Opsumit Special Precautions

The benefit/risk balance of macitentan has not been established in patients with WHO class I functional status of pulmonary arterial hypertension.
Liver function: Elevations of liver aminotransferases (AST, ALT) have been associated with PAH and with endothelin receptor antagonists (ERAs). Opsumit is not to be initiated in patients with severe hepatic impairment or elevated aminotransferases (>3 x ULN) (see Dosage & Administration and Contraindications), and is not recommended in patients with moderate hepatic impairment. Liver enzyme tests should be obtained prior to initiation of Opsumit.
Patients should be monitored for signs of hepatic injury and monthly monitoring of ALT and AST is recommended. 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 (e.g., jaundice), Opsumit treatment should be discontinued.
Reinitiation of Opsumit may be considered following the return of hepatic enzyme levels to within the normal range in patients who have not experienced clinical symptoms of liver injury. The advice of a hepatologist is recommended.
Haemoglobin concentration: As with other ERAs, treatment with macitentan has been associated with a decrease in haemoglobin concentration (see Adverse Reactions). In placebo-controlled studies, macitentan-related decreases in haemoglobin concentration were not progressive, stabilised after the first 4-12 weeks of treatment and remained stable during chronic treatment. Cases of anaemia requiring blood cell transfusion have been reported with macitentan and other ERAs. Initiation of Opsumit is not recommended in patients with severe anaemia. It is recommended that haemoglobin concentrations be measured prior to initiation of treatment and tests repeated during treatment as clinically indicated.
Pulmonary veno-occlusive disease: Cases of pulmonary oedema have been reported with vasodilators (mainly prostacyclins) when used in patients with pulmonary veno-occlusive disease. Consequently, if signs of pulmonary oedema occur when macitentan is administered in patients with PAH, the possibility of pulmonary veno-occlusive disease should be considered.
Use in women of childbearing potential: Opsumit treatment should only be initiated in women of childbearing potential when the absence of pregnancy has been verified, appropriate advice on contraception provided, and reliable contraception is practiced (see Contraindications and Use in Pregnancy & Lactation). Women should not become pregnant for 1 month after discontinuation of Opsumit. Monthly pregnancy tests during treatment with Opsumit are recommended to allow the early detection of pregnancy.
Concomitant use with strong CYP3A4 inducers: In the presence of strong CYP3A4 inducers reduced efficacy of macitentan could occur. The combination of macitentan with strong CYP3A4 inducers (e.g., rifampicin, St. John's wort, carbamazepine, and phenytoin) should be avoided (see Interactions).
Concomitant use with strong CYP3A4 inhibitors: Caution should be exercised when macitentan is administered concomitantly with strong CYP3A4 inhibitors (e.g., itraconazole, ketoconazole, voriconazole, clarithromycin, telithromycin, nefazodone, ritonavir, and saquinavir) (see Interactions).
Patients with renal impairment: Patients with renal impairment may run a higher risk of experiencing hypotension and anaemia during treatment with macitentan. Therefore, monitoring of blood pressure and haemoglobin should be considered. There is no clinical experience with the use of macitentan in PAH patients with severe renal impairment. Caution is recommended in this population. There is no experience with the use of macitentan in patients undergoing dialysis, therefore Opsumit is not recommended in this population (see Pharmacology: Pharmacokinetics under Actions and Dosage & Administration).
Excipients: Opsumit tablets contain lactose. Patients with rare hereditary problems of galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.
Opsumit tablets contain lecithin derived from soya. If a patient is hypersensitive to soya, Opsumit must not be used (see Contraindications).
Effects on ability to drive and use machines: Macitentan may have a minor influence on the ability to drive and use machines. The clinical status of the patient and the adverse reaction profile of macitentan (such as headache, hypotension) should be kept in mind when considering the patient's ability to drive and use machines.
Male fertility: The development of testicular tubular atrophy in male animals was observed after treatment with macitentan (see Pharmacology: Toxicology: Preclinical safety data under Actions). The relevance of this finding to humans is unknown, but a deterioration of spermatogenesis cannot be excluded.
Use in Elderly: There is limited clinical experience with macitentan in patients over the age of 75 years, therefore Opsumit should be used with caution in this population (see Dosage & Administration).