A9-THC is readily absorbed when marijuana is smoked. Pharmacological effects are produced rapidly and generally peak within 30 minutes of the onset of smoking. The dynamics of smoking (number of puffs, spacing, hold time, and lung capacity) substantially influence how much drug is absorbed. Although oral ingestion of marijuana produces similar pharmacological effects, A9-THC is absorbed more slowly than by smoking. Impairment on various performance measures related to driving skills has been demonstrated immediately following marijuana smoking and up to 24 hours thereafter. Generally, behavioral and physiological effects return to baseline levels 4 to 6 hours after usage. Blood concentrations of A9-THC peak prior to drug-induced effects. This time discordance between blood concentrations of A9-THC and effects has made it difficult to establish a meaningful relationship between blood concentrations and effects.
A9-THC is rapidly distributed to all tissues despite being tightly bound by plasma proteins. A9-THC is a highly lipophilic substance and so accumulates in tissue high in lipid content. Traces of A9-THC have been found in adipose tissue more than 30 days after the subject smoked a single joint. The terminal half-life of A9-THC in plasma ranges from 18 hours to 4 days.
Was this article helpful?