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Plasma delta‐9‐tetrahydrocannabinol concentrations and clinical effects after oral and intravenous administration and smoking
Author(s) -
Ohlsson A,
Lindgren JE,
Wahlen A,
Agurell S,
Hollister L E,
Gillespie H K
Publication year - 1980
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.1980.181
Subject(s) - delta 9 tetrahydrocannabinol , plasma concentration , medicine , oral administration , tetrahydrocannabinol , anesthesia , absorption (acoustics) , marijuana smoking , cannabis , pharmacology , cannabinoid , substance abuse , physics , receptor , polysubstance dependence , psychiatry , acoustics
Delta‐9‐tetrahydrocannabinol (THC) was given intravenously, by smoking, and by mouth to 11 healthy subjects. Plasma profiles of THC after smoking and intravenous injection were similar whereas plasma levels after oral doses were low and irregular, indicating slow and erratic absorption. Based on AUC 0–360 min systemic availability of THC after smoking was estimated to be 18 ± 6%. Oral THC in a chocolate cookie provided systemic availability of 6 ± 3%. Of the two major clinical signs of cannabis intoxication, reddened conjunctivae persisted for as long as THC levels were above 5 ng/ml, and tachycardia was a less reliable measurement of prevailing THC levels or “high.” The time courses of plasma concentrations and clinical “high” were of the same order for intravenous injection and smoking, with prompt onset and steady decline over a 4‐hr period. The appearance of “high” lagged behind the increase in plasma concentrations, suggesting that brain concentrations were increasing as plasma concentrations decreased. After oral THC, the onset of clinical effects was much slower and lasted longer, but effects occurred at much lower plasma concentrations than after the other two methods of administration. Clinical Pharmacology and Therapeutics (1980) 28, 409–416; doi: 10.1038/clpt.1980.181