Sildenafil [Active Ingredient]

Sildenafil is a well-known active pharmaceutical ingredient used primarily to treat erectile dysfunction (ED). It works by relaxing the smooth muscle of blood vessels and improving blood flow. Sildenafil may also be prescribed for pulmonary arterial hypertension (PAH).

This page contains essential medical information, usage guidelines, safety instructions, and a list of medicines that contain Sildenafil.

Information about Sildenafil

Sildenafil Uses

Sildenafil is commonly used for:

Treatment of erectile dysfunction (ED),
Improvement of erectile function in men of different age groups,
Treatment of pulmonary arterial hypertension (PAH),
Sometimes used in benign prostatic hyperplasia (BPH) therapy

Sildenafil helps by enhancing blood flow to specific tissues through vasodilation.

How Sildenafil works

Sildenafil is a PDE-5 (phosphodiesterase-5) inhibitor.

It works by blocking the PDE-5 enzyme, leading to increased levels of cyclic GMP (cGMP).

As a result, the blood vessels in certain parts of the body—including the penis—relax and widen, improving blood flow during sexual stimulation.

This helps achieve and maintain an erection suitable for intercourse.

Common side effects of Sildenafil

Most side effects are mild and temporary.

Common reactions include:

Headache,
Nasal congestion,
Flushing,
Dizziness,
Vision changes,
Indigestion,
Nausea,
Shortness of breath

If side effects persist or worsen, medical attention is recommended.

CONTENT DETAILS

Written By

Douglas C. Goldberg, MD

Board Certified in Internal Medicine

Reviewed By

Philip Schein, MD

Medical Reviewer, Clinical Pharmacology

Last updated

27 Nov 2025 | 05:47 AM (UTC)

Medicine brands for Sildenafil

Eriacta
Dosage: 100mg
from $50.007 variant(s)
Viagra
Dosage: 25mg, 50mg, 100mg
from $39.8926 variant(s)
Female Viagra
Dosage: 100mg
from $36.009 variant(s)
Nizagara
Dosage: 25mg, 50mg, 100mg
from $42.0020 variant(s)
Lady Era
Dosage: 50mg, 100mg
from $41.0013 variant(s)
Zenegra
Dosage: 100mg
from $41.007 variant(s)
Caverta
Dosage: 50mg, 100mg
from $108.003 variant(s)
Penegra
Dosage: 25mg, 50mg, 100mg
from $35.0025 variant(s)
Vimax
Dosage: 50-mg, 100-mg
from $10.0010 variant(s)
Sildigra Gold
Dosage: 200-mg
from $23.003 variant(s)
Kamagra
Dosage: 50mg, 100mg
from $32.0018 variant(s)
Cenforce Soft
Dosage: 100mg
from $36.008 variant(s)
Sildigra
Dosage: 25mg, 50mg, 100mg, 120mg
from $33.0024 variant(s)
Womenra
Dosage: 100mg
from $40.009 variant(s)
Silagra
Dosage: 100mg
from $40.006 variant(s)
Viagra Jelly
Dosage: 100mg
from $74.004 variant(s)
P-Force Plus
Dosage: 130-mg
from $26.003 variant(s)
Viagra Capsules
Dosage: 100mg
from $40.009 variant(s)
Viprogra
Dosage: 100-mg
from $29.005 variant(s)
Viagra Soft Flavoured
Dosage: 100mg
from $66.006 variant(s)

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Expert advice for Sildenafil

Take Sildenafil 30 minutes to 4 hours before sexual activity.
Do not take more than once per day.
Avoid using Sildenafil if you are taking nitrates (medications for chest pain).
Avoid alcohol, which may reduce the medicine’s effectiveness.
Contact a doctor if an erection lasts more than 4 hours.
Do not use Sildenafil if you recently had a heart attack (past 3 months) or stroke (past 6 months).
People with diabetes or high blood pressure can use Sildenafil safely when prescribed.

Frequently Asked Questions

How long does Sildenafil take to work?

Most men feel the effect within 30–60 minutes after taking the medication.

Can I get Sildenafil without a prescription?

A valid prescription is required in most countries. Online consultation may be available.

Can I take Sildenafil more than once a day?

No. The recommended frequency is once per 24 hours.

Can I take Sildenafil with alcohol?

Alcohol may reduce its effectiveness and increase the risk of dizziness.

Does Sildenafil help with premature ejaculation?

Not directly. It helps maintain erection but does not delay ejaculation.