title: Regional cerebral blood flow following single-dose and continuous-dose tadalafil after stroke.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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).
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Nuclear Medicine, Edith Wolfson Medical Center, Holon, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Lorberboym
authors.forename: E
authors.initials: E
authors.lastname: Makhline
authors.forename: Y
authors.initials: Y
authors.lastname: Lampl
mesh_terms: D000328:Adult; D000368:Aged; D002243:Carbolines / Q000008:administration & dosage* / Q000009:adverse effects*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D007172:Erectile Dysfunction / Q000188:drug therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D020521:Stroke / Q000150:complications / Q000000981:diagnostic imaging*; D000068581:Tadalafil; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D002243:Carbolines; D019275:Radiopharmaceuticals; D014665:Vasodilator Agents; D019690:Technetium Tc 99m Exametazime; D000068581:Tadalafil
keywords: HMPAO; SPM; Statistical Parametric Mapping; cerebral blood flow; single-photon emission computed tomography; stroke; tadalafil