efavirenz + emtricitabine + tenofovir disoproxil fumarate: clinical use

Prescribing considerations

• Confirm sustained virological suppression, treatment history and absence of significant resistance to all components.
• Not recommended in moderate or severe renal impairment because component adjustments cannot be made within the fixed combination.
• Assess psychiatric and seizure history, liver disease, fracture risk, interacting medicines and QT-risk factors.
• Establish hepatitis B status; withdrawal in HIV/HBV co-infection can cause severe hepatitis exacerbation.
• Discuss pregnancy testing and effective contraception where relevant.

Contraindications and cautions

• Hypersensitivity to an active substance or excipient.
• Severe hepatic impairment.
• Relevant congenital or acquired QT prolongation, major proarrhythmic clinical factors or contraindicated QT-prolonging medicines.
• Concomitant St John’s wort, voriconazole, elbasvir/grazoprevir and specified medicines whose altered metabolism could cause serious toxicity.

Monitoring

• HIV viral load and clinical response, particularly after switching therapy.
• Renal function and serum phosphate before treatment and periodically, with closer monitoring for renal risk factors or nephrotoxic medicines.
• Liver function, particularly with pre-existing liver disease or viral hepatitis.
• Neuropsychiatric symptoms, neurological function and seizure control where relevant.
• Blood lipids, glucose and clinically relevant bone symptoms.
• Clinical and laboratory follow-up after stopping treatment in people with HIV and hepatitis B.

Clinical pharmacology

Efavirenz is an HIV-1 non-nucleoside reverse transcriptase inhibitor and an inducer of CYP3A4, CYP2B6 and UGT1A1. Intracellular emtricitabine triphosphate and tenofovir diphosphate inhibit reverse transcriptase and terminate viral DNA chains; emtricitabine and tenofovir are predominantly renally eliminated.

Formulation and product differences

• The selected preparation is a film-coated fixed-combination tablet intended to be swallowed whole.
• Component-specific adjustment is not possible; separate preparations are required if an individual component must be changed.
• The selected tablet is essentially sodium-free.

Tablet

Route: Oral

Strengths: 600 mg + 200 mg + 245 mg