Sildenafil and vardenafil are separate active ingredients within the phosphodiesterase type 5 (PDE5) inhibitor class. They share the same broad mechanism and have notably similar fasting peak-concentration timing: both have a median Tmax of about 60 minutes in current pharmacokinetic labeling. Their terminal elimination profiles are also relatively close, at about 4 hours for sildenafil and approximately 4 to 5 hours for vardenafil.
Those similarities do not make the medicines pharmacokinetically identical. Sildenafil has a reported mean absolute oral bioavailability of about 41%, compared with approximately 15% for vardenafil. Their food-effect data, metabolite profiles, phosphodiesterase selectivity and formulation contexts also differ.
This page compares those documented properties without presenting either medicine as universally preferable. Levitra-related terminology is included within the vardenafil side of the comparison because Levitra is a brand context for vardenafil rather than a third active ingredient.
Sildenafil and vardenafil are closely related at the drug-class level. Both selectively inhibit PDE5, both are used in erectile-dysfunction product contexts and both rely on the nitric oxide-cGMP signaling pathway for their pharmacological effect during sexual stimulation.
The comparison becomes more informative when the shared mechanism is separated from compound-specific properties. Their fasting Tmax values are remarkably similar, and their terminal half-lives are within the same several-hour range, but their absolute bioavailability, food effects, metabolites and product formulations are not the same.
This makes sildenafil versus vardenafil a comparison between related PDE5 inhibitors rather than between drugs with radically different concentration-time profiles. For broader class context, see sildenafil vs other PDE5 inhibitors.
| Feature | Sildenafil | Vardenafil |
|---|---|---|
| Drug class | PDE5 inhibitor | PDE5 inhibitor |
| Primary target | PDE5 | PDE5 |
| Fasting Tmax | 30–120 minutes; median about 60 minutes | 30 minutes–2 hours; median about 60 minutes |
| Terminal half-life | About 4 hours | About 4–5 hours |
| Absolute oral bioavailability | Mean about 41% | About 15% |
| Same active ingredient? | No | No |
Both medicines act by inhibiting PDE5, the phosphodiesterase that plays an important role in degrading cGMP within erectile tissue. During sexual stimulation, nitric oxide activates guanylate cyclase and increases cGMP production. PDE5 inhibition slows cGMP degradation and allows the signaling responsible for smooth-muscle relaxation to persist.
This shared mechanism is why sildenafil and vardenafil belong to the same pharmacological class. It also means that neither medicine should be viewed as independently initiating the entire erectile-response pathway: upstream sexual stimulation and nitric oxide signaling remain relevant.
The sildenafil side of this pathway is explained in more detail on sildenafil PDE5 inhibition and the sildenafil NO-cGMP pathway.
| Mechanistic Feature | Sildenafil | Vardenafil |
|---|---|---|
| Primary enzyme target | PDE5 | PDE5 |
| NO-cGMP pathway | Central | Central |
| Reduces cGMP degradation | Yes | Yes |
| Sexual stimulation remains relevant | Yes | Yes |
| Identical molecule | No | No |
One of the most interesting features of this comparison is how similar the peak-concentration timing can appear. In fasting studies, sildenafil reaches maximum observed plasma concentrations within approximately 30 to 120 minutes, with a median Tmax of about 60 minutes. Vardenafil reaches its observed maximum between approximately 30 minutes and 2 hours, also with a median of about 60 minutes.
The similarity in Tmax does not imply identical systemic exposure. Sildenafil has a mean absolute oral bioavailability of approximately 41%, whereas vardenafil's absolute bioavailability is approximately 15%. Their distribution volumes, metabolite concentrations and complete concentration-time curves also differ.
Bioavailability percentages for two different molecules should not be interpreted as efficacy scores. They describe the fraction of administered drug reaching systemic circulation and must be understood within each compound's own potency and concentration-response relationship. For the underlying concepts, see sildenafil pharmacokinetics and sildenafil bioavailability.
| PK Parameter | Sildenafil | Vardenafil |
|---|---|---|
| Fasting Tmax range | About 30–120 minutes | About 30 minutes–2 hours |
| Median fasting Tmax | About 60 minutes | About 60 minutes |
| Absolute oral bioavailability | Mean about 41% | About 15% |
| Terminal half-life | About 4 hours | About 4–5 hours |
| Identical exposure profile? | No | No |
Because sildenafil and vardenafil both have a median fasting Tmax of approximately one hour, it is tempting to treat their onset profiles as equivalent. Tmax, however, measures the timing of peak plasma concentration rather than the first moment at which a clinically observable effect can occur.
