IT SHOULD NOT BE ADMINISTERED CONCURRENTLY WITH TERFENADINE, CISAPRIDE, ASTEMIZOLE, TRIAZOLAM, MIDAZOLAM OR ERGOT DERIVATIVES, BECAUSE COMPETITION FOR CYP3A BY SAQUINAVIR COULD RESULT IN INHIBITION OF THE METABOLISM OF THESE DRUGS AND CREATE THE POTENTIAL FOR SERIOUS AND/OR LIFE-THREATENING REACTIONS SUCH AS CARDIAC ARRHYTHMIAS OR PROLONGED SEDATION .
COADMINISTRATION OF PROTEASE INHIBITORS, INCLUDING SAQUINAVIR, WITH ST. JOHN'S WORT IS EXPECTED TO SUBSTANTIALLY DECREASE PROTEASE INHIBITOR CONCENTRATIONS AND MAY RESULT IN SUB-OPTIMAL LEVELS OF SAQUINAVIR AND LEAD TO LOSS OF VIROLOGIC RESPONSE AND POSSIBLE RESISTANCE TO SAQUINAVIR OR TO THE CLASS OF PROTEASE INHIBITORS.
CLINICALLY SIGNIFICANT DRUG INTERACTIONS WHICH DECREASE SAQUINAVIR PLASMA CONCENTRATIONS
HIV NON-NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITORS NEVIRAPINE
ANTIMYCOBACTERIAL AGENTS RIFABUTIN , RIFAMPIN
CLINICALLY SIGNIFICANT DRUG INTERACTIONS
WHICH INCREASE SAQUINAVIR PLASMA CONCENTRATIONS
ANTIBIOTICS CLARITHROMYCIN
HIV PROTEASE INHIBITORS INDINAVIR, RITONAVIR, NELFINAVIR
HIV NON-NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITORS DELAVIRDINE
ANTIFUNGAL AGENTS KETOCONAZOLE
OTHER POTENTIAL DRUG INTERACTIONS
ANTICONVULSANTS: CARBAMAZEPINE, PHENOBARBITAL, PHENYTOIN MAY DECREASE SAQUINAVIR PLASMA CONCENTRATIONS
CORTICOSTEROIDS: DEXAMETHASONE MAY DECREASE SAQUINAVIR PLASMA CONCENTRATIONS ( TOPICAL STEROIDS IF APPLIED ON BROKEN SKIN OR OVER LARGE AREAS MAY BE ABSORBED SUBSTENTIALLY TO CAUSE SYSTEMIC EFFECTS ). COADMINISTRATION OF SAQUINAVIR, A CYP3A4 INHIBITOR, WITH SILDENAFIL RESULTED IN A 140% INCREASE IN SILDENAFIL C MAX AND A 210% INCREASE IN SILDENAFIL AUC.