Atazanavir, With or Without Ritonavir, Should Not Be Coadministered With Proton Pump Inhibitors
December 20, 2004
Bristol-Myers Squibb has issued a Dear Healthcare Provider letter regarding important new pharmacokinetic data concerning the coadministration of Reyataz (atazanavir) and Norvir (ritonavir) with Prilosec (omeprazole). Omeprazole is a proton-pump inhibitor (PPI) for the treatment of acid-related diseases that works by suppressing gastric acid secretion.
The following observations were made from a randomized, open-label, multiple-dose drug interaction study.
A 76% reduction in atazanavir area under the concentration-time curve (AUC) and a 78% reduction in atazanavir trough plasma concentration (Cmin) were observed when Reyataz/ritonavir 300/100 mg was coadministered with omeprazole 40 mg.
Based on the study results:
Investigations regarding the potential drug interaction between Reyataz (atazanavir sulfate) and H2-Receptor antagonists (another type of gastric medication) when coadministered are ongoing. Until data are available, clinicians should note the following statements from the Reyataz Package Insert: "Reduced plasma concentrations of atazanavir are expected if H2-receptor antagonists are administered with Reyataz (atazanavir sulfate). This may result in loss of therapeutic effect and development of resistance. To lessen the effect of H2-receptor antagonists on atazanavir exposure, it is recommended that an H2-receptor antagonist and Reyataz be administered as far apart as possible, preferably 12 hours apart."
A copy of the complete letter is attached in PDF format.
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