Pharmacokinetic interaction between ezetimibe and lovastatin in healthy volunteers*

SUMMARY

Background: Ezetimibe (Zetia†) is a novel inhibitor of intestinal absorption of cholesterol that is approved for the treatment of primary hypercholesterolemia. In a separate pilot study, co-administration of ezetimibe and lovastatin resulted in a significant pharmacodynamic interaction, leading to an additive reduction in LDL-C. The current study was designed to further investigate the potential for pharmacokinetic interaction between ezetimibe and lovastatin.

Methods: This was a randomized, open-label, 3-way crossover study in 18 healthy adult volunteers. All subjects received the following treatments orally once daily for 7 days: ezetimibe 10 mg, lovastatin 20 mg, or ezetimibe 10 mg plus lovastatin 20 mg. Plasma samples obtained on day 7 were evaluated for steady-state pharmacokinetics of ezetimibe (unconjugated), total ezetimibe (ezetimibe and ezetimibe-glucuronide conjugate), lovastatin, and β-hydroxylovastatin.

Results: Co-administration of ezetimibe with lovastatin did not affect the pharmacokinetics of ezetimibe. There were no significant differences in the exposure to total ezetimibe, ezetimibe-glucuronide and ezetimibe after co-administration with lovastatin vs. ezetimibe given alone. Co-administration of ezetimibe with lovastatin had no significant effect on the exposure to either lovastatin or β-hydroxylovastatin. The point estimates based on the log-transformed C_max and AUC values for lovastatin and β-hydroxylovastatin were 113% and 119%, respectively, for co-administration of ezetimibe with lovastatin vs. lovastatin administration alone. Co-administration therapy with ezetimibe and lovastatin was safe and well tolerated.

Conclusions: Ezetimibe did not significantly affect the pharmacokinetics of lovastatin or β-hydroxylovastatin and vice versa. Co-administration of ezetimibe and lovastatin is unlikely to cause a clinically significant pharmacokinetic drug interaction.

Key words: :

• Cholesterol-lowering drugs
• Drug interactions
• Ezetimibe
• Lovastatin
• Pharmacodynamics
• Pharmacokinetics
• Statins