nevirapine: clinical use

Prescribing considerations

• Use only with other fully active antiretrovirals; assess treatment history and resistance results.
• The early treatment period carries the greatest risk of severe cutaneous and hepatic reactions; ensure patients understand symptom-triggered stopping and urgent review.
• Consider the increased hepatotoxicity risk associated with detectable viraemia and higher CD4 counts at initiation, particularly in women.
• Review hepatitis B or C coinfection, underlying liver disease, contraception and all interacting medicines before prescribing.
• Nevirapine is a strong enzyme inducer with clinically important interactions and delayed offset after withdrawal.

Contraindications and cautions

• Hypersensitivity to nevirapine or product excipients.
• Severe hepatic impairment.
• Markedly raised pretreatment transaminases until stabilised below the SmPC threshold.
• Re-administration after permanent withdrawal for severe rash, systemic hypersensitivity or clinical hepatitis caused by nevirapine.
• Re-administration after recurrent liver-test abnormalities on rechallenge.
• Concurrent St John's wort.

Monitoring

• Obtain liver function tests before treatment and monitor frequently during early therapy, then regularly thereafter.
• Perform prompt liver tests for rash, hypersensitivity features or symptoms suggesting hepatitis.
• Monitor any isolated rash closely and assess for systemic or mucosal involvement.
• Follow HIV viral load, treatment response and resistance risk as part of specialist combination therapy.
• Consider blood counts when used with zidovudine because granulocytopenia risk may increase.

Clinical pharmacology

Nevirapine is a non-competitive HIV-1 reverse-transcriptase inhibitor. It induces CYP3A and probably CYP2B6, producing numerous clinically significant interactions; it has no biologically significant activity against HIV-2 reverse transcriptase.

Formulation and product differences

• The immediate-release tablet has a score line solely to aid swallowing and must not be treated as providing equal halves.
• The prolonged-release tablet provides extended absorption and must be swallowed whole.
• The prolonged-release product is unsuitable for the SmPC-defined lead-in phase.
• Immediate-release and prolonged-release products have different missed-dose instructions and are not automatically interchangeable.
• Both selected tablet formulations contain lactose.

Modified-release tablet

Route: Oral

Strengths: 400 mg

Tablet

Route: Oral

Strengths: 200 mg