Drug interactions
Calcium carbonate + Fosamprenavir
Severity: Moderate
Calcium carbonate and Fosamprenavir: moderate 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
Antacids reduced amprenavir exposure modestly in studies of fosamprenavir. The reduction could weaken antiviral efficacy if doses are given together.
What this interaction means in plain words
Calcium carbonate and Fosamprenavir can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Antacid-induced rise in gastric pH and possible binding reduce absorption of amprenavir, the active metabolite.
What to do
Give fosamprenavir at least 2 hours before or 1 hour after the antacid. Monitor HIV viral load if separation is not feasible.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Calcium carbonate
Frequently asked questions
Can I take Calcium carbonate with Fosamprenavir?
MediHelp rates the interaction as moderate. Calcium carbonate and Fosamprenavir can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Antacids reduced amprenavir exposure modestly in studies of fosamprenavir. The reduction could weaken antiviral efficacy if doses are given together.
How serious is the interaction between Calcium carbonate and Fosamprenavir?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Give fosamprenavir at least 2 hours before or 1 hour after the antacid. Monitor HIV viral load if separation is not feasible.
What other medicines interact with Calcium carbonate?
MediHelp also lists interactions of Calcium carbonate with, for example, Acalabrutinib, Alendronate, Amlodipine-hydrochlorothiazide-valsartan. The full list is on the Calcium carbonate page.
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