nevirapine anhydrate: clinical use

Prescribing considerations

• Use only with other active antiretroviral agents and select the combination using treatment history and resistance results.
• Early treatment is the highest-risk period for serious cutaneous and hepatic reactions; ensure patients understand prodromal symptoms and routes for urgent review.
• Assess hepatic status and clinically relevant interacting medicines before prescribing.
• Prolonged-release tablets contain lactose and must be swallowed intact.

Contraindications and cautions

• Hypersensitivity to nevirapine or an excipient.
• Severe hepatic impairment or markedly elevated pretreatment aminotransferases until stabilised below the specified SmPC threshold.
• Re-exposure after nevirapine-related severe rash, systemic hypersensitivity or clinical hepatitis requiring permanent discontinuation.
• Re-exposure after recurrent liver-test abnormalities associated with rechallenge.
• Concurrent St John’s wort.

Monitoring

• Clinical review for rash, hypersensitivity and hepatic symptoms, particularly during early treatment.
• Liver-function tests at baseline and regularly thereafter, with additional testing when symptoms or abnormalities occur.
• HIV viral load and treatment response; investigate adherence, interactions and resistance if virological failure occurs.
• Haematological parameters when combined with zidovudine, especially where bone-marrow reserve is limited.

Clinical pharmacology

Nevirapine is an allosteric HIV-1 NNRTI. It is extensively metabolised through cytochrome P450 pathways, principally CYP3A, and induces CYP3A and potentially CYP2B6. Autoinduction increases its clearance during continued exposure; renal elimination of unchanged nevirapine is minor.

Formulation and product differences

• Prolonged-release tablets provide extended absorption and lower peak concentrations than immediate-release tablets.
• Prolonged-release tablets must not be divided, crushed or chewed.
• Immediate-release and prolonged-release formulations are not interchangeable without specialist assessment.
• Alternative formulations are needed for people unable to swallow the prolonged-release tablet.

Modified-release tablet

Route: Oral

Strengths: 400 mg