A pharmacodynamic response can begin before maximum plasma concentration is reached. The relationship between concentration and response also depends on drug potency, tissue exposure, physiological signaling and individual sensitivity, so equal median Tmax values do not establish identical onset in every person.
This distinction is especially important on a comparison page where timing numbers can otherwise be overinterpreted. For sildenafil, see sildenafil Tmax and sildenafil onset.
| Timing Concept | What It Describes |
|---|---|
| Tmax | Time of maximum observed plasma concentration |
| Onset | Beginning of an observable pharmacodynamic effect |
| Equal median Tmax | Does not prove identical clinical onset |
| Cmax | Magnitude of the observed concentration peak |
The U.S. product-label timing frameworks for the conventional oral tablets are also broadly similar. Sildenafil ED labeling generally centers administration around approximately one hour before sexual activity while allowing a broader window extending from about 30 minutes to 4 hours beforehand.
Vardenafil film-coated tablet labeling specifies as-needed administration approximately 60 minutes before sexual activity. Sexual stimulation is required for a treatment response with vardenafil, consistent with its shared PDE5-inhibitor mechanism.
These instructions describe labeled administration timing rather than guaranteed individual onset. Similar wording around one hour should therefore not be interpreted as proof that the two medicines produce identical response curves.
| Label Timing Feature | Sildenafil | Vardenafil |
|---|---|---|
| As-needed ED framework | Yes | Yes |
| General label timing | Centered around about 1 hour before activity | Approximately 60 minutes before activity |
| Sexual stimulation relevant | Yes | Yes |
| Label timing equals guaranteed onset? | No | No |
Unlike the sildenafil-versus-tadalafil comparison, sildenafil and vardenafil do not show a large separation in terminal elimination half-life. Sildenafil and its major circulating metabolite have terminal half-lives of about 4 hours, while vardenafil and its primary circulating metabolite have terminal half-lives of approximately 4 to 5 hours.
This places both medicines within a broadly similar several-hour concentration-decline timescale. That does not mean their complete exposure curves or clinical effect durations are identical, because elimination half-life is only one part of the PK-PD relationship.
Effect duration should therefore remain separate from plasma half-life. For the sildenafil-specific distinction, see sildenafil half-life and sildenafil duration.
| Duration Concept | Sildenafil | Vardenafil |
|---|---|---|
| Terminal half-life | About 4 hours | About 4–5 hours |
| Broad elimination timescale | Several hours | Several hours |
| Half-life equals clinical duration? | No | No |
| Complete timing profiles identical? | No | No |
Food is one area where the concentration-time profiles diverge more clearly. For sildenafil tablets, a high-fat meal reduces the rate of absorption, producing an average Tmax delay of approximately 60 minutes and an average Cmax reduction of about 29 percent.
For vardenafil film-coated tablets, food-effect studies reported that high-fat meals reduced Cmax by approximately 18 to 50 percent. Current tablet labeling permits administration with or without food, but the pharmacokinetic studies still demonstrate that meal composition can alter the peak-concentration profile.
The numerical food effects should not be used as a simple ranking because the studies, formulations and measured parameters are not identical. They show instead that similar fasting Tmax values can coexist with different fed-state concentration behavior. Sildenafil-specific meal PK is covered on sildenafil food effects.
| High-Fat Meal Finding | Sildenafil | Vardenafil Film-Coated Tablet |
|---|---|---|
| Absorption profile affected? | Yes | Yes |
| Mean Tmax effect | Delayed about 60 minutes | Not summarized by the label with the same single comparison value |
| Cmax effect | Mean reduction about 29% | Reduction about 18–50% in food-effect studies |
| Can be taken with or without food under current label? | Product instructions should be followed | Yes |
Vardenafil has an additional formulation issue that makes broad statements about its pharmacokinetics potentially misleading. In addition to conventional film-coated tablets, vardenafil is available in an orally disintegrating tablet formulation with its own administration and exposure characteristics.
Current orally disintegrating vardenafil labeling explicitly states that the ODT is not interchangeable with the 10 mg film-coated tablet because it produces higher systemic exposure. In a comparative study, mean vardenafil Cmax was approximately 15 percent higher and AUC approximately 44 percent higher with the orally disintegrating product.
