Vardenafil
Vardenafil is a potent second-generation PDE5 inhibitor structurally similar to sildenafil but roughly an order of magnitude more potent on a molar basis, so effective doses are lower. It offers a similar on-demand profile for erectile dysfunction and is sometimes chosen when sildenafil is ineffective or poorly tolerated.
01 Overview
Vardenafil selectively inhibits PDE5 with high potency. Clinically its efficacy is comparable to sildenafil, with a similar onset (~30-60 minutes) and a half-life of about 4-5 hours. It carries a modest QT-prolongation signal, so it is avoided in those with QT risk or on QT-prolonging drugs, and an orally disintegrating formulation exists.
In PED use it occupies the same niche as sildenafil — on-demand erectile support and vasodilation — and is chosen by some users who respond poorly to sildenafil. The nitrate contraindication and alpha-blocker interaction apply, and the QT consideration is a point of difference from the other agents.
02 Mechanism
High-potency selective inhibition of PDE5, increasing cGMP and enhancing nitric-oxide-mediated cavernosal vasodilation.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Low | 5 mg | Oral | Starting dose in the elderly or on interacting drugs. |
| Erectile function | 10–20 mg | Oral | Taken ~30-60 min before activity; 20 mg is the label ceiling. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Improved erectile functionEfficacy comparable to sildenafil in restoring erectile function. | ~70-80% responder rate | Clinical | |
| High potency at low doseLower milligram doses achieve equivalent PDE5 inhibition. | ~10x molar potency vs sildenafil | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Headache and flushingVasodilatory headache, flushing and nasal congestion. | Mild | Very common | Clinical | |
| QT prolongationModest QT-interval prolongation, a distinguishing feature versus other PDE5 inhibitors. | Moderate | Uncommon | Clinical | |
| Nitrate interaction (severe hypotension)Additive, potentially fatal hypotension with nitrates or NO donors. | Life-threatening | Rare but potentially fatal | Clinical |