Delavirdine and Invirase

In the database of official manuals used in the service creation an interaction registered by statistical results of studies was found, which can either lead to negative consequences for the patient health or strengthen a mutual positive effect. A doctor should be consulted to address the issue of joint drug administration.

Using saquinavir together with delavirdine may increase the effects of saquinavir. Contact your doctor if you experience sore throat, headache, rash, increased urination or extreme thirst, easy bruising or bleeding, fever, chills, cough, nausea, stomach pain, loss of appetite, dark urine, clay-colored stools, or jaundice (yellowing of the skin or eyes). If your doctor does prescribe these medications together, you may need a dose adjustment or special test to safely use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

ADJUST DOSE: Coadministration with delavirdine may significantly increase the plasma concentrations of saquinavir. The mechanism is delavirdine inhibition of saquinavir metabolism via CYP450 3A4. According to the delavirdine labeling, coadministration of delavirdine (400 mg three times a day) and saquinavir (soft gel capsule, or SGC, 1000 mg three times a day) for 28 days increased the mean peak plasma concentration (Cmax), area under the concentration-time curve (AUC) and trough plasma concentration (Cmin) of saquinavir by 98%, 121% and 199%, respectively, compared to administration of saquinavir SGC 1200 mg three times a day without delavirdine. Saquinavir had no apparent effect on the pharmacokinetics of delavirdine based on comparison with historical data. When administered with saquinavir mesylate (i.e., hard gelatin capsule, or HGC), delavirdine has been reported to increase saquinavir plasma levels 5-fold.

MANAGEMENT: Given the magnitude of interaction, a reduction of saquinavir SGC dosage should be considered during coadministration with delavirdine. Product labeling for the individual agents states that appropriate dosages for this combination with respect to safety and efficacy have not been established, although some HIV experts recommend that saquinavir SGC be given at 800 mg three times a day with the standard dosage of delavirdine. No dosage recommendations are available for saquinavir HGC or for saquinavir (either SGC or HGC) in combination with ritonavir. Patients receiving saquinavir with delavirdine should be monitored for toxicity such as elevations in liver function tests and undue gastrointestinal disturbances.

Delavirdine

Generic Name: delavirdine

Brand name: Rescriptor

Synonyms: n.a.

What is Delavirdine?

Invirase

Generic Name: saquinavir

Brand name: Invirase, Fortovase

Synonyms: n.a.

What is Invirase?