Drug General Information (ID: DDI7UN4YSA)
Drug Name			Atazanavir		Drug Info		Dexlansoprazole		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Anti-Hiv Agents				Proton Pump Inhibitors
Structure

Mechanism of Atazanavir-Dexlansoprazole Interaction (Severity Level: Major)
Altered gastric pH Click to Show/Hide Mechanism Graph
Drug Name		Atazanavir				Dexlansoprazole
Mechanism		Gastric pH sensitive				Gastric alkalinizer
Key Mechanism Factor 1
		Factor Name		Gastric pH
		Factor Description		The normal pH range of gastric acid is between 1.5 and 3.5 and is highly acidic, consisting mainly of hydrochloric acid. Changes in the pH of the stomach can alter the absorption of drugs.
Mechanism Description		Decreased absorption of Atazanavir due to altered gastric pH caused by Dexlansoprazole

Recommended Action
Management		Given the risk of reduced viral susceptibility and resistance development associated with subtherapeutic antiretroviral drug levels, use of proton pump inhibitors is not recommended in treatment-experienced patients receiving atazanavir with or without ritonavir or cobicistat. In treatment-naive patients receiving atazanavir with ritonavir or cobicistat, it is recommended that the dose of the proton-pump inhibitor not exceed 20 mg/day of omeprazole, or equivalent, and doses should be separated by 12 hours. Atazanavir without ritonavir or cobicistat should not be coadministered with proton pump inhibitors in treatment-naive patients.

References
1	Cerner Multum, Inc. "Australian Product Information.".
2	Cerner Multum, Inc. "UK Summary of Product Characteristics.".
3	Drug interactions. Atazanavir and acid-reducing agents. TreatmentUpdate 18 (2006): 4. [PMID: 17209238]
4	Product Information. Evotaz (atazanavir-cobicistat). Bristol-Myers Squibb, Princeton, NJ.
5	Product Information. Reyataz (atazanavir). Bristol-Myers Squibb, Princeton, NJ.
6	Ray JE, Marriott D, Bloch MT, McLachlan AJ "Therapeutic drug monitoring of atazanavir: surveillance of pharmacotherapy in the clinic." Br J Clin Pharmacol 60 (2005): 291-9. [PMID: 16120068]
7	Durant J, Clevenbergh P, Garraffo R, Halfon P, Icard S, DelGiudice P, Montagne N, Schapiro JM, Dellamonica P "Importance of protease inhibitor plasma levels in HIV-infected patients treated with genotypic-guided therapy: pharmacological data from the Viradapt Study." Aids 14 (2000): 1333-9. [PMID: 10930147]