nevirapine hemihydrate: clinical use

Prescribing considerations

• Use only within an active combination regimen selected using treatment history and resistance results.
• The first 18 weeks require close review for rash, hypersensitivity and hepatotoxicity; risk is greatest early in treatment.
• Assess baseline viral load, CD4 count and liver-risk factors, including hepatitis B or C and pre-existing hepatic disease.
• Higher CD4 counts with detectable HIV-1 RNA are associated with increased hepatotoxicity risk when initiating treatment.
• Review all medicines for enzyme-induction interactions and assess contraceptive reliability.

Contraindications and cautions

• Hypersensitivity to nevirapine or an excipient.
• Severe hepatic impairment or markedly elevated pretreatment transaminases until stabilised.
• Rechallenge after nevirapine-related severe rash, systemic hypersensitivity or clinical hepatitis.
• Rechallenge after recurrent significant liver abnormalities.
• Concurrent St John’s wort.
• The suspension must not be used in hereditary fructose intolerance and is unsuitable for certain rare sugar-intolerance disorders.

Monitoring

• Obtain liver-function tests before treatment and monitor closely during the early treatment period and regularly thereafter.
• Repeat liver tests promptly if rash or symptoms of hepatitis or hypersensitivity develop.
• Monitor HIV viral response and resistance risk, particularly after adherence problems or treatment interruption.
• Monitor blood counts when combined with zidovudine, especially in children or people with limited marrow reserve.
• In children receiving suspension, reassess weight or body surface area frequently.

Clinical pharmacology

Nevirapine is a non-competitive HIV-1 reverse-transcriptase inhibitor. It is well absorbed orally, extensively metabolised mainly through CYP3A pathways, induces CYP3A and CYP2B6, and undergoes autoinduction. Parent-medicine renal elimination is minor.

Formulation and product differences

• The selected product is a white to off-white oral suspension containing nevirapine as the hemihydrate.
• Shake gently and measure with an oral syringe; tablets and suspension have comparable bioavailability under the conditions studied.
• The suspension contains sucrose, sorbitol and parabens; these affect suitability for some patients and may cause delayed allergy.
• Use the suspension within six months of first opening; no special storage conditions are required.

Oral suspension

Route: Oral

Strengths: 50 mg/5 mL