Atazanavir and Staxyn

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.

Atazanavir may increase the blood levels and effects of vardenafil. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if your condition changes or you experience nausea, shortness of breath, dizziness, lightheadedness, fainting, visual disturbances, ringing in the ears, vision or hearing loss, chest pain or tightness, irregular heartbeat, and/or priapism (prolonged and painful erection unrelated to sexual activity), as these may be signs and symptoms of excessive vardenafil levels. 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 atazanavir may increase the plasma concentrations of vardenafil. The proposed mechanism is atazanavir inhibition of CYP450 3A4, the isoenzyme primarily responsible for the metabolic clearance of vardenafil. The interaction has not been specifically studied but is presumed based on data available for ritonavir, another protease inhibitor. According to vardenafil labeling, coadministration of ritonavir (600 mg twice a day) and vardenafil (5 mg) resulted in a 13-fold increase in the peak plasma concentration (Cmax) and a 49-fold increase in the area under the concentration-time curve (AUC) of vardenafil. The half-life of vardenafil, normally 4 to 5 hours, was significantly prolonged to 26 hours. To what extent this interaction may occur with atazanavir is unknown, as it is a considerably weaker inhibitor of CYP450 3A4 than ritonavir.

MANAGEMENT: Caution and dose reductions of vardenafil is recommended. If vardenafil is to be used in patients on ritonavir-boosted atazanavir therapy, the dose should not exceed 2.5 mg every 72 hours. Patients should be monitored for adverse events during concomitant use, and advised to promptly notify their doctor if they experience pain or tightness in the chest or jaw, irregular heartbeat, nausea, shortness of breath, visual disturbances, syncope, or prolonged erection (greater than 4 hours).

Atazanavir

Generic Name: atazanavir

Brand name: Reyataz

Synonyms: n.a.

What is Atazanavir?

Staxyn

Generic Name: vardenafil

Brand name: Levitra, Staxyn

Synonyms: n.a.

What is Staxyn?