See also How to Use section.

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 medications used to treat chronic hepatitis C (such as elbasvir/grazoprevir, glecaprevir/pibrentasvir), a certain combination HIV medication (elvitegravir/cobicistat/emtricitabine/tenofovir), indinavir, nevirapine, orlistat.

Other medications can affect the removal of atazanavir from your body, which may affect how atazanavir works. Examples include apalutamide, bosentan, efavirenz, etravirine, lumacaftor, certain rifamycins (such as rifampin, rifapentine), certain drugs used to treat seizures (such as carbamazepine, phenobarbital, phenytoin, primidone), St. John's wort, among others.

Atazanavir can slow down the removal of other medications from your body, which may affect how they work. Examples of affected drugs include certain alpha blockers (such as alfuzosin, silodosin), certain benzodiazepines (midazolam, triazolam), ergot alkaloids (such as dihydroergotamine, ergotamine), irinotecan, lomitapide, pimozide, certain drugs to treat erectile dysfunction-ED or pulmonary hypertension (such as avanafil, sildenafil), certain "statin" cholesterol drugs (lovastatin, simvastatin), salmeterol, among others.

Prescription and nonprescription drugs to treat heartburn, indigestion, or ulcers (including H2 blockers such as famotidine, proton pump inhibitors such as lansoprazole/omeprazole) reduce stomach acid and decrease the absorption of atazanavir. This may prevent atazanavir from working well. Ask your doctor or pharmacist how to use these medications safely.

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.