PHARMACOKINETIC INTERACTION BETWEEN PROPRANOLOL AND THE HMG-COA REDUCTASE INHIBITORS PRAVASTATIN AND LOVASTATIN

1 Single oral 20 mg doses of the HMG-CoA reductase inhibitors pravastatin and lovastatin, with and without concomitant propranolol (40 mg twice daily), were administered to 16 healthy male subjects participating in a randomized, four-way crossover study. 2. Serum concentrations of total and active inhibitors were measured by bioassay and concentrations of pravastatin, two pravastatin metabolites and lovastatin acid were measured by gas chromatography/mass spectrometry. 3. Coadministration of propranolol with pravastatin reduced the mean area under the serum concentration-time curve (AUC) of total inhibitors by 23%, of active inhibitors by 20% and of pravastatin by 16%. 4. Coadministration of propranolol with lovastatin also resulted in decreases in the mean serum AUC of total inhibitors by 18%, of active inhibitors by 12% and of lovastatin acid by 13%. 5. These decreases in systemic drug concentrations may reflect enhanced drug first-pass hepatic clearance in the presence of propranolol. 6. The clinical significance of these changes is likely to be small.