The ODT is also taken without liquid. A high-fat meal did not affect its AUC or Tmax in the cited healthy-volunteer study, although Cmax was reduced by about 35 percent. This is why statements about 'vardenafil food effects' should identify the formulation rather than assuming that all vardenafil products behave identically.
| Vardenafil Product Feature | Film-Coated Tablet | Orally Disintegrating Tablet |
|---|---|---|
| Dosage form | Conventional oral tablet | Orally disintegrating tablet |
| Interchangeable at the same nominal strength? | Not automatically | Label states it is not interchangeable with 10 mg film-coated tablet |
| Relative systemic exposure | Reference formulation in comparative study | Higher exposure |
| Administration with liquid | Conventional oral administration | Taken without liquid |
| High-fat meal effect | Cmax can be reduced | AUC and Tmax unchanged in study; Cmax reduced about 35% |
Both sildenafil and vardenafil depend substantially on CYP3A-mediated hepatic metabolism, creating an important class-level similarity in their interaction potential. Strong or moderate CYP3A inhibitors can increase systemic exposure to either medicine, although the magnitude of the interaction and the resulting label instructions are drug-specific.
Sildenafil is cleared predominantly through CYP3A, with CYP2C9 serving as a minor pathway. Its major circulating N-desmethyl metabolite remains pharmacologically active and contributes to the overall activity profile.
Vardenafil is metabolized predominantly by CYP3A4, with contributions from CYP3A5 and CYP2C isoforms. Its major circulating M1 metabolite has approximately 28 percent of the parent drug's in-vitro PDE5 inhibitory potency and accounts for only a minority of total pharmacological activity. Sildenafil-specific metabolism is covered on sildenafil metabolism and sildenafil and CYP3A4.
| Metabolic Feature | Sildenafil | Vardenafil |
|---|---|---|
| Major pathway | CYP3A | CYP3A4 |
| Secondary CYP contribution | CYP2C9 | CYP3A5 and CYP2C isoforms |
| Major circulating metabolite | N-desmethyl sildenafil | M1 |
| Metabolite retains PDE5 activity | Yes | Yes, but substantially less potent than parent vardenafil |
| CYP3A interactions relevant | Yes | Yes |
Both drugs are selective for PDE5 relative to other phosphodiesterases, but their in-vitro selectivity profiles are not identical. Sildenafil labeling describes approximately 10-fold greater potency for PDE5 than PDE6, while vardenafil labeling reports greater than 15-fold selectivity for PDE5 relative to PDE6.
Both profiles also show much greater selectivity for PDE5 over several other phosphodiesterase subtypes. These data help demonstrate that shared PDE5 inhibition does not mean the molecules interact with every related enzyme in exactly the same way.
The values come from individual product-label in-vitro studies rather than one standardized clinical head-to-head experiment. They should therefore be interpreted as molecular pharmacology data, not as a direct ranking of clinical effectiveness or tolerability.
| Selectivity Feature | Sildenafil | Vardenafil |
|---|---|---|
| Primary target | PDE5 | PDE5 |
| PDE5 vs PDE6 selectivity | Approximately 10-fold | Greater than 15-fold |
| Identical PDE-family profile? | No | No |
| Selectivity alone proves clinical superiority? | No | No |
One product-label difference that should not be hidden inside a generic class discussion is vardenafil's QT-interval warning. Current vardenafil labeling contains a specific section on congenital or acquired QT prolongation based on clinical pharmacology and postmarketing data.
The label advises that this information be considered in patients with known QT prolongation or medicines that prolong the QT interval, and states that patients taking certain Class IA or Class III antiarrhythmic drugs or those with congenital QT prolongation should avoid vardenafil.
This is a vardenafil-specific labeling characteristic within the comparison rather than a general statement about all PDE5 inhibitors. It illustrates why medicines with the same primary target still require their own product-specific safety review.
| Label Dimension | Comparison Meaning |
|---|---|
| Vardenafil QT warning | Specific labeling consideration |
| Congenital QT prolongation | Identified in vardenafil labeling as an avoidance context |
| Certain Class IA / III antiarrhythmics | Identified in vardenafil labeling as an avoidance context |
| Class membership replaces individual label review? | No |
Vardenafil is the active pharmaceutical ingredient, while Levitra is a brand name historically associated with vardenafil film-coated tablets. A search for sildenafil versus Levitra is therefore fundamentally a sildenafil-versus-vardenafil comparison rather than a comparison with another active drug.
Brand terminology should nevertheless remain separate from formulation terminology. Vardenafil products can differ in dosage form and labeling, and an orally disintegrating vardenafil product should not simply be treated as interchangeable with a film-coated Levitra-type tablet.
The same active-ingredient-versus-brand distinction applies on the sildenafil side. For a broader explanation of sildenafil product naming, see sildenafil brand names.
| Term | Identity |
|---|---|
| Sildenafil | Active pharmaceutical ingredient |
| Vardenafil | Active pharmaceutical ingredient |
| Levitra | Vardenafil brand context |
| Vardenafil ODT | Separate orally disintegrating product formulation |
Median Tmax values of approximately 60 minutes for both drugs describe population distributions rather than a guaranteed peak time for every person. Individual absorption, meal conditions, metabolic activity, interacting medicines and study sampling schedules can all change the observed concentration-time profile.
