Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug include: certain HIV protease inhibitors (such as lopinavir, tipranavir), orlistat.

Other medications can affect the removal of fosamprenavir from your body, which may affect how fosamprenavir works. Examples include apalutamide, etravirine, rifampin, St. John's wort, among others.

Fosamprenavir can speed up or slow down the removal of other medications from your body, which may affect how they work. Examples of affected drugs include alpha blockers (such as alfuzosin), certain benzodiazepines (midazolam, triazolam), ergot alkaloids (such as dihydroergotamine, ergotamine), fluticasone, pimozide, ranolazine, rivaroxaban, drugs to treat erectile dysfunction-ED or pulmonary hypertension (such as sildenafil, vardenafil), certain drugs to treat irregular heartbeat (such as flecainide, propafenone), certain "statin" cholesterol drugs (lovastatin, simvastatin), salmeterol, among others.

This medication may decrease the effectiveness of hormonal birth control such as pills, patch, or ring. This could cause pregnancy. Discuss with your doctor or pharmacist if you should use reliable backup birth control methods while using this medication. Also tell your doctor if you have any new spotting or breakthrough bleeding, because these may be signs that your birth control is not working well.