Dilantin Infatabs and Viramune XR

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 phenytoin together with nevirapine may decrease the effects of nevirapine. Contact your doctor if your condition changes. 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.

MONITOR: Coadministration with phenytoin may decrease the plasma concentrations of nevirapine. The proposed mechanism is phenytoin induction of nevirapine metabolism via CYP450 3A4. In eight healthy, nonpregnant women, administration of a single 200 mg dose of nevirapine with phenytoin 184 mg daily for 3 days or 7 days resulted in a median decrease of 19.0 hours (range 11.4 to 25.4 hours) and 16.9 hours (range 10.9 to 37.4 hours), respectively, in the elimination half-life of nevirapine compared to administration alone. The decrease in nevirapine half-life led to faster undetectable nevirapine levels (median reduction in time to undetectable levels was 7 days and 8.5 days, respectively), which the authors of the study suggest might reduce the risk of resistance development in pregnant women treated with single-dose nevirapine for prevention of vertical HIV transmission. However, the effect of the interaction on nevirapine during prolonged administration as part of highly active antiretroviral therapy (HAART) is unknown.

MANAGEMENT: Antiretroviral effects and serum drug concentrations of nevirapine should be monitored closely during coadministration with phenytoin.

Dilantin Infatabs

Generic Name: phenytoin

Brand name: Dilantin, Phenytek, Dilantin Infatabs, Phenytoin Sodium, Prompt

Synonyms: Dilantin

What is Dilantin Infatabs?

Viramune XR

Generic Name: nevirapine

Brand name: Viramune, Viramune XR

Synonyms: n.a.

What is Viramune XR?