Erectile dysfunction (ED) affects roughly 30 million American men, and four brand-name PDE5 inhibitors dominate US prescriptions: Viagra (sildenafil), Cialis (tadalafil), Levitra (vardenafil) and Stendra (avanafil). All four are effective — but they differ meaningfully in onset speed, how long they last, food and alcohol interactions, side-effect profile, and (most importantly for US patients) out-of-pocket cost. This guide breaks down which one wins for which situation, with 2026 US pricing and how to save the most with FDA-approved generics.
Reviewed against clinical guidance from the American Urological Association (AUA) and cross-checked with pricing data from GoodRx and the U.S. Food and Drug Administration.
How PDE5 inhibitors work
All four medications belong to the same drug class: phosphodiesterase type 5 (PDE5) inhibitors. They block the PDE5 enzyme, which lets nitric-oxide-driven cyclic GMP accumulate in the smooth muscle of the penis. The result: relaxed vascular tissue, improved blood flow, and — with sexual stimulation — a firmer, more sustained erection. None of them create arousal on their own; they enable the physiological response when arousal is present.
Head-to-head snapshot
| Medication | Onset | Duration | Food effect | Typical US retail (brand) | Generic cash price* |
|---|---|---|---|---|---|
| Viagra (sildenafil 50/100mg) | 30–60 min | 4–6 hr | Yes — fatty meals delay onset | $80–$100 / tablet | $2–$15 / tablet |
| Cialis (tadalafil 10/20mg) | 30–45 min | Up to 36 hr | No | $70–$90 / tablet | $1–$10 / tablet |
| Levitra (vardenafil 10/20mg) | 30 min | 4–5 hr | Mild — high-fat meals delay | Brand discontinued in US | $10–$30 / tablet |
| Stendra (avanafil 100/200mg) | 15–30 min (fastest) | 6 hr | Minimal | $90–$130 / tablet | Not yet available as generic |
*Cash-pay ranges reflect typical 2026 US retail pharmacy pricing with a GoodRx-style discount card at chain pharmacies. Actual price varies by pharmacy, ZIP code, quantity, and dosage.
Viagra (sildenafil): the original — best for on-demand use
Approved by the FDA in 1998, sildenafil is the most-recognized ED medication in the United States. It has the largest body of clinical evidence and works well for the majority of men.
- Best for: Planned intimacy, cost-sensitive patients, men who don't want a long "tail" of drug in the system.
- Watch out for: Fatty meals (a heavy steak dinner can push onset past 90 minutes), bluish tint to vision at higher doses.
- US cost angle: Brand Viagra runs ~$80–$100 per tablet at CVS/Walgreens/Rite Aid retail. FDA-approved generic sildenafil (available since December 2017) drops that to $2–$15 per tablet with a discount card — a 90%+ savings.
Cialis (tadalafil): the weekend pill — best for spontaneity
Tadalafil's defining feature is its 36-hour half-life window, which is why it earned the nickname "the weekend pill." Take it Friday evening; it's still active Sunday morning.
- Best for: Men who want spontaneity, couples with irregular sexual schedules, and men who also have benign prostatic hyperplasia (BPH) — tadalafil is FDA-approved to treat both conditions in a single 5mg daily tablet.
- Watch out for: Back and leg muscle aches (PDE11 cross-reactivity), which are more common than with sildenafil.
- US cost angle: Generic tadalafil launched in 2018 and is now the cheapest branded-equivalent PDE5 in America, often under $1 per tablet at 90-day supply pricing.
Levitra (vardenafil): a niche middle option
Vardenafil is pharmacologically close to sildenafil but slightly more potent milligram-for-milligram. The brand Levitra was discontinued in the US market, but generic vardenafil is widely available and remains a solid third-line option — particularly for men who don't respond well to sildenafil.
- Best for: Men who experienced side effects on sildenafil or Cialis; diabetic men (some evidence of slightly better response).
- Watch out for: Similar side-effect profile to sildenafil; QT prolongation risk means caution with certain heart-rhythm medications.
Stendra (avanafil): the fastest onset — best for time-sensitive dosing
Approved by the FDA in 2012, avanafil is the newest of the four and has the fastest onset — as quick as 15 minutes. It's also the most receptor-selective, which translates to fewer visual side effects and less nasal congestion.
