The Complete Guide

Vardenafil & Avanafil: The Complete Guide to the Other Two PDE5 Inhibitors

Two genuine alternatives to sildenafil and tadalafil, each with its own real pharmacological identity worth understanding on its own terms.

Complete Guide · ~17 min read · Last updated July 2026

Why We Cover These Two Together

Vardenafil and avanafil are the two PDE5 inhibitors in this catalog that don't have a single, dominant public identity the way sildenafil (Viagra) and tadalafil (Cialis) do. That's not a reflection of their actual effectiveness — both are legitimate, real ED medications with their own clinical trial data and, in vardenafil's case, a long FDA-approval history — it's a reflection of market timing and brand recognition. We cover them together here because they tend to come up for the same kind of reader: someone who's already tried sildenafil or tadalafil and is specifically looking for an alternative within the same drug class, rather than someone encountering PDE5 inhibitors for the first time.

It's worth being direct about why this guide exists as a combined piece rather than two separate ones, the way the sildenafil and tadalafil guides are split out individually: neither vardenafil nor avanafil has generated the volume of dedicated research, marketing history, or cultural presence that would justify treating each in the same depth as the two market leaders. That's a statement about market position and available source material, not about clinical legitimacy — both remain real, FDA-studied PDE5 inhibitors, and we'd rather tell you plainly that there's less public material to draw on for either than pad this guide with speculation to make it look otherwise.

Vardenafil: History and Development

Vardenafil was developed by Bayer, initially co-marketed in the U.S. under the brand name Levitra alongside GlaxoSmithKline and Schering-Plough, a three-company marketing arrangement that was somewhat unusual for the category. The FDA approved Levitra on August 19, 2003 — the same year as tadalafil's U.S. approval, meaning sildenafil had roughly a five-year head start on both of its major competitors, which arrived in the U.S. market within months of each other. By 2005, promotional rights had consolidated back to Bayer alone.

One genuinely interesting fact about vardenafil's history: Bayer discontinued the brand-name Levitra tablet in the U.S. in 2018, and formally notified the FDA it was doing so "for business reasons" — not safety or effectiveness. The FDA subsequently confirmed, in a series of federal determinations issued between 2019 and 2023, that Levitra's discontinuation didn't reflect any safety or effectiveness concern, which matters practically because it's what allows generic vardenafil manufacturers to keep receiving FDA approval for new generic versions referencing the original Levitra approval, even though the brand-name product itself is no longer sold. In other words, the brand disappeared from the U.S. market for business reasons while the underlying molecule, and its generic manufacturing pathway, remained fully active.

Vardenafil: How It Compares Pharmacologically

Vardenafil's pharmacokinetic profile sits closer to sildenafil's than to tadalafil's — both are as-needed medications with a several-hour duration window rather than tadalafil's much longer one, and the standard starting-dose recommendation for vardenafil (commonly 10mg, adjustable up to 20mg or down to 5mg) closely mirrors sildenafil's dosing philosophy of a moderate starting point with room to adjust. Some prescribers and patients report a subjectively different response between vardenafil and sildenafil despite the pharmacological similarity — a common reason vardenafil comes up specifically for people who've already tried sildenafil without fully satisfying results and are looking for an alternative within the same mechanism rather than jumping to a differently-structured option like tadalafil.

Avanafil: History and Development

Avanafil has the most recent origin story of the four active ingredients in this catalog, and the most international development path. It was originally discovered and developed by Mitsubishi Tanabe Pharma Corporation in Japan under the compound code TA-1790. VIVUS, Inc., a U.S. pharmaceutical company based in Mountain View, California, subsequently licensed and developed the compound for the U.S. market, ultimately bringing it through Phase III trials and FDA approval in 2012, under the brand name Stendra — nearly a decade after vardenafil and tadalafil, and 14 years after sildenafil first defined the category.

That late arrival meant avanafil entered a market where three established competitors already had decades of combined prescribing history, patient familiarity, and brand recognition. Its entire competitive positioning was built around being pharmacologically distinct in specific, describable ways — mainly speed of onset — rather than trying to out-market three already-entrenched brands on recognition alone.

