EFFECTS OF TETRAHYDROCANNABINOL ON ARTERIAL AND INTRA-OCULAR HYPERTENSION

  • 1 January 1979
    • journal article
    • research article
    • Vol. 17  (5) , 191-196
Abstract
Clinical studies were conducted to determine the relationship between simultaneous changes in heart rate, blood pressure and intraocular pressure in systemic normotensive (N = 8) and hypertensive (N = 8) open-angle glaucoma patients (N = 16) after inhalation of tetrahydrocannabinol (THC). Insignificant changes occurred in arterial and ocular pressures after placebo pertubations. The functional responses after 2.8% THC inhalation in setting normotensive and hypertensive patients included invariable increases in heart rate (range 20-62 beats/min > control) followed by substantial decreases in systolic pressure (range 12-52 mmHg < control), diastolic pressure (range 6-28 mmHg < control) and intraocular pressure (range 6-21 mmHg < control). The intensity and duration (3-4 h) of the arterial and ocular pressure responses to THC were greater in hypertensives than in normotensive patients. The salient observation after THC inhalation was that the changes in ocular pressure paralleled the changes in blood pressure in each glaucoma patient. Apparently the positive chronotropic response to THC tends to maintain cardiac output which limits further decreases in blood pressure and the capillary filtration of aqueous humor decreases or the reabsorption of aqueous humor increases because of the systemic hypotensive effect attending THC inhalation.