Effect of cannabis on enzyme induction by phenobarbital.

Cannabis extracts in olive oil administered s.c. to male adult rats decreases oxidizing microsomal enzymes measured as TPNH disappearance and AHH activity in liver postmitochondrial fraction (93.06% and 25.54% maximum inhibition respectively in chronic treatments). Simultaneous administration of single doses of cannabis extracts (330 mg/kg s.c.) and phenobarbital (100 mg/kg i.p.) causes impairment of total microsomal oxidases (86.83% inhibition) and decreases AHH (31.86% inhibition), thus blocking the enzyme induction by phenobarbital.