The pharmacologic effects of daily marijuana smoking in humans.

Abstract Six healthy male, paid volunteers smoked one NIDA cigarette containing 1.0% THC each day for 13 consecutive days. They were tested before and after the period of drug administration by the following procedure: the subjects smoked on NIDA marijuana cigarette containing 1.0% THC followed 15 minutes later by the intravenous infusion of 52 μg/min of deutered THC for 50 minutes. The THC plasma concentrations, ratings of “high” and heart rate effects procedured by the combined drug administation were measured, and absolute bioavailability of smoked THC was calculated on Days 1 and 22. Statistical analyses indicate that the only significant changes induced by daily marijuana exposure were in cardioaccelerator.