New medicines
Thelin
Composition: Sitaxentan sodium.
Presentation: Film-coated tablet 100mg.
Class: Endothelin A receptor antagonist.
Indications: Treatment of patients with pulmonary arterial
hypertension classified as WHO functional class III, to improve exercise
capacity.
Dosage: 100mg once daily.
Contraindications: Mild to severe hepatic impairment;
elevated aminotransferases prior to intiation of treatment; concomitant
administration with ciclosporin
A; lactation.
Precautions: Alternative therapies should be considered
if clinical deterioration occurs despite at least 12 weeks’ treatment; an additional 12 weeks’ treatment
may be considered. Caution is recommended with co-administration of Thelin
with other treatments for pulmonary arterial hypertension. If signs of
pulmonary oedema occur with Thelin treatment, the possibility of associated
pulmonary veno-occlusive disease should be considered. Liver aminotransferase
levels must be measured prior to treatment initiation and subsequently
at monthly intervals. Thelin has been associated with dose-related decreases
in haemoglobin; haemoglobin concentrations should be checked before beginning
treatment, after one month, after three months and every three months
thereafter. Thelin increases the plasma levels of vitamin K antagonists
such as warfarin. In vitro data indicate that sitaxentan sodium
inhibits CYP2C9 and, to a lesser extent, CYP2C19, CYP3A4/5 and CYP2C8;
plasma
concentrations of drugs metabolised primarily by these isoenzymes, particularly
CYP2C9, may increase during co-administration with Thelin.
Side effects: Very common (>=1/10) headache. Common
(>=1/100, <1/10)
peripheral oedema, insomnia, dizziness, nasal congestion, epistaxis,
nausea, constipation, upper abdominal pain, vomiting, dyspepsia, diarrhoea,
flushing, muscle cramp, fatigue, increased INR, prolonged prothrombin
time.
Legal category: POM.
Net price: 28, £1,540.
Contact details: Encysive (UK) Ltd, Regus House, Highbridge,
Oxford Road, Uxbridge UB8 1HR (tel 0800 0121241).
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