was 340 x 109 cells/L. When adjusted for baseline variables, the estimated average effect versus placebo on change in log10 viral load from baseline to day 21 was -0.07 (95% CI, -0.30 to 0.13) for marijuana and -0.04 (CI, -0.20 to 0.14) for dronabinol. The adjusted average changes in viral load in marijuana and dronabinol relative to placebo were -15% (CI, -50% to 34%) and -8% (CI, -37% to 37%), respectively. Neither CD4+ nor CD8+ cell counts appeared to be adversely affected by the cannabinoids.

Conclusions: Smoked and oral cannabinoids did not seem to be unsafe in people with HIV infection with respect to HIV RNA levels, CD4+ and CD8+ cell counts, or protease inhibitor levels over a 21-day treatment.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Administration, Oral
  • CD4 Lymphocyte Count
  • CD4-Positive T-Lymphocytes / drug effects
  • CD8-Positive T-Lymphocytes / drug effects
  • Cannabinoids / adverse effects
  • Cannabinoids / pharmacology*
  • Dronabinol / pharmacology
  • Drug Interactions
  • Female
  • HIV Infections / immunology
  • HIV Infections / virology*
  • HIV Protease Inhibitors / pharmacokinetics
  • HIV Protease Inhibitors / pharmacology*
  • HIV-1 / drug effects*
  • Humans
  • Indinavir / pharmacokinetics
  • Indinavir / pharmacology
  • Male
  • Nelfinavir / pharmacokinetics
  • Nelfinavir / pharmacology
  • RNA, Viral / blood
  • Viral Load*


  • Cannabinoids
  • HIV Protease Inhibitors
  • RNA, Viral
  • Indinavir
  • Dronabinol
  • Nelfinavir