Kinetic study of smoking marijuana

Abstract

Six subjects each smoked a 1% marijuana cigarette and 2 hr later smoked a second one. Plasma levels of delta-9-tetrahydrocannabinol were measured for 9 hr with a radioimmunoassay. Heart rate and self-reported "high" were measured for 2 hr after each cigarette. All three measures showed a rapid increase after the start of smoking with Cmax occurring before the end of smoking. There was a strong correlation between decrease in heart rate and plasma levels from 10 min after smoking until 120 min. All pharmacodynamic response measures returned to baseline values within approximately 2 hr.

Delta-9-tetrahydrocannabinol (THC) serum concentrations and pharmacological effects in males after smoking a combination of tobacco and cannabis containing up to 69 mg THC

“…The pharmacokinetics of THC have been repeatedly studied (Lindgren et al 1981; Barnett et al 1982;PerezReyes et al 1982;Ohlsson et al 1982;Huestis et al 1992a;Ramaekers et al 2006). When smoking a cannabis cigarette, THC is already detectable in plasma seconds after the first puff.…”

Pharmacokinetics of Cannabinoids

“…There was a tendency for peak concentrations to be lower for the women, but there was no significant difference in the area under the concentrationtime curve (AUC) (28,29). THC plasma levels decreased rapidly after cessation of smoking and, at 2 h after smoking, were below 5 ng/mL; 15 min after reaching the maximum, mean concentrations declined by approximately 50% (26,30).…”

“…The acute effect on heart rate has also been used for such modelling (30). Dose and plasma concentration versus response for possible therapeutic applications are ill-defined, except for some information obtained for oral dosing with dronabinol for its limited indications (19).…”

“…Such correlations of THC pharmacokinetics are complicated by the emergence of active metabolites, particularly 11-hydroxy-THC (47,49), which attains higher plasma concentrations after oral than inhalation doses. In one study (30), six volunteers smoked 1% by weight cigarettes with an average weight of 894 mg (total THC dose 8.9 mg), and then smoked a second cigarette after 2 h. Plasma THC concentrations, heart rate and self-reported 'high' profiles were documented. Similar psychological 'highs' occurred after both cigarettes, but less heart rate acceleration was found for the second cigarette.…”

Profils cinétiques du Δ9-tétrahydrocannabinol, du 11-hydroxy-Δ9-tétrahydrocannabinol et de l'acide 11-nor-Δ9-tétrahydrocannabinol- 9-carboxylique chez le sujet volontaire sain après administration orale de décoctions de cannabis ou de dronabinol

“…La pharmacocinêtique des cannabinoïdes est également très compliquée et encore mal comprise. Des modèles à 2, 3, 4, voire 5 compartiments ont été utilisés pour décrire les cinétiques du THC (28)(29)(30). Des demi-vies des phases terminales d'élimination du THC et du THCCOOH très longues (> 24 heures) ont été calculées en utilisant ces modèles.…”