Viagra Side Effects: viagra can cause headache, one of ten men in tbe clinical trials http://www.medications.com/effect/view/18224 viagra can cause headache, one of ten men in tbe clinical trials developed blinding headaches that grew more severe at higher doses. My bf had terrible headaches connected with taking Viagra. As far Thu, 06 Dec 2007 08:45:44 -0500 http://www.medications.com/effect/view/18224?item=3281 My bf had terrible headaches connected with taking Viagra. As far as I can tell, Extagen doesn't have such side effects. http://www.medications.com/effect/view/18224?item=3281