Pinpointing erectile dysfunction cause offers little help in drug choice

New York-Differential diagnosis of erectile dysfunction doesn't appear worth the effort when selecting a drug for treatment: No meaningful difference in the effect of the three available phosphodiesterase type-5 inhibitors was seen among men in a clinical trial, regardless of the cause of their ED, according to Hartmut Porst, MD.

Despite that small range, individual patient preferences for a particular PDE-5 inhibitor can differ widely, study results showed.

Preference not linked to etiology

After the diagnosis was confirmed, each man was given the three PDE-5 inhibitors in an arbitrary sequence for at least six attempts at sexual activity: sildenafil citrate (Viagra), 50 mg, or either tadalafil (Cialis), 10 mg, or vardenafil (Levitra), 10 mg. The men were given permission to increase their dosage after two unsatisfactory attempts.

Results were scored according to the cause of erectile dysfunction. Little difference was seen in the IIEF-EF domain scores for men with arteriogenic ED: 21.54 for sildenafil, 23.67 for tadalafil, and 23.38 for vardenafil. Scores for veno-occlusive ED were similarly close: 21.34 for sildenafil, 22.43 for tadalafil, and 21.88 for vardenafil.

However, some marked differences were reported in preferences expressed by the men. Of those with arteriogenic ED, 15% said they preferred sildenafil, while 47% preferred tadalafil, and 29% preferred vardenafil; the remaining 9% expressed no preference.

Of men whose ED was veno-occlusive, 10% said they preferred sildenafil, 42% preferred tadalafil, and 27% preferred vardenafil, with 21% expressing no preference. Similarly, in men with ED of mixed origin, 14% preferred sildenafil, 44% preferred tadalafil, 28% preferred vardenafil, and 14% expressed no preference.

The preference rates for ED of psychogenic origin were sildenafil, 17%; tadalafil, 45%; and vardenafil, 30%, with 8% of men expressing no preference.

"What we are doing in prescription has no basis in diagnosis," Dr. Porst said.

In his clinical practice, he said he gives his patients any one of the medications, sometimes prescribing a combination, until the desired effect is achieved.