VIRAMUNE XR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VIRAMUNE XR (VIRAMUNE XR).
Non-nucleoside reverse transcriptase inhibitor (NNRTI) that binds directly to HIV-1 reverse transcriptase, causing enzyme inhibition and preventing viral RNA-dependent DNA polymerization.
| Metabolism | Extensively metabolized by cytochrome P450 (CYP) 3A, with some contribution from CYP2B6. Forms 2-hydroxy- and 3-hydroxy-nevirapine metabolites. |
| Excretion | Renal (81% as metabolites, <5% unchanged), fecal (10% as metabolites). |
| Half-life | Terminal elimination half-life 25-30 hours after multiple doses; clinical context: allows once-daily dosing after lead-in phase. |
| Protein binding | 60% bound to albumin, 34% bound to other plasma proteins (alpha-1-acid glycoprotein and lipoproteins); total 94% bound. |
| Volume of Distribution | 1.42 L/kg; indicates extensive tissue distribution, including into CSF (50% of plasma concentration). |
| Bioavailability | Oral: 90% relative to immediate-release formulation; no absolute oral bioavailability change with extended-release formulation. |
| Onset of Action | Oral: therapeutic effect on HIV replication within 1-2 weeks; peak plasma concentrations at 4 hours. |
| Duration of Action | 24 hours with once-daily dosing; clinical notes: requires steady-state lead-in with immediate-release nevirapine to reduce rash risk. |
400 mg orally once daily for 14 days lead-in, then 400 mg orally twice daily.
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | No dose adjustment required for GFR >=30 mL/min. For GFR <30 mL/min, not recommended due to lack of data. |
| Liver impairment | Child-Pugh A: 200 mg orally once daily for 14 days lead-in, then 200 mg orally twice daily. Child-Pugh B: contraindicated. Child-Pugh C: contraindicated. |
| Pediatric use | For patients >=3 years and >=10 kg: 7 mg/kg (max 200 mg) orally once daily for 14 days lead-in, then 7 mg/kg (max 200 mg) orally twice daily. Administer as immediate-release. |
| Geriatric use | No specific dose adjustment; monitor for increased adverse effects due to age-related reduced clearance. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for VIRAMUNE XR (VIRAMUNE XR).
| Breastfeeding | Nevirapine is excreted into human breast milk. Milk-to-plasma (M/P) ratio is approximately 0.7. Breastfeeding is not recommended for HIV-infected mothers in resource-rich settings to avoid postnatal HIV transmission. If breastfeeding is unavoidable, monitor infant for toxicity (especially hepatotoxicity) and ensure maternal HIV viral suppression. |
| Teratogenic Risk | VIRAMUNE XR (nevirapine) is classified as FDA Pregnancy Category B. No evidence of teratogenicity in animal studies. Placental transfer occurs. Limited human data: no increased risk of fetal malformations observed in first trimester. In third trimester, use is associated with hepatotoxicity risk and potential for maternal-fetal transmission of HIV if resistance develops. Pharmacokinetic changes in pregnancy may reduce efficacy if standard dosing is used. |
■ FDA Black Box Warning
Severe, life-threatening hepatotoxicity, including fulminant and fatal hepatitis, and severe skin reactions, including Stevens-Johnson syndrome, toxic epidermal necrolysis, and hypersensitivity reactions. Therapy should not be initiated in women with CD4+ count >250 cells/mm³ or men with CD4+ count >400 cells/mm³ due to increased risk of hepatotoxicity.
| Serious Effects |
["Hypersensitivity to nevirapine or any formulation excipients","Moderate to severe hepatic impairment (Child-Pugh Class B or C)","Use as post-exposure prophylaxis","Use in women with CD4+ count >250 cells/mm³ or men with CD4+ count >400 cells/mm³ unless benefit outweighs risk"]
| Precautions | ["Hepatic adverse events: monitor liver function tests closely during first 18 weeks of therapy; discontinue if clinical hepatitis or transaminase elevations with signs of hypersensitivity occur.","Severe skin reactions: discontinue if rash is severe or accompanied by systemic symptoms; do not restart after severe reaction.","Immune reconstitution syndrome","Resistance: cross-resistance with other NNRTIs may occur.","CYP3A induction: may reduce efficacy of coadministered drugs metabolized by CYP3A."] |
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| Fetal Monitoring | Monitor maternal hepatic function (AST, ALT) prior to and regularly during therapy, especially in first 18 weeks. Monitor for rash (Stevens-Johnson syndrome). Fetal monitoring: ultrasound for growth and anatomy if used in pregnancy. Check HIV viral load and CD4+ count at regular intervals to assess treatment efficacy. Assess infant for HIV status postnatally and monitor for nevirapine-related adverse effects (liver function, rash). |
| Fertility Effects | No known effects on fertility. Nevirapine does not impair reproductive function in animal studies. No human data on fertility impairment. Use in HIV-infected individuals not associated with reduced fertility. |