baloxavir marboxil: clinical use

Prescribing considerations

• Confirm uncomplicated influenza or an appropriate post-exposure prevention indication and follow current official recommendations.
• Check availability, local formulary status and supply without delaying an appropriate alternative antiviral.
• Evidence is limited in severe influenza; seek specialist advice if illness is severe, response is poor or antiviral resistance is suspected.
• Safety and efficacy are not established below 3 weeks of age, in preterm neonates or in severe hepatic impairment.

Contraindications and cautions

• Hypersensitivity to baloxavir marboxil or any excipient.
• The tablets contain lactose and should not be used in patients with galactose intolerance, total lactase deficiency or glucose-galactose malabsorption.

Monitoring

• Assess clinical response, particularly in children and immunosuppressed patients, where treatment-emergent resistance is a greater concern.
• Consider virological testing and specialist input if clinical response is poor or resistance is suspected.

Clinical pharmacology

Baloxavir marboxil is a prodrug hydrolysed to baloxavir, which inhibits the influenza polymerase acidic subunit’s cap-dependent endonuclease. Baloxavir is mainly metabolised through UGT1A3, with a minor CYP3A4 contribution, and is highly protein bound.

Formulation and product differences

• The selected product has two film-coated tablet strengths differentiated by size and tablet marking.
• Both tablet strengths contain lactose and are essentially sodium-free.
• A non-tablet formulation may be required if tablets cannot be swallowed; use its product-specific prescribing information.

Tablet

Route: Oral

Strengths: 40 mg, 80 mg