Elimination of alfentanil delivered by infusion is not altered by the chronic administration of atorvastatin.

Background And Objective: Statins are prescribed for patients with hypercholesterolemia. Atorvastatin is metabolized by cytochrome P4503A4 and inhibits P4503A4 activity in vitro. Alfentanil is a potent opioid used in clinical anaesthetic practice and is also metabolized by P4503A4. This study tested the hypothesis that chronic atorvastatin administration inhibits the metabolism of alfentanil.

Methods: Sixteen patients undergoing elective surgery were studied as matched pairs. One member of each pair was maintained on standard doses of atorvastatin for at least 4 months. Each patient received an alfentanil bolus (80 microg kg(-1)) intravenously (i.v.), followed by an alfentanil infusion (0.67 microg kg(-1) min(-1)) for 90 min. Serial plasma alfentanil concentrations were measured using gas chromatography-nitrogen phosphorous detection. Pharmacokinetic parameters were calculated using two-compartment linear modelling.

Results: One patient and the corresponding match were excluded from the analysis. The elimination half-life of alfentanil was similar in the control and atorvastatin groups (98.8 +/- 12.4 versus 98.3 +/- 11.3 min, respectively). The clearance (Cl), volume of distribution at steady-state (Vdss) and area under the curve (AUC) were similar in the two groups (Cl = 0.20 (+/- 0.06) and 0.22 (+/- 0.04) L min(-1), Vdss = 0.38 (+/- 0.07) and 0.39 (+/- 0.07) L kg(-1), AUC = 0.05 (+/- 0.02) and 0.04 (+/- 0.01) mg min mL(-1)).

Conclusions: Concurrent atorvastatin administration does not alter the pharmacokinetics of alfentanil in patients undergoing elective surgery.