The same principle applies to clinical response. Two individuals with similar plasma timing can experience different pharmacodynamic responses because exposure is only one part of the overall mechanism.
This is why similar median Tmax and half-life values should not be translated into a claim that sildenafil and vardenafil are clinically interchangeable. Sources of variation on the sildenafil side are discussed on sildenafil PK variability.
| Variable | Potential Effect |
|---|---|
| Gastrointestinal absorption | Can change early exposure |
| Food conditions | Can alter peak-concentration behavior |
| CYP activity | Can alter systemic exposure |
| Interacting medicines | Can modify pharmacokinetics or blood-pressure effects |
| Pharmacodynamic sensitivity | Can alter response at similar exposure |
Sildenafil and vardenafil are among the closer PDE5-inhibitor comparisons from a basic timing perspective. Both have a median fasting Tmax of about one hour, both have terminal half-lives in roughly the 4-to-5-hour range and both use an as-needed oral ED framework centered around approximately one hour before sexual activity.
The meaningful differences emerge beneath those similarities. Their absolute bioavailability differs substantially, high-fat meals affect their concentration profiles differently, their metabolites and PDE selectivity are not identical, and vardenafil has formulation-specific distinctions such as a non-interchangeable orally disintegrating product and a specific QT-related labeling consideration.
The result is neither 'the same drug' nor an obvious winner-versus-loser comparison. They are related PDE5 inhibitors with overlapping timing characteristics but enough pharmacokinetic and product-level differences to require separate interpretation.
| Comparison Question | Interpretation |
|---|---|
| Do they belong to the same class? | Yes. Both are PDE5 inhibitors. |
| Are they the same active ingredient? | No. |
| Is their median fasting Tmax similar? | Yes — about 60 minutes for both. |
| Are their terminal half-lives broadly similar? | Yes — about 4 hours vs about 4–5 hours. |
| Is absolute oral bioavailability identical? | No — approximately 41% for sildenafil and 15% for vardenafil. |
| Are their food effects identical? | No. |
| Does vardenafil formulation matter? | Yes. Film-coated and orally disintegrating products have different exposure characteristics. |
| Does this comparison establish a universal preferred medicine? | No. |
Both are PDE5 inhibitors with broadly similar fasting Tmax and terminal half-life values, but they are different active ingredients with different bioavailability, food effects, metabolites, selectivity profiles and product characteristics.
Their labeled fasting pharmacokinetic data are similar. Sildenafil reaches Cmax within approximately 30 to 120 minutes with a median Tmax of about 60 minutes, while vardenafil reaches Cmax within approximately 30 minutes to 2 hours with the same median of about 60 minutes.
Yes. Sildenafil has a terminal half-life of about 4 hours, while vardenafil and its major metabolite have terminal half-lives of approximately 4 to 5 hours.
No. Tmax measures the timing of peak plasma concentration, while onset describes the beginning of an observable pharmacodynamic effect. Similar median Tmax values do not guarantee identical individual onset.
Current labeling reports mean absolute oral bioavailability of about 41% for sildenafil and approximately 15% for vardenafil. These percentages describe systemic availability and should not be interpreted as direct measures of effectiveness.
Yes. A high-fat meal delays sildenafil Tmax by about 60 minutes on average and lowers Cmax by about 29%. Food-effect studies of film-coated vardenafil reported Cmax reductions of approximately 18% to 50%.
They share the same broad mechanism of PDE5 inhibition and enhancement of NO-cGMP signaling, but they are different molecules with distinct pharmacokinetic and selectivity profiles.
Levitra is a brand context for vardenafil. Vardenafil is the active pharmaceutical ingredient.
No. Current labeling specifically states that vardenafil orally disintegrating tablets are not interchangeable with 10 mg film-coated vardenafil tablets because the ODT produces higher systemic exposure.
Yes. Current vardenafil labeling contains a specific warning concerning congenital or acquired QT prolongation and certain QT-prolonging antiarrhythmic medicines.
Both depend substantially on CYP3A metabolism, but their full pathways differ. Sildenafil also uses CYP2C9 as a minor route, while vardenafil has contributions from CYP3A5 and CYP2C isoforms and forms a different active metabolite.
This pharmacological comparison does not establish a universal preferred medicine. Sildenafil and vardenafil have similar timing characteristics in several respects but differ in exposure, food effects, formulation and product-specific labeling.