Macitentan

Source: UK SPC (eMC) for Opsumit 10mg film coated tablets (Great Britain), §4.2 (https://www.medicines.org.uk/emc/product/5223/smpc). Indication context: pulmonary arterial hypertension (PAH). Treatment should only be initiated and monitored by a physician experienced in the treatment of PAH. The §4.2 posology heading reads 'Adults and paediatric patients aged less than 18 years of age weighing at least 40 kg' and gives the same 10 mg once-daily dose for both. MISSED DOSE: take as soon as possible, then take the next dose at the regularly scheduled time; do not take two doses at the same time. METHOD OF ADMINISTRATION: the film-coated tablets are not breakable and are to be swallowed whole with water; may be taken with or without food. ELDERLY: no dose adjustment is required in patients over the age of 65 years. HEPATIC IMPAIRMENT: based on PK data no dose adjustment is required in mild, moderate or severe hepatic impairment, but there is no clinical experience in PAH patients with moderate or severe hepatic impairment; Opsumit must not be initiated in patients with severe hepatic impairment or with clinically significant elevated hepatic aminotransferases (>3 × ULN), and is not recommended in moderate hepatic impairment. HAEMOGLOBIN: initiation is not recommended in patients with severe anaemia. PREGNANCY: treatment should only be initiated in women of childbearing potential once the absence of pregnancy has been verified, contraception advice given and reliable contraception practised. PRODUCT STRENGTH SCOPE: this bundle covers the 10 mg film-coated tablet only. §4.5 was not retrieved in this bundle — the interactions listed come from the §4.4 paragraph on strong CYP3A4 inducers (itself truncated at the source-fetch limit) and from the US FDA label §7; verify the full §4.5.

NOT A PER-KG DOSE — dosePerKg is deliberately null; do not compute a weight-based dose from this entry. UK SPC §4.2 gives a fixed dose in a weight band: paediatric patients aged less than 18 years weighing at least 40 kg receive 10 mg once daily, the same as adults, and 'The 10 mg film-coated tablets are only recommended in paediatric patients weighing at least 40 kg.' For paediatric patients weighing less than 40 kg a lower strength of dispersible tablets of 2.5 mg is available and the separate Opsumit dispersible tablets SPC must be consulted — that product is not in this bundle. 'Dosing and efficacy of macitentan in children below 2 years of age have not been established... no recommendation on a posology can be made.' Verify any under-18 use against a children's formulary.