Effect of eucalyptol (1,8-cineole) on the metabolism of other drugs in rats and in man

Eucalyptol (1,8-cineole) given by aerosol for 4 days to rats decreases the plasma and/or brain levels of amphetamine, zoxazolamine, pentobarbital and aminopyrine given 24 hr after the last aerosol. However, the levels of plasma phenylbutazone were not affected by previous treatment with eucalyptol (1,8-cineole). Eucalyptol (1,8-cineole) pretreatment increases the rate of disappearance of plasma aminopyrine and the rate of urinary excretion of 4-aminoantipyrine, a metabolite of aminopyrine. This effect may be due to the increased rate of formation of 4-aminoantipyrine. The disappearance of aminopyrine from plasma was enhanced in 4 out of 5 volunteers submitted for 10 days to treatment with eucalyptol (1,8-cineole) aerosol.