Zaleplon rifampicin

RIFAMPICIN ZALEPLON, ZOLPIDEM, ZOPICLONE 1 levels of these hypnotics Induction of CYP3A4-mediated metabolism Watch for poor response to these agents... 

Zaleplon is primarily metabolized by aldehyde oxidase and use with inhibitors of this enzyme, such as cimetidine, may result in increased plasma concentrations of zaleplon. Zaleplon is also partly metabolized by the cytochrome P450 isoenzyme CYP3A4 and, consequently, caution is advised when zaleplon is given with drugs that are substrates for, or potent inhibitors of, this isoenzyme. Cimetidine is also an inhibitor of CYP3A4 and thus inhibits both the primary and secondary metabolic pathways of zaleplon. Use with rifampicin or other potent enzyme-inducing drugs may accelerate the metabolism of zaleplon and reduce its plasma concentrations [40]. 

Rifampicin significantly induces the metabolism of zaleplon and reduces its sedative action (15), although the effect is less than the effect of rifampicin on triazolam or midazolam, probably because they are more exclusively metabolized by CYP3A4. 

Zaleplon, zolpidem and zopiclone are metabolised by several cytochrome CYP450 isoenzymes and it has been suggested that because of this, other drugs which affect a particular isoenzyme such as CYP3A4, may have less effect on their metabolism. However, their pharmacokinetics are affected by potent inducers such as rifampicin and by inhibitors such as the azole antifungals. Buspirone undergoes CYP3A4-mediated metabolism in the liver. 

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