Drug interactions
Atazanavir + Famotidine
Severity: Major
Atazanavir and Famotidine: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Atazanavir needs an acidic stomach for dissolution, and famotidine raises gastric pH. This can substantially lower atazanavir levels and risk virologic failure and resistance.
What this interaction means in plain words
Atazanavir and Famotidine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Atazanavir belongs to Anti Virals; Famotidine belongs to Gastrointestinal Tract.
Why it happens
Famotidine raises gastric pH, reducing the pH-dependent solubility and absorption of atazanavir.
What to do
Give atazanavir with or at least 10 hours after the H2 blocker, and use ritonavir boosting at labeled doses; limit the H2 blocker dose to labeled maximums.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Famotidine
Other interactions of Atazanavir
- Alfuzosin + Atazanavir Contraindicated
- Atazanavir + Avanafil Contraindicated
- Atazanavir + Dronedarone Contraindicated
- Atazanavir + Eletriptan Contraindicated
- Atazanavir + Eplerenone Contraindicated
- Atazanavir + Ergotamine Contraindicated
Frequently asked questions
Can I take Atazanavir with Famotidine?
MediHelp rates the interaction as major. Atazanavir and Famotidine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Atazanavir needs an acidic stomach for dissolution, and famotidine raises gastric pH. This can substantially lower atazanavir levels and risk virologic failure and resistance.
How serious is the interaction between Atazanavir and Famotidine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Give atazanavir with or at least 10 hours after the H2 blocker, and use ritonavir boosting at labeled doses; limit the H2 blocker dose to labeled maximums.
What other medicines interact with Famotidine?
MediHelp also lists interactions of Famotidine with, for example, Dasatinib, Infigratinib, Itraconazole. The full list is on the Famotidine page.
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