Nevirapine dosage

Concomitant medication with inducers of drug c/earance. Patients on rifampin should receive caspofungin 70 mg/day. Patients on nevirapine, efavirenz, carbamazepine, dexamethasone, or phenytoin may require an increase in dosage to caspofungin 70 mg/day. 

Lopinavir/Ritonavir Pediatric Dosage Without Efavirenz or Nevirapine... 

Dosage adjustment Discontinue nevirapine if patients experience severe rash or a rash accompanied by constitutional findings (see Warnings). Patients experiencing rash during the 14-day lead-in period of 200 mg/day (4 mg/kg/day in children) should not have their nevirapine dose increased until the rash has resolved. 

The majority of rashes associated with nevirapine occur within the first 6 weeks of initiation of therapy. Instruct patients not to increase the 200 mg/day (4 mg/kg/day in children) dosage if any rash occurs during the 2-week lead-in dosing period until the rash resolves. 

HIV infection (in combination with other antiretrovirals) PO 800 mg (two 400-mg capsules) q8h. Dosage adjustments when given concomitantly Delavirdine, itraconazole, ketoconazok Reduce dose to 600 mg q8h. Efavirenz-. Increase dose to 1,000 mg q8h. Lopinavir/ritonavir Reduce dose to 600 mg twice a day. Nevirapine-. Increase dose to 1,000 mgqSh. Rifabutin-. Reduce rifabutin by lA and increase indinavir to 1,000 mg q8h. Ritonavir 100-200 mg twice a day and indinavir 800 mg twice a day or ritonavir 400 mg twice a day and indinavir 400 mg twice a day. 

In a multiple dose study, 21 children aged 3 months to 15 years were treated with nevirapine in dosages of 7.5-400 mg/m /day for up to 168 days (18). When it was intended to use dosages over 240 mg/m /day they were pretreated with a lower dosage (120 mg/m /day) for 28 days to reduce the risk of rash. However, a rash developed in one child after 2 weeks of treatment with nevirapine at a dosage of 240 mg/m /day, resolved on withdrawal, and recurred on rechallenge with a single dose of 120 mg/m. ... 

Delavirdine. Dclavirdine (Rescriptor)" must be u.sed with at least two additional antiretroviral agents to treat HI V-I infections. The oral ab.sorption of dclavirdine is rapid, and peak plasma concentrations develop in I hour. Extensive mctaboli.sni occurs in the liver by cytochrome P-450 (CYP) isozyme 3A (CYP 3A) or pos.sibly CYP 2D6. Bioavailability is 85%. Unlike nevirapine, which is 48%. protein bound, dclavirdine is more than 98% protein bound. The half-life is 2 to II hours, and elimination is 44% in feces. 51% in urine, and lc.ss than 5% unchanged in urine. Dclavirdine induces its own mctaboli.sm." Oral dosage forms are. supplied as a 200-mg capsule and a lOO-ing tablet. 

Information seems to be limited to these three cases, but it would be prudent to monitor prothrombin times and INRs in any patient if warfarin and nevirapine are used concurrently, being alert for the need to increase the warfarin dosage (possibly twofold). Information about other oral anticoagulants seems to be lacking, but if the suggested mechanism is correct, all coumarins would be expected to interact to some extent. 

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