Tadalafil for Treatment of Priapism in Men With Sickle Cell Anemia

Inclusion Criteria: * All men (18 years of age and older) with actively recurrent ischemic priapism, defined as multiple, self-limited erectile events (characteristically less than 3 hours in duration) occurring repeatedly at least twice a week in the absence of sexual interest or desire may be considered for enrollment * Able to swallow whole tablets equivalent to capsule size 0 * Available for protocol-specified visits and procedures Exclusion Criteria: * History of refractory-type priapism * History of drug or alcohol abuse * Currently smokes or has a 20 pack-year history of cigarette smoking * Take any medications called "nitrates" * History of acute or chronic depression * History of heart problems such as angina, heart failure, irregular heartbeats or myocardial infarction * History of low blood pressure or high blood pressure that is not controlled * History of diabetes, liver problems, or kidney problems * A glomerular filtration rate of \<50ml/min. * History of retinitis pigmentosa or severe vision loss, including a condition called NAION * History of stomach ulcers * History of HIV, multiple myeloma, or leukemia * History of Peyronie's disease * History of spinal trauma or surgery to the brain or spinal cord * Any contraindications to Cialis use * Currently participating in another clinical investigation