Protease inhibitors associated with a variety of hypersensitivity events (some severe), including rash, anaphylaxis (rare), angioedema, bronchospasm, erythema multiforme, and/or Stevens-Johnson syndrome (rare). Generally recommended to discontinue treatment if severe rash or moderate symptoms accompanied by other systemic symptoms occur. May cause fat redistribution. Patients may develop immune reconstitution syndrome resulting in occurrence of inflammatory response to indolent or residual opportunistic infection. Increases in total cholesterol and triglycerides reported. Ritonavir associated with AV block due to prolongation of PR interval (use caution with drugs which prolong the PR interval). Use with caution in cardiomyopathy, ischemic heart disease, pre-existing conduction abnormalities, or structural heart disease (may be at increased risk of conduction abnormalities (e.g. second- or third-degree AV block)). Changes in glucose tolerance, hyperglycemia, exacerbation of diabetes, DKA, and new-onset diabetes mellitus reported in patients receiving protease inhibitors. Use with caution in hemophilia A or B (increased bleeding events, including spontaneous skin hematoma and hemarthrosis, reported during protease inhibitor therapy). May cause hepatitis, jaundice, and/or exacerbation of pre-existing hepatic dysfunction (use with caution in underlying hepatic disease, such as hepatitis B or C or cirrhosis). Use with caution in increased triglycerides (pancreatitis observed). Ritonavir may interact with many medications, resulting in potentially serious and/or life-threatening adverse events. Use with caution in patients taking strong CYP3A4 inhibitors, moderate or strong CYP3A4 inducers and major CYP3A4 substrates. Not recommended for use with alfuzosin, amiodarone, cisapride, ergot derivatives, flecainide, lovastatin, midazolam, pimozide, propafenone quinidine, simvastatin, St. John’s wort, triazolam, or voriconazole.