Anxiety-induced failure in erectile response to intracorporeal prostaglandin-E1 in non-organic male impotence: A new diagnostic approach

Intracavernous injection (ICI) ofprostaglandin-E₁ (PGE₁) is used widely as the first diagnostic test in the study of erectile dysfunction. However, a lack of full erection after a maximal dose is frequent. As well as vascular incompetence, this may be due to stress-induced changes, related to the ICI procedure. The aim of this study was to investigate the influence of emotional disturbances on erectile response to ICI in impotent patients. Initially, 24 young men with non-organic impotence (age 34.6 ± 1.5 years; mean ± SEM) were selected and randomized single-blind to pharmacoerection with PGE₁ alone (20 μg/mL) or a mixture (cocktail) containing 20 μg PGE₁ plus an α-adrenergic receptor blocker, phentolamine (Phe, 0.5 mg/mL). Additional studies were also performed double-blind on 10 men with non-organic impotence (age 37.6 ± 1.2 years) utilizing higher PGE₁ dosages for ICI (25 μg/mL alone or in combination with Phe, 0.5 mg/mL). After a 7-day interval, all subjects were crossed-over to receive the alternative treatment. The presence of emotional disturbances was assessed in all patients by the administration of rapid tests (Stai-X1 and Stai-X1r for state-anxiety before and after ICI, respectively; Stai-X2 for trait-anxiety; Zung-test for depression) at the first and at the remaining (Stai-X1 and Stai-X1r) ICI sessions. ICI with 20 and 25 μg/mL; PGE₁ led to a comparable percentage of patients who reported a valid-for-intromission (VFI) erection (63 and 60%, respectively). In contrast, use of the cocktails significantly increased the percentage of subjects with a VFI (87 and 90% of the total number of patients tested, respectively; p <0.05). Moreover, a strong inverse correlation between state-anxiety scores (Stai-X1) and the erectile response to ICI with 20 and 25 μg PGE₁ was found (r = -0.69, p <0.001); such a correlation was not present in patients who underwent ICI with the cocktails. Two cases of prolonged erection occurred (one after 20 μg PGE₁ and the other after 20 μg PGE₁ plus Phe) which were reversed promptly by the intracavernous injection of metharaminol. It is concluded that the lack of a full erectile response after ICI with PGE₁ can be related to the presence of a high 'state-anxiety' in the patients. In such patients, a VFI erectile response can be induced by the administration of a cocktail test-dose.