This page is completely about Viagra.
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Because Viagra lowers blood pressure, your doctor will evaluate your overall medical condition to determine if Viagra, in combination with sexual activity, could adversely affect you. It is important to contact your health care provider immediately if your erection lasts longer than 4 hours. Men for whom sexual activity is inadvisable may not be good candidates for Viagra. Men who have medical conditions that may cause a sustained erection such as sickle cell anemia, leukemia or multiple myeloma or who have an abnormally shaped penis may not be able to take Viagra. There are several medications that are known to interact with Viagra, so be sure to tell your doctor about all medications you are taking including those you can get without a prescription.