ED TREATMENT – Medically Reviewed:

Viagra 2026: Prices, Prescriptions & Delivery Options

Michael Chen

Board Certified Urology – Harvard – 18+ Years

Reviewed by our Medical Review Board

Patient Support: (212) 555-0147

Prescription Required 4-6 Hours Duration Take 30-60 Min Before Not for Heart Patients (Nitrates)

Viagra (Sildenafil) is a PDE5 inhibitor used to treat erectile dysfunction and pulmonary arterial hypertension. The first FDA-approved oral treatment for ED, it works quickly and reliably for most men. However, it requires medical screening for heart conditions and drug interactions.

This medically reviewed guide covers everything patients need to know: how Sildenafil works, proper dosing, critical safety protocols, side effects, and warnings. Whether you are starting treatment or managing long-term therapy, understanding these fundamentals is essential for safe use.

Never Combine with Nitrates

Taking Viagra with nitrates (nitroglycerin, isosorbide) can cause a fatal drop in blood pressure. Always inform your doctor of all medications before starting Viagra.

View Safety Information

What Is Viagra and How It Works

Viagra (Sildenafil) is a PDE5 inhibitor. FDA-approved since 1998 for erectile dysfunction and since 2005 for pulmonary arterial hypertension (as Revatio).

Unlike Cialis (36 hours), Viagra works for 4-6 hours and must be taken 30-60 minutes before sexual activity. It requires sexual stimulation to work – it does not cause automatic erections. It also relaxes blood vessels in the lungs, improving exercise capacity in PAH patients.

Why Viagra Requires Medical Oversight

Unlike over-the-counter medications, Viagra requires:

  • Medical screening for heart conditions and blood pressure
  • Review of all medications (especially nitrates and alpha-blockers)
  • Evaluation of liver and kidney function
  • Discussion of sexual activity safety for cardiac patients

Conditions Treated with Viagra

Erectile Dysfunction

  • ED (as-needed dosing)
  • Performance anxiety
  • Post-prostatectomy ED
  • Diabetes-related ED

Pulmonary

  • Pulmonary arterial hypertension (Revatio)
  • High-altitude pulmonary edema (off-label)
  • Raynaud’s phenomenon (off-label)
  • Scleroderma-related PAH

Not Approved For

  • Cognitive enhancement
  • Athletic performance
  • Recreational use
  • Premature ejaculation (not primary indication)

Other Uses

  • Antidepressant-induced sexual dysfunction
  • High-altitude sickness prevention
  • Peyronie’s disease (adjunct)
  • Female sexual arousal disorder (off-label)

Dosage Guidelines

CRITICAL: Dosage must be determined by your physician. Never self-adjust or share medication.

Condition / Use Typical Dose Frequency Duration
ED (standard) 50mg Before activity 4-6 hours
ED (low dose) 25mg Before activity 4-6 hours
ED (high dose) 100mg Before activity 4-6 hours
PAH (Revatio) 20mg 3x daily Long-term

*These are general guidelines only. Your physician will determine exact dosing based on your individual medical profile.

Safety & Warnings

Cardiovascular Emergency Warning

If you experience chest pain, dizziness, or nausea during sexual activity after taking Viagra, stop immediately and seek emergency care. This may indicate a serious heart problem.

  • Chest pain or pressure during sexual activity
  • Dizziness, lightheadedness, or fainting
  • Nausea or vomiting with exertion
  • Pain radiating to jaw, arm, or back

Sexual activity can strain the heart. Cardiac clearance is required for patients with heart disease.

Side Effects

Common Side Effects

  • Headache (16% of patients) – usually mild
  • Facial flushing (10%) – temporary warmth and redness
  • Indigestion (7%) – take with light meal
  • Nasal congestion (4%) – decongestant may help
  • Visual changes (blue tint, sensitivity to light) – rare, temporary

Serious Side Effects – Seek Medical Attention

  • Sudden vision loss (NAION) – seek immediate care
  • Sudden hearing loss or ringing in ears
  • Priapism (erection lasting >4 hours) – emergency
  • Severe allergic reaction (swelling, difficulty breathing)
  • Chest pain or irregular heartbeat during activity

Who Cannot Take Viagra?

Absolute Contraindications

  • Use of nitrates (nitroglycerin, isosorbide) – fatal blood pressure drop
  • Use of recreational drugs (“poppers” – amyl nitrite)
  • Severe heart disease or recent heart attack/stroke
  • Hypersensitivity to sildenafil

Use With Extreme Caution

  • Alpha-blockers (doxazosin, tamsulosin) – may cause hypotension
  • Blood pressure medications – additive hypotensive effect
  • Liver or kidney disease – dose adjustment required
  • Retinitis pigmentosa or severe vision loss history
  • Bleeding disorders or stomach ulcers
  • Deformed penis (Peyronie’s, cavernosal fibrosis)

Frequently Asked Questions

Can I buy Viagra online without a prescription?
No. Viagra is prescription-only in the US. Websites offering “no RX Viagra” sell illegal, potentially counterfeit products. Counterfeit Viagra has been found to contain dangerous substances including paint, printer ink, amphetamines, and unlisted drugs.
How fast does Viagra work?
Onset: 30-60 minutes
Peak effect: 1 hour
Duration: 4-6 hours

Take on an empty stomach or with a light meal for fastest absorption. Heavy or fatty meals can delay onset by 1-2 hours.
What if I miss a dose?
Viagra is taken as-needed before sexual activity – there is no daily schedule. Take 30-60 minutes before intimacy. Do not take more than one dose per day.
Can I drink alcohol while taking Viagra?
Moderate alcohol (1-2 drinks) is generally safe. However, excessive alcohol can reduce effectiveness and increase side effects (dizziness, headache). Heavy drinking also causes ED independently. Avoid grapefruit juice – it increases sildenafil levels.
Is Viagra better than Cialis?
Different, not necessarily better. Viagra works faster (30 min vs 45 min) and costs less. Cialis lasts 36 hours vs Viagra’s 4-6 hours and offers daily dosing. Choice depends on lifestyle, medical history, and personal preference. Both require prescriptions and have the same contraindications.

Sources & References

  1. U.S. Food and Drug Administration. Viagra (Sildenafil) Prescribing Information. Revised 2022. fda.gov
  2. MedlinePlus. Sildenafil. U.S. National Library of Medicine. medlineplus.gov
  3. American Urological Association. ED Treatment Guidelines. auanet.org
  4. National Institutes of Health. PAH Treatment Guidelines. nhlbi.nih.gov

Need Help With Your ED Treatment?

Our patient support team can explain dosing options, answer questions about side effects, and connect you with a licensed urologist for personalized care.

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Prescription requires medical consultation and cardiac screening. Not for patients taking nitrates. Available at 35,000+ pharmacies nationwide.

Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Viagra is a prescription medication for erectile dysfunction and pulmonary arterial hypertension. Never start, stop, or change your dose without consulting a qualified healthcare provider. Sexual activity may strain the heart – cardiac clearance is required for patients with cardiovascular conditions.

Editorial Standards: Content is medically reviewed by Michael Chen, MD, a board-certified Urology. Last medically reviewed and updated on May 12, 2026. We regularly update this page to reflect the latest FDA guidelines and clinical research.

Emergency Notice: If you experience chest pain, dizziness, or nausea during sexual activity after taking Viagra, or an erection lasting more than 4 hours, seek emergency medical attention immediately.

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