What the four trials measured
Levitra was studied in four major double-blind, randomized, placebo-controlled, fixed-dose trials in 2,431 men aged 20 to 83. The doses were 5 mg, 10 mg, and 20 mg. Two trials were in a general erectile-dysfunction population. One was in men with diabetes. One was in men after prostatectomy. Men took the tablet as needed, without a meal rule, and the primary look was at 3 months.
The shared endpoints were the erectile-function domain of the International Index of Erectile Function, scored from 0 to 30, plus two diary questions: SEP2, an erection sufficient for penetration, and SEP3, an erection maintained long enough for intercourse. Across the four trials the mean starting erectile-function score was 11.8, and Levitra beat placebo on all three endpoints. That sentence is the shape of the evidence. The useful part is which percent belongs to which group.
In the North American general-population trial (762 men), erectile-function scores at 3 months were 18, 21, and 21 on 5 mg, 10 mg, and 20 mg, against 15 on placebo. Ten milligrams and 20 mg landed on the same mean score in that trial. A European trial in 803 men confirmed the pattern. The North American improvement in mean score was still there at 6 months.
SEP2 in that North American trial was 65%, 75%, and 80% on 5 mg, 10 mg, and 20 mg, against 52% on placebo. SEP3 was 51% on 5 mg, 64% on 10 mg, and 65% on 20 mg, against 32% on placebo. The step from 10 mg to 20 mg on SEP3 was one percentage point in this trial. A review that treats 20 mg as a different drug, on this endpoint, is reading past the table.
Diabetes and prostatectomy are different rows
The diabetes trial enrolled 439 men and used 10 mg and 20 mg. SEP3 was 49% on 10 mg and 54% on 20 mg, against 23% on placebo. Erectile-function scores were 17 and 19, against 13. Better than placebo. Not the 64% from the general North American row.
After radical prostatectomy, 427 men, again 10 mg and 20 mg: SEP3 was 37% on 10 mg and 34% on 20 mg, against 10% on placebo. Penetration was 47% and 48%, against 22%. Here 20 mg did not beat 10 mg on the intercourse endpoint. Quoting only the general-population 64% to a man in this group is the wrong review.
A star score is a different count
On 24 October 2026, a UK pharmacy review page for vardenafil displayed a rating of 4.18 out of 5 from 185 customer reviews. That number counts how those customers scored the product on that site. It has no placebo arm, no SEP3, and no QT interval. It is not the North American trial, and it is not a US effectiveness rate.
Personal write-ups sit in the same kind of search. One man's note that the tablet changed his erections, or that a headache was more tolerable than on another drug, is a diary. It cannot be averaged into the 64%. This page does not add anonymous stories of its own.
A comparison guide opened with this search says Levitra, on average, works a little quicker and provides an erection that lasts a little longer than Viagra. The four major trials on the US label compared Levitra with placebo. They did not include a sildenafil arm, so they do not establish that average. How to time the swallowed tablet, including the hour and the high-fat meal, is the Levitra timing note. The access checks are on the vardenafil medicine page.
Headache and flushing, in the label's pooled column
The label's pooled column for controlled trials lists headache in 15% of men on Levitra (N = 2,203) and 4% on placebo (N = 1,199), flushing in 11% and 1%, rhinitis in 9% and 3%, and dyspepsia in 4% and 1%. The same section says headache, flushing, dyspepsia, nausea, and rhinitis showed a dose effect from 5 mg through 20 mg. A review that mentions headache is often describing something the pooled column already shows. It is not, by itself, the heart-rhythm issue.
The QT line a five-star review can skip
In a study of 44 healthy volunteers, a single 10 mg dose produced a placebo-subtracted mean change in the Fridericia-corrected QT interval of 5 milliseconds (90% confidence interval 2 to 8). Gatifloxacin 400 mg alone was about 4 milliseconds. Together, the effects added, and the mean change from baseline was 9 milliseconds (90% confidence interval 6 to 11). The label says the clinical impact of these QT changes is unknown.
The instruction that follows is not unknown. People taking a Class 1A antiarrhythmic (quinidine, procainamide) or a Class III antiarrhythmic (amiodarone, sotalol), and people with congenital QT prolongation, should avoid Levitra. Nitrates and nitric oxide donors remain contraindicated. No safe gap for a later nitrate has been determined. Where the brand and the later melt came from is the Levitra history note. This SPL is the swallowed film tablet. It is not a Staxyn trial report.
The rows worth keeping
| Group, at 3 months | Intercourse endpoint on 10 mg | Same endpoint on placebo |
|---|---|---|
| North American general trial | 64% | 32% |
| Diabetes | 49% | 23% |
| After radical prostatectomy | 37% | 10% |
Ten milligrams is the usual labeled start for most adults, and it is the column these review questions usually mean. Twenty milligrams is a later prescriber step. In the rows above it was not a large step past 10 mg, and after prostatectomy the 20 mg intercourse rate was not higher.
Do not start, stop, or change vardenafil from a library page. A star rating, a forum note, and a placebo-controlled percent are three different kinds of sentence. Bring the one that matches your situation to the clinician who can see the rest of the list.