Short answer: Vardenafil (the drug in Levitra) and sildenafil (Viagra) are PDE5 inhibitor tablets for erectile dysfunction, both taken about an hour before sex, at most once a day.12 Vardenafil usually starts at 10 mg and sildenafil at 50 mg. The vardenafil label adds a QT-interval warning. Neither label reports a trial against the other.
| Vardenafil | Sildenafil (Viagra) | |
|---|---|---|
| Tablet strengths | 2.5, 5, 10 or 20 mg1 | 25, 50 or 100 mg2 |
| Usual start | 10 mg about 60 minutes before sex1 | 50 mg about 1 hour before (30 minutes to 4 hours)2 |
| Dose range | 5 mg to 20 mg; some CYP3A4 inhibitors cap it at 2.5 or 5 mg1 | 25 mg to 100 mg; 25 mg with ritonavir, no more than once in 48 hours2 |
| Lower start considered | Age 65 and older, moderate liver impairment, alpha-blockers (5 mg)1 | Over 65, liver impairment, severe kidney impairment, alpha-blockers (25 mg)2 |
| Food | High-fat meals lowered the peak by 18% to 50%1 | May take a little longer after a high-fat meal2 |
| Headache | 15% vs 4% on placebo1 | 16% (flexible-dose) to 28% (100 mg fixed) vs 4% to 7%2 |
| Flushing | 11% vs 1%1 | 10% to 19% vs 1% to 2%2 |
| Stopped for side effects | 3.4% vs 1.1% on placebo1 | 2.5% vs 2.3% on placebo2 |
| Extra warning | QT prolongation1 | Do not combine with Revatio (sildenafil for lung blood pressure)2 |
Vardenafil is the drug in Levitra. There is no current Levitra-brand label on DailyMed, so this page uses Teva's generic film-coated vardenafil label in the same strengths. The orally disintegrating tablet (Staxyn) is a different product with different dosing.1
In vardenafil's pooled trials of 5, 10 or 20 mg, headache was 15% vs 4% on placebo, flushing 11% vs 1% and stuffy nose 9% vs 3%.1 In Viagra's flexible-dose trials, which match how it is usually taken, headache was 16% vs 4%, flushing 10% vs 1% and indigestion 7% vs 2%; abnormal vision, mostly a color tinge, was 3% vs 0%.2 These numbers come from separate trials with different people, lengths and methods, so they are not a head-to-head comparison.
The right tablet and dose is a call for your prescriber. More detail: vardenafil side effects, Viagra side effects, the vardenafil and Viagra dosing schedules, and the Vardenafil and Sildenafil guides.