Macitentan

SOURCE: UK SPC for Opsumit 10 mg film coated tablets (Great Britain) (https://www.medicines.org.uk/emc/product/5223/smpc), indicated in pulmonary arterial hypertension. PRESCRIBING RESTRICTION: treatment should only be initiated and monitored by a physician experienced in the treatment of PAH. The same 10 mg once-daily dose applies to adults and to paediatric patients aged less than 18 years weighing at least 40 kg. MISSED DOSE: take it as soon as possible and then take the next dose at the regularly scheduled time; do not take two doses at the same time. MONITORING: liver enzyme tests should be obtained prior to initiation, patients should be monitored for signs of hepatic injury and monthly monitoring of ALT and AST is recommended; discontinue if sustained, unexplained, clinically relevant aminotransferase elevations occur, or if elevations are accompanied by an increase in bilirubin >2 x ULN or by clinical symptoms of liver injury such as jaundice. Haemoglobin concentrations should be measured prior to initiation and repeated during treatment as clinically indicated; initiation is not recommended in patients with severe anaemia. HEPATIC IMPAIRMENT: based on pharmacokinetic 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 clinically significant elevated hepatic aminotransferases (>3 x ULN), and is not recommended in moderate hepatic impairment. ELDERLY: no dose adjustment is required over the age of 65 years. PAEDIATRIC (flat dose by weight band, not per-kg — so not expressed as a mg/kg dose): the 10 mg film-coated tablets are only recommended in paediatric patients weighing at least 40 kg, at the same 10 mg once daily. For paediatric patients weighing less than 40 kg, a lower strength of dispersible tablets of 2.5 mg is available — refer to the Opsumit dispersible tablets SmPC. Dosing and efficacy in children below 2 years of age have not been established and no recommendation on a posology can be made. Verify any under-18 use against a children's formulary. EFFICACY LIMIT: the benefit/risk balance has not been established in patients with WHO class I functional status of PAH. PULMONARY VENO-OCCLUSIVE DISEASE: if signs of pulmonary oedema occur, the possibility of pulmonary veno-occlusive disease should be considered.