ClinCalc Pro
Menu
Calculators Drugs Pathways AI Dx Donate Get the App
Pulmonary Arterial Hypertension Pregnancy: Contraindicated — Category X (Animal and human data show embryofetal toxicity; PPP mandatory with two forms of contraception)

Ambrisentan

Brand names: Volibris

Adult dose

Dose: 5 mg once daily; may increase to 10 mg once daily if tolerated
Route: Oral
Frequency: Once daily
Max: 10 mg/day
Selective endothelin ETA receptor antagonist. ARIES-1 and ARIES-2 trials demonstrated improved 6MWD. Can be combined with tadalafil (AMBITION trial — combination superior to monotherapy). Swallow whole — do not crush/split.

Paediatric dose

Route: Oral
Seek specialist opinion — not licensed in children

Dose adjustments

Renal

No dose adjustment required — unlike bosentan, no hepatic enzyme induction

Hepatic

Avoid in moderate-severe hepatic impairment (Child-Pugh B/C)

Clinical pearls

  • AMBITION trial 2015: ambrisentan + tadalafil upfront combination superior to monotherapy in treatment-naive PAH — now recommended as first-line combination therapy
  • Selective ETA antagonist: unlike bosentan (dual ETA/ETB blockade), ambrisentan preserves ETB-mediated vasodilation and pulmonary clearance of ET-1
  • Monthly LFT monitoring NOT required (unlike bosentan) — LFT at baseline and then as clinically indicated
  • Pregnancy prevention programme mandatory — two reliable methods; monthly pregnancy tests; same PPP framework as bosentan
  • Anaemia monitoring essential — Hb can fall significantly; check at 1 and 3 months then as needed

Contraindications

  • Pregnancy (Category X — teratogenic)
  • Idiopathic pulmonary fibrosis
  • Severe hepatic impairment
  • Hypersensitivity

Side effects

  • Peripheral oedema
  • Nasal congestion
  • Headache
  • Flushing
  • Anaemia — check Hb at baseline, 1 month, 3 months
  • Fluid retention

Interactions

  • Cyclosporin — increases ambrisentan levels 2x; avoid or halve dose
  • Strong CYP3A4/P-gp inhibitors
  • Hormonal contraceptives — additional contraception required

Monitoring

  • 6-minute walk distance
  • Echocardiography
  • Haemoglobin at baseline, 1 month, 3 months
  • Fluid status/oedema
  • Pregnancy tests monthly (PPP)

Reference: BNFc; BNF 90; ARIES-1/ARIES-2 Trials (Galie et al. Circulation 2008); AMBITION Trial (Galie et al. NEJM 2015); NICE TA325; SPC Volibris. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

Calculators
Drugs
Pathways