Dronabinol pharmacokinetics

The effects of smoked marijuana (3.95% tetrahydrocannabinol up to three cigarettes per day) and oral dronabinol (2.5 mg tds) on the pharmacokinetics of indinavir 800 mg 8-hourly (n = 28) have been evaluated in a randomized, placebo-controlled study in HIV-infected patients (148). On day 14, marijuana reduced the 8-hour AUC of indinavir by 15%, the Cmax by 14%, and the Cm n... 

In a recent controlled cannabinoid administration study of THC-containing hemp oils and dronabinol, the pharmacokinetics and pharmacodynamics of oral THC were evaluated. Up to 14.8 mg of THC was ingested by six volunteers each day in three divided doses with meals for five consecutive days (Nebro et al. 2004). There was a 10-day washout phase between each of the five dosing sessions. THC was quantified in plasma by solid-phase extraction followed by positive chemical ionization GC/MS. THC and 11-OH-THC were rarely detected in plasma following the two lowest doses of 0.39 and 0.47 mg/day THC, while peak plasma... 

B. Pharmacokinetics. Only about 10-20% of ingested dronabinol is absorbed, with onset of effects within 30-60 minutes and peak absorption at 2-4 hours. Metabolized by hydroxylation to active and inactive metabolites. Elimination half-life is 20-30 hours, but may be longer in chronic users. 

In 9 HIV-positive patients on a stable regimen containing indinavir (mostly 800 mg every 8 hours), smoking a cannabis cigarette (3.95% tetrahydrocannabinol) three times a day before meals for 14 days resulted in a median 14% decrease in AUC and maximum level and a 34% decrease in minimum indinavir level. However, only the change in maximum level was statistically significant. Similarly, dronabinol 2.5 mg three times daily for 14 days had no significant effect on indinavir pharmacokinetics. ... 

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