technetium-tc-99m-exametazime and Erectile-Dysfunction

Tadalafil is a potent and selective phosphodiesterase type 5 inhibitor that provides effective treatment for erectile dysfunction (ED). The purpose of this study was to explore the effect of a single on-demand dose of tadalafil compared to low-dose continuous administration on regional cerebral blood flow (rCBF), in patients after stroke.. Thirty consecutive male patients (mean age 58.3 ± 7.9 years) with ED and a history of stroke were included in the study. The baseline single-photon emission computed tomography (SPECT) study was performed 15 min after iv injection of 740 MBq Tc-99m-HMPAO (Ceretec; GE Healthcare Ltd. Chalfont St. Giles, UK). Fifteen randomized patients received a single dose of 20 mg tadalafil in the morning, and a second SPECT study was performed 6 h later. Fifteen other patients received 5 mg of tadalafil each morning for seven consecutive days, and the second SPECT study was performed 6 h after the last dose. The imaging data were evaluated using SPM software (Wellcome Department of Cognitive Neurology, University College, London).. Associations between any of the risk factors/comorbidities and the perfusion changes were not detected. All patients showed areas of reduced relative rCBF in the affected hemisphere after tadalafil administration compared to baseline (P < 0.001). No significant difference was found between patients on 5 mg tadalafil and 20 mg dose.. Tadalafil administration after cerebral stroke may be associated with diminished blood flow to areas adjacent to the stroke. The alterations in perfusion suggest a need for caution in prescribing tadalafil to patients with a history of stroke, especially with continuous administration that may impose constant stress on the cerebral circulation.

Topics: Adult; Aged; Carbolines; Cerebrovascular Circulation; Erectile Dysfunction; Female; Humans; Male; Middle Aged; Radiopharmaceuticals; Stroke; Tadalafil; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Vasodilator Agents

Sildenafil citrate is widely used for erectile dysfunction. The present study examined the short-term effects of sildenafil administration in individuals with cerebrovascular risk factors, including patients with a history of stroke.. Twenty-five consecutive male patients with erectile dysfunction and vascular risk factors were included in the study. A perfusion brain SPECT study was performed at baseline and 1 h after the oral administration of sildenafil.. Associations between any of the risk factors and the perfusion scores were not detected, with the exception of stroke. Stroke patients showed significantly more areas with diminished perfusion after sildenafil administration compared to baseline.. In patients with diabetes or hypertension, a dose of 50 mg sildenafil does not appear to produce detrimental effects on cerebral blood flow. However, patients with a history of stroke may be at increased risk of hemodynamic impairment after the use of sildenafil.

Topics: Adult; Aged; Brain Mapping; Cerebrovascular Circulation; Cerebrovascular Disorders; Erectile Dysfunction; Humans; Male; Middle Aged; Phosphodiesterase Inhibitors; Piperazines; Purines; Radiopharmaceuticals; Risk Factors; Sildenafil Citrate; Sulfones; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon