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Sildenafil (Generic Viagra) 2026: Cost, Dosing, Side Effects, and How to Get It
Last updated: May 20, 2026 · Medically reviewed by Dr. Marcus Tan, MD · ~9 min read
Key Takeaways
- Active ingredient: sildenafil citrate — a PDE5 inhibitor originally developed by Pfizer as Viagra.
- FDA approval: March 27, 1998 (Viagra). Generic sildenafil approved December 2017 after Pfizer’s US patent expired.
- Cost range May 2026: as low as $0.30/pill at Cost Plus Drugs (100mg generic), $2–$5/dose through telehealth, $70–$90/dose for branded Viagra.
- Onset: 30–60 minutes; peak at ~60 minutes; effective window ~4 hours.
- Dosing: 25mg, 50mg, or 100mg as needed, up to once per day, taken 30–60 minutes before sex.
- Hard contraindication: nitrates (nitroglycerin, isosorbide) — combination can cause life-threatening hypotension.
Sildenafil is the generic version of Viagra and the most-prescribed PDE5 inhibitor for erectile dysfunction in 2026. The FDA approved branded Viagra on March 27, 1998 and generic sildenafil in December 2017. Today, generic 100mg sildenafil costs as little as $0.30 per pill at Cost Plus Drugs, $2–$5 per dose through telehealth, or $70–$90 per dose for branded Viagra. Onset is 30–60 minutes, and the effect lasts about four hours. Never combine with nitrates.
What Sildenafil Is and How It Works
Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor. During sexual stimulation, the body releases nitric oxide in the penis, which raises cGMP levels and relaxes smooth muscle in the corpus cavernosum, allowing blood inflow and an erection. PDE5 breaks down cGMP and ends the erection. Sildenafil blocks PDE5, prolonging cGMP activity and supporting an erection — but only with sexual stimulation. It does not cause spontaneous erections.
Sildenafil and tadalafil (Cialis) are the two most-prescribed PDE5 inhibitors in the US. Sildenafil has a faster onset and shorter half-life (~4 hours), while tadalafil has a slower onset and a 36-hour window. For a side-by-side breakdown see our sildenafil vs tadalafil 2026 guide. For the broader category overview, see our erectile dysfunction hub.
FDA Approval and Indications
Viagra (sildenafil citrate) received FDA approval on March 27, 1998 for the treatment of erectile dysfunction in adult men. It was the first oral medication approved for ED. A separate formulation, Revatio, was approved in June 2005 for pulmonary arterial hypertension (PAH). Pfizer’s US patent on Viagra expired in December 2017, and Teva launched the first authorized generic on December 11, 2017. Generic sildenafil from multiple manufacturers (Teva, Greenstone, Aurobindo, and others) has been available ever since at deep discounts to the branded price.
Pricing in May 2026
| Channel | Form | Cost per dose | Notes |
|---|---|---|---|
| Cost Plus Drugs | 100mg generic tablet | ~$0.30 | Cheapest US cash price; valid Rx required |
| GoodRx coupon (retail) | 100mg generic | $0.80–$3 | Varies by pharmacy; tablets often split |
| Ro | Generic sildenafil | ~$2/dose | Bundled with telehealth visit; no insurance needed |
| Hims | Generic sildenafil | ~$2–$5/dose | Subscription pricing; chewable Hard Mints option |
| Branded Viagra (Pfizer) | 100mg tablet | $70–$90/dose | Cash retail; insurance copay varies |
| Authorized generic (Pfizer) | 100mg tablet | ~$30–$40/dose | Same molecule as branded, half-price retail |
| Insurance copay | Generic | $0–$15/month | Many commercial plans cover; most exclude branded |
Prices verified May 2026. Subject to change — check pharmacy and provider sites for current pricing. Many patients legitimately split a single 100mg pill into halves or quarters to reach 25mg or 50mg doses, further lowering per-dose cost.
For the full landscape of online prescribers, see our best online Viagra prescription 2026 guide.
Dosing
| Dose | When to take | Notes |
|---|---|---|
| 25mg | 30–60 minutes before sex | Starting dose for older patients or moderate hepatic/renal impairment |
| 50mg (typical start) | 30–60 minutes before sex | Standard starting dose for most adults |
| 100mg (max) | 30–60 minutes before sex | Titrate up only if 50mg insufficient and tolerated |
Maximum dosing frequency is once per 24 hours. Effect is reduced by a heavy or high-fat meal — take on an empty stomach or after a light meal for best onset. Sildenafil requires sexual stimulation to produce an erection; it is not an aphrodisiac.
Side Effects and Warnings
Most common (occurring in >2% of patients in clinical trials):
- Headache (16%)
- Flushing (10%)
- Dyspepsia / indigestion (7%)
- Nasal congestion (4%)
- Visual disturbance — blue-tinted vision, light sensitivity (3%)
- Back pain, myalgia, dizziness
Rare but serious:
- Priapism (erection lasting >4 hours) — medical emergency, seek ER care immediately
- Sudden vision loss (non-arteritic anterior ischemic optic neuropathy, NAION) — stop drug and seek care
- Sudden hearing loss — rare but reported, often with tinnitus
- Severe hypotension — especially when combined with nitrates or alpha blockers
- Cardiovascular events in patients with unstable cardiac disease engaging in sexual activity
Absolute contraindications
- Nitrates in any form (nitroglycerin tablets/sprays, isosorbide mononitrate or dinitrate, recreational “poppers” / amyl nitrite) — potentially fatal hypotension.
- Riociguat (Adempas, a guanylate cyclase stimulator) — same hypotension risk.
- Severe cardiovascular instability: recent MI (within 6 months), unstable angina, severe heart failure, life-threatening arrhythmia, severe hypotension (BP <90/50), or uncontrolled hypertension.
- Known hypersensitivity to sildenafil.
Drug interactions
- Alpha blockers (doxazosin, tamsulosin) — additive hypotension; separate dosing or lower sildenafil dose
- Strong CYP3A4 inhibitors (ritonavir, ketoconazole, itraconazole, clarithromycin) — lower starting dose to 25mg
- Grapefruit juice — mild CYP3A4 inhibition; avoid high intake
How to Get Sildenafil Online
Sildenafil requires a prescription in the US. There is no over-the-counter version. The three lowest-friction paths in 2026:
- Ro — async telehealth, generic sildenafil bundled at ~$2/dose, no insurance required. Most popular ED telehealth in 2026.
- Hims — offers generic sildenafil and the chewable “Hard Mints” sildenafil formulation; subscription pricing.
- Cost Plus Drugs + your PCP — cheapest absolute price ($0.30/pill 100mg) but requires getting an Rx through your regular provider.
Insurance coverage for generic sildenafil for ED is now common on commercial plans (typically $0–$15/month copay), though many plans still cap monthly tablet count at 4–6 doses. Medicare Part D coverage for ED-indication sildenafil remains limited; Revatio (PAH indication) is covered.
For a head-to-head against the longer-acting alternative, see our sildenafil vs tadalafil comparison.
Frequently Asked Questions
Is sildenafil the same as Viagra?
Yes. Sildenafil is the generic name for the active ingredient in Viagra (sildenafil citrate). Pfizer’s US patent expired in December 2017, and the FDA has approved generic sildenafil from multiple manufacturers since then. Generics contain the same active ingredient at the same strengths and meet FDA bioequivalence standards, so onset, peak effect, duration, and side-effect profile are equivalent to branded Viagra.
How much does sildenafil cost in 2026?
Generic sildenafil ranges from $0.30 per 100mg pill at Cost Plus Drugs to $2–$5 per dose through telehealth services like Ro and Hims, $30–$40 for Pfizer’s authorized generic, and $70–$90 for branded Viagra. Insurance copays for the generic are typically $0–$15/month on commercial plans, with most plans capping monthly tablet count at 4–6 doses.
How long does sildenafil take to work?
Sildenafil typically begins working in 30–60 minutes, with peak plasma concentration around 60 minutes after dosing on an empty stomach. The therapeutic window lasts about 4 hours, with the strongest effect in the first 2 hours. A heavy or high-fat meal can delay onset by 30–60 minutes and reduce peak concentration. Sexual stimulation is required — sildenafil does not produce a spontaneous erection.
How long does sildenafil last?
The effective window is approximately 4 hours from onset. The drug’s half-life is about 4 hours, so most clinically meaningful effect is gone within 5–6 hours of dosing. If you need a longer window (up to 36 hours), tadalafil (Cialis) is the typical alternative. Maximum dosing frequency for sildenafil is once per 24 hours regardless of dose.
What dose of sildenafil should I start with?
50mg is the standard starting dose for most adult men. Patients over 65, or with mild-to-moderate kidney or liver impairment, or taking strong CYP3A4 inhibitors (ritonavir, ketoconazole, clarithromycin) should start at 25mg. The maximum approved dose is 100mg once per 24 hours. Titration up to 100mg is appropriate only if 50mg is insufficient and well tolerated.
Can I take sildenafil every day?
Sildenafil is approved for on-demand use, not daily dosing. Maximum frequency is once per 24 hours. For patients who prefer a daily-use PDE5 inhibitor that supports spontaneous sexual activity over a long window, daily-dose tadalafil 2.5mg or 5mg is the FDA-approved option. Talk to your prescriber about which dosing pattern fits your sexual frequency and side-effect tolerance.
What should I never combine with sildenafil?
Never combine sildenafil with nitrates in any form — nitroglycerin tablets or sprays, isosorbide mononitrate or dinitrate, or recreational amyl nitrite (“poppers”). The combination can cause life-threatening hypotension. Riociguat (Adempas) is also absolutely contraindicated. Use caution with alpha blockers for BPH (doxazosin, tamsulosin), strong CYP3A4 inhibitors, and avoid grapefruit juice in large amounts.
What are the most common sildenafil side effects?
Headache (16%), facial flushing (10%), indigestion (7%), nasal congestion (4%), and transient blue-tinted vision or light sensitivity (3%) are the most common. Back pain, muscle aches, and dizziness occur less often. Rare but serious effects include priapism (erection >4 hours, a medical emergency), sudden vision loss (NAION), and sudden hearing loss. Stop the drug and seek emergency care if these occur.
Sources
- FDA Viagra (sildenafil) prescribing information (verified May 2026)
- FDA generic Viagra approval announcement (Dec 2017)
- Cost Plus Drugs sildenafil pricing (verified May 2026)
- American Urological Association ED guideline
- Goldstein et al., NEJM 1998 — original sildenafil RCT
Medical disclaimer: Information here is educational only. Sildenafil can cause serious side effects including priapism, sudden vision loss, and life-threatening hypotension when combined with nitrates. Do not take sildenafil without a valid prescription from a licensed clinician who has reviewed your medical history and current medications.