PREZISTA CO-ADMINISTERED WITH RITONAVIR IS AN INHIBITOR OF CYP3A AND CYP2D6. CO-ADMINISTRATION OF PREZISTA AND RITONAVIR WITH DRUGS THAT ARE PRIMARILY METABOLIZED BY CYP3A AND CYP2D6 MAY RESULT IN INCREASED PLASMA CONCENTRATIONS OF SUCH DRUGS, WHICH COULD INCREASE OR PROLONG THEIR THERAPEUTIC EFFECT AND ADVERSE EVENTS.
DARUNAVIR AND RITONAVIR ARE METABOLIZED BY CYP3A. DRUGS THAT INDUCE CYP3A ACTIVITY WOULD BE EXPECTED TO INCREASE THE CLEARANCE OF DARUNAVIR AND RITONAVIR, RESULTING IN LOWERED PLASMA CONCENTRATIONS OF DARUNAVIR AND RITONAVIR. CO-ADMINISTRATION OF DARUNAVIR AND RITONAVIR AND OTHER DRUGS THAT INHIBIT CYP3A MAY DECREASE THE CLEARANCE OF DARUNAVIR AND RITONAVIR AND MAY RESULT IN INCREASED PLASMA CONCENTRATIONS OF DARUNAVIR AND RITONAVIR
Alfuzosin Potential for serious and/or life-threatening reactions such as hypotension.
Ergot Derivatives Dihydroergotamine, Ergonovine, Ergotamine, Methylergonovine Potential for serious and/or life-threatening events such as acute ergot toxicity characterized by peripheral vasospasm and ischemia of the extremities and other tissues.
GI Motility Agent Cisapride Potential for serious and/or life-threatening reactions such as cardiac arrhythmias.
Neuroleptic Pimozide Potential for serious and/or life-threatening reactions such as cardiac arrhythmias.
Sedative/hypnotics Orally administered Midazolam, Triazolam Triazolam and orally administered midazolam are extensively metabolized by CYP3A. Co-administration of triazolam or orally administered midazolam with DARUNAVIR/ritonavir may cause large increases in the concentrations of these benzodiazepines. Potential for serious and/or life-threatening events such as prolonged or increased sedation or respiratory depression.
Herbal Products St. John's Wort (Hypericum perforatum) Patients taking DARUNAVIR/ritonavir should not use products containing St. John's wort because co-administration may result in reduced plasma concentrations of darunavir. This may result in loss of therapeutic effect and development of resistance.
HMG-CoA Reductase Inhibitors Lovastatin, Simvastatin Potential for serious reactions such as myopathy including rhabdomyolysis.
Antimycobacterial Rifampin Rifampin is a potent inducer of CYP450 metabolism. DARUNAVIR/ritonavir should not be used in combination with rifampin, as this may cause significant decreases in darunavir plasma concentrations. This may result in loss of therapeutic effect to DARUNAVIR.
PDE-5 inhibitor Sildenafil for treatment of pulmonary arterial hypertension A safe and effective dose for the treatment of pulmonary arterial hypertension has not been established with DARUNAVIR/ritonavir. There is an increased potential for sildenafil-associated adverse events (which include visual disturbances, hypotension, prolonged erection, and syncope).