Pharmaco-induced erections for penile color-duplex ultrasound: oral PDE5 inhibitors or intracavernosal injection?

To prospectively compare the clinical responses and penile color-duplex ultrasound (PCDU) results of oral PDE5 inhibitors (PDE5-Is) with papaverine intracavernosal injection (ICI) and to evaluate whether PDE5-Is could be used as alternatives to vasoactive agent injections, 25 ED patients underwent PCDU three times with an interval of at least 1 week, using different pharmacological induction: ICI mode (30-60 mg papaverine), sildenafil mode (100 mg sildenafil) and tadalafil mode (20 mg tadalafil). The preference of the patients was collected when all tests were completed. No significant differences were found in peak systolic velocity and acceleration time among all three modes. However for the ICI mode, end diastolic velocity of the right cavernosal artery was significantly higher than those of the sildenafil and tadalafil modes 5 min after erection induction, and at 15 min it became lower than those of two PDE5-I modes. Consequently, resistance index of the right cavernosal artery in ICI mode was reversed at 5 and 15 min. In all, 60.0 and 56.0% patients managed to reach full erection in PDE5-Is modes, which was significantly lower than in ICI mode (80.0%). Therefore, although PDE5-Is and papaverine ICI showed similar effects on PCDU parameters in detecting arterial ED, more patients had better clinical responses to ICI, and oral PDE5-Is administration still showed some pitfalls in practical use.