Dual Endothelin Receptor Antagonist (ERA) Pregnancy: Contraindicated in pregnancy (animal reproductive toxicity/teratogenicity; human data lacking). Women of child-bearing potential must use reliable contraception and have monthly pregnancy tests. Breast-feeding not recommended.

Bosentan

Brand names: Tracleer

Bosentan is a dual endothelin receptor antagonist used in the treatment of pulmonary arterial hypertension and to reduce new digital ulcers in systemic sclerosis.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 62.5 mg twice daily for 4 weeks, then increased to maintenance 125 mg twice daily

Route: Oral

Frequency: twice daily (morning and evening)

Pulmonary arterial hypertension: initiate 62.5 mg twice daily for 4 weeks then increase to maintenance 125 mg twice daily. Same regimen applies to systemic sclerosis with ongoing digital ulcer disease. Treatment to be initiated and monitored by a physician experienced in PAH/systemic sclerosis. In case of clinical deterioration despite 125 mg twice daily, some patients may slightly improve when the dose is increased to 250 mg twice daily (liver toxicity is dose-dependent — careful benefit/risk assessment). Discontinuation: consider gradual dose reduction (halving the dose for 3 to 7 days). Liver aminotransferases must be measured before initiation, monthly during treatment, and 2 weeks after any dose increase. Should only be initiated if systemic systolic blood pressure is >85 mmHg.

Paediatric dose

Dose: 2 mg/kg

Route: Oral

Frequency: twice daily (morning and evening)

Max: 2 mg/kg twice daily — no additional benefit from higher doses or from three-times-daily dosing

Children with PAH aged 1 year and older: recommended starting and maintenance dose 2 mg/kg morning and evening. Neonates with persistent pulmonary hypertension of the newborn (PPHN): benefit not shown, no posology recommendation can be made. No safety/efficacy data under 18 years in systemic sclerosis digital ulcer disease. Verify against a children's formulary.

Dose adjustments

Renal

No dose adjustment required in renal impairment or in patients undergoing dialysis.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

Patient weight (kg)

Verify in a children's formulary

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Moderate to severe hepatic impairment (Child-Pugh class B or C)
Baseline liver aminotransferases (AST and/or ALT) greater than 3 times the upper limit of normal
Concomitant use of ciclosporin A
Pregnancy
Women of child-bearing potential not using reliable methods of contraception

Side effects

Oedema / fluid retention (very common, ~13.2%)
Headache (very common, ~11.5%)
Abnormal liver function test (very common, ~10.9%)
Anaemia / haemoglobin decrease (common, ~9.9%)
Hypersensitivity reactions including dermatitis, pruritus and rash (common)

Interactions

Ciclosporin A — concomitant use contraindicated
Hormonal contraceptives (oral, injectable, transdermal, implantable) — may be rendered ineffective; must not be used as sole method of contraception
Inhibitors of the bile salt export pump (e.g. rifampicin, glibenclamide, ciclosporin A) — may increase risk of liver dysfunction

Clinical monograph

How it works

It antagonises endothelin-1 at both ETA and ETB receptors, reducing endothelin-mediated pulmonary vasoconstriction and vascular proliferation.

Prescribing in practice

It is hepatotoxic and teratogenic; liver enzymes must be monitored and effective contraception is required, with reliable pregnancy testing before and during treatment.
It reduces the efficacy of hormonal contraceptives, so hormonal methods alone must not be relied upon for contraception.
It is a CYP inducer with numerous interactions, including with ciclosporin and glibenclamide, which are contraindicated.

Monitoring

Monitor liver transaminases regularly throughout treatment, along with haemoglobin and pregnancy status in those who can become pregnant.

Counselling the patient

Use reliable non-hormonal or additional contraception and avoid pregnancy while taking this medicine.
Attend for regular liver blood tests and report nausea, vomiting, abdominal pain or yellowing of the skin or eyes.

Evidence & guidelines

Bosentan's efficacy in pulmonary arterial hypertension was established in the BREATHE trials, and it is recommended in specialist guidance.

Reference: RAPIDS-2 Trial (Matucci-Cerinic et al, Ann Rheum Dis 2008); NICE TA233; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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