Avanafil: The Fast-Onset PDE5 Inhibitor

Avanafil's defining pharmacological characteristic is speed. Clinical pharmacology data shows avanafil reaching peak plasma concentration remarkably quickly after oral dosing — commonly cited in the range of 30 to 45 minutes, among the fastest of any approved PDE5 inhibitor, with some study data showing an even faster median time to peak concentration in specific trial populations. Its half-life is comparably short too, generally cited around 5 to 6 hours, meaningfully shorter than tadalafil's much longer elimination profile and roughly in line with sildenafil's and vardenafil's. The combination of fast onset and a moderate, non-extended duration is avanafil's core pharmacological identity: engineered, in effect, for situations where a shorter window between dosing and activity — and a shorter tail afterward — is the priority.

Avanafil's absorption is affected by food in a similar direction to sildenafil's — a high-fat meal has been shown to reduce the rate of absorption and delay peak concentration by roughly an hour in clinical pharmacology studies — so the food-timing considerations that apply to sildenafil are also relevant here, even though avanafil is sometimes marketed around its rapid onset in a way that might suggest otherwise.

Strength and Dosing for Both

Both follow the same general logic that applies across this entire catalog: a moderate starting point, with adjustment based on individual response rather than defaulting to the maximum available strength on a first order. Our first-order guide covers this decision framework in more depth for anyone new to either compound.

Safety and the Nitrate Warning

Vardenafil carries an additional labeled caution around QT interval prolongation — a specific effect on the heart's electrical cycle — which is part of why its FDA labeling recommends caution with certain antiarrhythmic medications and in patients with a personal or family history of QT-related conditions specifically, a consideration that's more prominent in vardenafil's safety profile than in the other three PDE5 inhibitors in this catalog. Avanafil's FDA labeling separately notes that its interaction with amlodipine, a common blood pressure medication, meaningfully increases avanafil exposure and prolongs its half-life — a specific, documented drug interaction worth knowing about if you take a calcium channel blocker. Our full ED medication safety guide covers the complete interaction picture across the entire catalog.

Where These Sit in the Catalog

Unlike sildenafil and tadalafil, neither vardenafil nor avanafil has a single flagship tracked product with a dedicated price range in this catalog at the level of Sildatron-100 or Megalis 20. Our generic Levitra listing and the catalog's avanafil (generic Stendra) listing are both category-level entries rather than single tracked SKUs — we've deliberately not fabricated a specific flagship price for either where we don't have one confirmed, consistent with this site's policy against inventing pricing or availability. Check the current listing on HealthyRXs directly for the most up-to-date specifics on either.

Who Actually Ends Up Choosing These

In practice, vardenafil and avanafil are rarely a completely new user's first choice — sildenafil and tadalafil's dominant brand recognition means most people encountering PDE5 inhibitors for the first time gravitate toward one of those two by default. Vardenafil and avanafil tend to come up specifically for two kinds of reader: someone who's tried sildenafil or tadalafil and had a side-effect profile or subjective response they'd like to try adjusting by switching compounds within the same class, and someone who's specifically researched the pharmacokinetic differences and has a reason to want avanafil's fast-onset, shorter-tail profile or vardenafil's closer similarity to sildenafil with a different specific molecule. Neither is a "lesser" or "backup" option — both are legitimate, independently-studied PDE5 inhibitors — but neither benefits from the brand recognition that makes sildenafil and tadalafil most people's default starting point.

There's also a smaller but real category of reader who ends up here for a more mechanical reason: individual metabolic differences mean not everyone responds identically to every PDE5 inhibitor, even though they share a mechanism. A compound that produces bothersome side effects or an unsatisfying result for one person may behave differently for another, purely because of how each specific molecule is metabolized, absorbed, and cleared. That's a genuine, medically recognized reason a prescriber might suggest trying a different PDE5 inhibitor within the class rather than assuming the entire drug class simply isn't a fit — and it's a more useful lens than treating vardenafil or avanafil as a downgrade from the two more famous options.

The Broader PDE5 Inhibitor Landscape

Sildenafil, tadalafil, vardenafil, and avanafil are the four PDE5 inhibitors that have reached the U.S. market and this catalog specifically, but they're not the only ones developed globally. Other PDE5 inhibitors — udenafil, mirodenafil, lodenafil among them — have been approved and marketed in other countries, particularly South Korea, without ever reaching FDA approval or a meaningful U.S. presence. That broader context is useful mainly as a reminder that the four-compound landscape familiar in the U.S. market is a regulatory and commercial outcome, not the full universe of PDE5-inhibiting compounds that exist or have been studied — and it's part of why we're careful, in this catalog specifically, to stick to the four ingredients with real FDA history and documented pharmacology rather than expanding into less-established compounds without a comparable evidence base.

Frequently Asked Questions