Amprenavir; Atazanavir/Antacids; Buffered Formulations Interactions

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

Antacids and buffered medicines (such as some didanosine products) increase the pH (decrease the acidity) of your stomach. Atazanavir needs an acidic environment to be absorbed by your body. Antacids can also affect how much amprenavir your body absorbs.

What might happen:

The amount of amprenavir or atazanavir in your blood may decrease and it may not work as well against your HIV infection.

What you should do about this interaction:

Take your amprenavir 1 hour before or 1 hour after any antacid or buffered medicine, such as didanosine.Take your atazanavir 2 hours before or 1 hour after any antacid or buffered medicine, such as didanosine.Your healthcare professionals (e.g. doctor or pharmacist) may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.

  • 1.Reyataz (atazanavir sulfate) US prescribing information. Bristol-Myers Squibb Company May, 2017.
  • 2.Reyataz (atazanavir sulfate) Australian product information. Bristol-Myers Squibb Pharmaceuticals January 8, 2004.
  • 3.Agenerase (amprenavir) Oral Solution US prescribing information. GlaxoSmithKline May, 2005.