- Best for: Men who want the fastest possible onset, or who experienced vision changes with Viagra.
- Watch out for: Cost — Stendra has no US generic yet, so out-of-pocket pricing runs $90–$130 per tablet. Insurance coverage is spottier than the other three.
Side effects — what to actually expect
All four share the same class-level side effects, most of which are mild and dose-dependent:
- Headache (most common — 10–15% of users)
- Facial flushing
- Nasal congestion
- Indigestion / heartburn
- Muscle aches (mainly Cialis)
- Bluish tint to vision (mainly Viagra)
Rare but serious side effects — priapism (erection lasting more than 4 hours), sudden hearing loss, or sudden vision loss — require immediate emergency care. All four are absolutely contraindicated with nitrate medications (nitroglycerin, isosorbide) due to fatal hypotension risk.
Heart safety in the US context
PDE5 inhibitors are generally cardiovascular-safe for men who can tolerate moderate physical activity. However, per American Heart Association guidance, men with recent myocardial infarction (within 90 days), unstable angina, uncontrolled hypertension, or those on nitrates should not use these medications. ED is also an independent predictor of future cardiovascular disease — talk to your primary-care physician, not just an online prescriber.
How to save the most in the USA
ED medications are almost never covered by commercial insurance or Medicare Part D unless there's a medically documented reason (post-prostatectomy, spinal injury). That leaves most American men paying cash. Here's how to bring the number down:
- Switch to the generic. Generic sildenafil and tadalafil are FDA-approved bioequivalents and deliver identical clinical results at 5–10% of the brand price.
- Use a discount card. Free tools like GoodRx, SingleCare, and Amazon Pharmacy Discount often beat the pharmacy's cash price by 60–80%.
- Split higher-dose tablets. A 100mg sildenafil tablet is often the same price as a 50mg tablet; a pill splitter cuts the effective per-dose price in half. Ask your prescriber first.
- Buy 90-day supplies. Volume pricing at mail-order and warehouse pharmacies (Costco, Amazon Pharmacy) drops per-tablet costs substantially.
- Wholesale sourcing for clinics. US telehealth clinics, men's health practices, and longevity centers can source certified generic sildenafil, tadalafil, and vardenafil at wholesale tier-one pricing through MY US HEALTHCARE — see our Wholesale Buying Guide for the workflow.
Which one is "best"? Our verdict
- Best overall value: Generic tadalafil (Cialis) — cheapest, longest-acting, treats BPH too.
- Best for planned use / cost-sensitive: Generic sildenafil (Viagra).
- Best for fastest onset: Stendra (avanafil) — if you can absorb the cost.
- Best backup if others don't work: Generic vardenafil (Levitra).
Frequently asked questions
Are generic sildenafil and tadalafil as effective as brand Viagra and Cialis?
Yes. The FDA requires generics to demonstrate bioequivalence — the same active ingredient, same dose, same absorption profile within a narrow statistical tolerance. Clinical outcomes are indistinguishable.
Can I buy Viagra or Cialis over the counter in the US?
No. All four PDE5 inhibitors require a valid US prescription. Products sold as "herbal Viagra" or "OTC ED pills" at gas stations and vitamin shops have been repeatedly flagged by the FDA for containing undisclosed active pharmaceutical ingredients — avoid them.
Can I combine ED medications with alcohol?
One or two drinks is usually fine. Heavy drinking blunts the effect of all four and increases the risk of orthostatic hypotension (dizziness on standing).
How long before Viagra/Cialis actually work?
Plan for 30–60 minutes after taking Viagra or Cialis, 15–30 minutes for Stendra, and 30 minutes for Levitra. Take on a light-to-moderate meal, not immediately after a heavy fatty dinner.
Related guides on MY US HEALTHCARE
- ED Causes & Treatment Guide
- Sildenafil vs Tadalafil — Deep Dive
- Wholesale Generic Medications: A Buying Guide
This article is for informational and educational purposes only and is not a substitute for medical advice from a licensed physician. Always consult a US-licensed healthcare provider before starting, stopping, or changing any medication. MY US HEALTHCARE serves US clinics, telehealth prescribers, and wellness centers with wholesale generic medication sourcing — contact our team for tiered clinic pricing.