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PDE5 Inhibitor — Pulmonary Arterial Hypertension

Sildenafil

Brand names: Revatio (PAH), Viagra (erectile dysfunction — different indication)

This entry covers sildenafil as a phosphodiesterase type-5 inhibitor used to treat pulmonary arterial hypertension, distinct from its erectile-dysfunction indication. It is taken orally, typically three times daily, under specialist supervision.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It inhibits phosphodiesterase type-5 in pulmonary vascular smooth muscle, increasing cyclic GMP and producing pulmonary vasodilation.

Prescribing in practice

  • It must never be combined with nitrates or with the guanylate cyclase stimulator riociguat because of the risk of profound hypotension.
  • Use caution in patients prone to hypotension and review interacting drugs such as strong CYP3A4 inhibitors and alpha-blockers.
  • Counsel on common vasodilatory effects including headache, flushing and visual disturbance.

Monitoring

Monitor blood pressure, symptom control and for visual or hearing changes during treatment.

Counselling the patient

  • Never take nitrates with this medicine and tell other prescribers you use it for your lungs.
  • Headache, flushing or a blue tinge to vision can occur; report sudden vision or hearing loss.
  • Take it regularly as prescribed for your pulmonary hypertension.

Evidence & guidelines

NICE and the SPC support sildenafil as a phosphodiesterase type-5 inhibitor for pulmonary arterial hypertension.

Reference: SUPER-1 Trial (Galiè et al. NEJM 2005); AMBITION Trial (Galiè et al. NEJM 2015); ESC/ERS PAH Guidelines 2022; SPC Revatio; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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