No pharmacokinetic drug-drug interaction between nevirapine and paclitaxel.

We have investigated the pharmacokinetics of nevirapine and paclitaxel in a patient who used both drugs concomitantly, as there are strong theoretical indications for a potential pharmacokinetic drug-drug interaction. Plasma concentrations of nevirapine (dose: 200 mg twice daily orally) and paclitaxel (dose: 100 mg/m(2) 3-h i.v. infusion) were determined in a HIV-1-infected patient with Kaposi's sarcoma. Since both drugs are metabolized via the same cytochrome P450 isoenzymes, investigation of a drug-drug interaction was considered important. We found that the plasma concentrations of nevirapine given together with paclitaxel were similar to those given without paclitaxel. The exposures to paclitaxel (AUC(0-infinity) = 3787 h.ng/ml) and its hydroxy metabolites when co-administered with nevirapine were comparable to the mean exposure to paclitaxel and its metabolites from eight historical controls (AUC(0-infinity) = 3614 h.ng/ml) treated with the same dose. No pharmacokinetic drug-drug interaction between nevirapine and paclitaxel could be demonstrated in our HIV-1-infected patient.