Israeli research showing that Pfizer’s blockbuster erectile-function medication Viagra can cause risky side effects in men who have had a stroke have induced Wolfson Medical Center researchers to determine whether the competing drug, GlaxoSmithKline’s Cialis, has the same effect.Doctors at the Holon hospital have invited men who underwent a stroke but want to continue to enjoy normal sex lives to enlist for the study. Prof. Yair Lempel and Prof. Motti Lorberboim on Sunday asked residents of the area to join the study, which will be conducted during the next few months.Lempel, head of the neurology department and Lorberboim, director of the nuclear medicine department, said that they recently studied the brain function of men who had undergone strokes and found the taking of the anti-impotence drug Viagra can cause migraines and a reduction of blood flow in those brain regions involved in strokes. At the same time, men who had not had a stroke did not suffer any such brain function changes.No comment was received from Pfizer-Israel about the new Israeli research on Viagra.When they measured blood flow in the brain in stroke patients taking Viagra and found it had declined, Lempel and Lorberboim decided to study men taking Cialis, the competing drug whose basic molecule is somewhat different than Viagra’s to “relieve the large group of men who have had a stroke but are not willing to forgo their sex lives.”Lorberboim said that men who participate in the study will be able to tell from the first session whether Cialis harms their brain function. “Using advance brain mapping, we can measure blood flow in various brain areas and know whether it is normal or slow.”A cerebral vascular event, he continued, can cause harm to the blood vessels to suit themselves to the new situation, thus they are unable to regulate the amount of blood that passes through them.The doctors said that if Cialis is not involved in this problem, it could be an alternative to Viagra. Lempel and Lorberboim called on residents of Holon, Bat Yam and environs who are ready to come for periodic testing over the coming months to call Smadar at (03) 502-8513 or Liat at (03) 502-8540.