Sildenafil Citrate

Also known as: sildenafil, Viagra (branded), Revatio (branded), PDE5 inhibitor

Sexual Well-Being

In plain English

Sildenafil is the original 'little blue pill' for erectile dysfunction. It improves blood flow to the penis when a man is sexually aroused and is usually taken about an hour before sexual activity. It is FDA-approved and taken by mouth. Like other drugs in its class, it must never be combined with nitrate heart medicines.

The science

Sildenafil is a PDE5 inhibitor that potentiates nitric-oxide/cGMP signaling in the corpus cavernosum, improving erection with sexual stimulation. The landmark NEJM trial (Goldstein 1998) established its efficacy across organic, psychogenic, and mixed erectile dysfunction, and PDE5 inhibitors are first-line in the AUA guideline. Onset is ~30-60 minutes with a ~4-hour half-life; absorption is delayed by fatty meals. Sildenafil is also FDA-approved for pulmonary arterial hypertension (as Revatio). Contraindicated with nitrates and with guanylate cyclase stimulators; caution with alpha-blockers. Common adverse effects are headache, flushing, dyspepsia, nasal congestion, and transient blue-tinged vision (PDE6 cross-reactivity); rare events include NAION and priapism. FDA-approved tablets exist; compounded SR capsules, troches, and topical arousal creams are not FDA-approved formulations.

References

• Goldstein et al., N Engl J Med 1998 (oral sildenafil for ED)
• Burnett et al., J Urol 2018 (AUA Erectile Dysfunction Guideline)