Effect of delta-9-tetrahydrocannabinol on intraocular pressure in humans

South Med J. 1977 Aug;70(8):951-4. doi: 10.1097/00007611-197708000-00016.


As early as 1971, it was noted that smoking marijuana lowered intraocular pressure. In this study one of the active components of marijuana, delta-9-tetrahydrocannabinol, was given intravenously to ten subjects with normal intraocular pressures. Two strengths were used--0.022 mg/kg of body weight and 0.044 mg/kg of body weight. Intraocular pressure was found to decrease as much as 51% of baseline normal with an average decrease of 37%. Heart rate increased in a range of 22% and 65% of the resting pulse. Respiratory rate was not affected. No analgesic properties were demonstrated by either cutaneous or periosteal stimulation. Anxiety levels were increased by delta-9-tetrahydrocannabinol over placebo and diazepam (Valium). The mechanism of action is still uncertain but it is believed by some workers to be similar to that of a beta-adrenergic stimulator.

Publication types

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

MeSH terms

  • Analgesia
  • Anxiety
  • Chemical Phenomena
  • Chemistry
  • Clinical Trials as Topic
  • Diazepam / administration & dosage
  • Diazepam / pharmacology
  • Dose-Response Relationship, Drug
  • Dronabinol / administration & dosage
  • Dronabinol / pharmacology*
  • Euphoria
  • Heart Rate / drug effects
  • Humans
  • Injections, Intravenous
  • Intraocular Pressure / drug effects*
  • Male
  • Placebos


  • Placebos
  • Dronabinol
  • Diazepam