Last reviewed 2026-04-23 · How we verify

Mono-Therapy with Sildenafil

Sildenafil inhibits phosphodiesterase-5 (PD-5) to increase cyclic GMP levels, promoting vasodilation and improving blood flow.

Sildenafil inhibits phosphodiesterase-5 (PD-5) to increase cyclic GMP levels, promoting vasodilation and improving blood flow. Used for Pulmonary arterial hypertension (PAH).

At a glance

Mechanism of action

Sildenafil blocks the enzyme phosphodiesterase-5, which normally breaks down cyclic guanosine monophosphate (cGMP). By preventing cGMP degradation, sildenafil allows sustained vasodilation in vascular smooth muscle. This mechanism improves blood flow and reduces vascular resistance, with applications across multiple therapeutic areas including pulmonary hypertension and erectile dysfunction.

Approved indications

• Pulmonary arterial hypertension (PAH)

Common side effects

• Headache
• Flushing
• Dyspepsia
• Nasal congestion
• Hypotension
• Visual disturbances

Key clinical trials

• Mono vs. Dual Therapy for Pediatric Pulmonary Arterial Hypertension (PHASE3)
• Sildenafil Added Effect in Dapoxetine Non-responding Mono-symptomatic Premature Ejaculation (PE) (PHASE2)
• Sidlenafil in Combination With Oral Anticoagulants in Patients With Intermediate-high Risk of Pulmonary Embolism (PHASE1)
• Sildenafil for Chronic Obstructive Pulmonary Disease (COPD) Associated Pulmonary Hypertension (PHASE4)

Primary sources

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Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Mono-Therapy with Sildenafil CI brief — competitive landscape report
• Mono-Therapy with Sildenafil updates RSS · CI watch RSS
• Johns Hopkins University portfolio CI