VIRAMUNE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VIRAMUNE (VIRAMUNE).
Non-nucleoside reverse transcriptase inhibitor (NNRTI); binds directly to HIV-1 reverse transcriptase, causing allosteric inhibition and blocking RNA-dependent and DNA-dependent DNA polymerase activities.
| Metabolism | Primarily metabolized by CYP3A4 and CYP2B6; undergoes hydroxylation and glucuronidation. Also a CYP3A4 inducer. |
| Excretion | Renal: <5% unchanged; urinary metabolites: ~80% (glucuronides, hydroxylated metabolites); fecal: ~10%. |
| Half-life | Terminal elimination half-life: 25-30 hours (single dose); 20-25 hours at steady state due to autoinduction. Clinical context: Autoinduction of CYP3A4 reduces half-life after multiple doses. |
| Protein binding | 60% bound to plasma proteins (albumin and lipoproteins). |
| Volume of Distribution | 1.2-1.5 L/kg, indicating extensive extravascular distribution. |
| Bioavailability | Oral: >90% (tablet and oral suspension). |
| Onset of Action | Oral: Rapid absorption; peak plasma concentrations at 2-4 hours. Clinical effect (HIV RNA reduction) typically seen within 1-2 weeks. |
| Duration of Action | Duration of therapeutic effect: 12 hours (due to recommended twice-daily dosing). Clinical notes: Continuous suppression requires consistent adherence. |
200 mg orally once daily for 14 days, then 200 mg twice daily; alternatively, 400 mg extended-release once daily for 14 days, then 400 mg extended-release once daily.
| Dosage form | SUSPENSION |
| Renal impairment | No dose adjustment required for GFR ≥30 mL/min. For GFR <30 mL/min or ESRD not on dialysis, use with caution; no specific dose recommendation available. |
| Liver impairment | Child-Pugh Class A: No dose adjustment. Child-Pugh Class B: Contraindicated. Child-Pugh Class C: Contraindicated. |
| Pediatric use | For patients ≥3 months of age: 150 mg/m² orally once daily for 14 days, then 150 mg/m² twice daily; maximum 400 mg per day. |
| Geriatric use | No specific dose adjustment; monitor closely due to increased risk of adverse effects (e.g., hepatotoxicity, rash). |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for VIRAMUNE (VIRAMUNE).
| Breastfeeding | Not recommended due to potential for HIV transmission via breast milk. Nevirapine is excreted into human breast milk; M/P ratio approximately 0.7. In HIV-positive mothers, alternatives should be considered to avoid infant exposure. |
| Teratogenic Risk | FDA Pregnancy Category B. No evidence of teratogenicity in humans based on cohort studies; animal studies show no fetal harm at systemic exposures similar to human therapeutic levels. First trimester exposure not associated with increased major malformations. Second and third trimester exposure: no specific fetal risks identified, but monitor for mitochondrial toxicity (theoretical). |
■ FDA Black Box Warning
Severe, life-threatening hepatotoxicity including fulminant and cholestatic hepatitis, hepatic necrosis, and hepatic failure. Fatal cases have been reported, especially within the first 18 weeks of therapy. Also, severe skin reactions including Stevens-Johnson syndrome, toxic epidermal necrolysis, and hypersensitivity reactions can occur.
| Serious Effects |
["Hypersensitivity to nevirapine or any component of the formulation.","Use with St. John's wort (reduces nevirapine levels).","Not recommended for post-exposure prophylaxis (PEP) due to risk of hepatotoxicity."]
| Precautions | ["Hepatotoxicity: monitor hepatic enzymes closely, especially during first 18 weeks; discontinue if severe hepatitis occurs.","Severe skin reactions: discontinue if rash with systemic symptoms or blistering.","Immune reconstitution syndrome: may occur during initial treatment.","Resistance: cross-resistance with other NNRTIs.","Drug interactions: induces CYP3A4, reducing levels of many drugs (e.g., oral contraceptives, methadone, warfarin)."] |
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| Fetal Monitoring | Monitor maternal hepatic function (ALT, AST) at baseline and every 2 weeks for first 12 weeks, then monthly; watch for rash (including Stevens-Johnson syndrome). Fetal monitoring: standard antenatal ultrasound; assess for growth restriction if hepatotoxicity develops. Postnatal: monitor infant for nevirapine-related adverse effects (e.g., hepatotoxicity) if exposed. |
| Fertility Effects | No known adverse effects on male or female fertility; limited human data. In animal studies, no impairment of fertility observed at clinically relevant doses. |