Omeprazole Lopinavir

Proton pump inhibitors (marked effect) and H2-receptor antagonists (modest effect) reduce atazanavir levels. Other drugs that increase gastric pH are also predicted to reduce plasma levels of atazanavir. Fosamprenavir may be similarly affected (moderate effects seen with ranitidine), although antacids and esomeprazole had little effect in one study. Omeprazole decreases indinavir levels and an antacid modestly decreased tipranavir levels. Neither ranitidine nor omeprazole had any effect on darunavir/ritonavir or lopinavir/ritonavir levels. In contrast, cimetidine, ranitidine and omeprazole have been shown to increase saquinavir levels. 

In a randomised study in healthy subjects, omeprazole 40 mg once daily or ranitidine 150 mg one hour before breakfast had no effect on the relative bioavailability of either lopinavir or ritonavir when lopinavir/ritonavir 800/200 mg once daily was taken 30 minutes after breakfast, or when lopinavir/ritonavir 400/100 mg twice daily (30 minutes after a meal) was given 1.5 hours after the acid-reducing drug. The lopinavir/ritonavir was taken in a tablet form. ... 

Omeprazole and ranitidine do not appear to alter the pharmacokinetics of darunavir/ritonavir or lopinavir/ritonavir. 

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