A Trial for Prevention of Recurrent Ischemic Priapism in Men With Sickle Cell Disease: A Pilot Study

Inclusion Criteria: * Men with confirmed diagnosis of HbSS or Hb beta zero thalassemia * Ages between 18 to 40 years * Eligible study participants must receive care in an SCD clinic at AKTH and MMSH at the time of the recruitment * Participants must commit to long-term follow-up and taking the trial medications * At least 3 episodes of priapism, each lasting for no less than an hour in the past 6 months. * Adequate renal and hepatic function (baseline liver enzymes and synthetic activities should be no more than four-fold above the reference ranges for Aminu Kano Teaching Hospital (AKTH). These are the ranges obtained in AKTH: Alkaline phosphatase: 42-110 U/L, Alanine transaminase: 4-34 U/L, Aspartate transaminase: 7-45 U/L, Albumin: 32-52 g/L, and Globulin: 32-43 g/L. Exclusion Criteria: * Individuals already enrolled in another clinical trial * eGFR \<50ml/min * Liver cirrhosis based on clinical history, laboratory data or both * Previously known pulmonary hypertension based on TRJV greater than 3.0 m/sec * Contraindications to tadalafil (arrhythmia, severe liver disease, concurrent use of nitrates, etc.) or hydroxyurea (leg ulcer, hypersensitivity, etc.). * Patients who have penile prosthetic implants or shunts or any other surgical procedure on the penis * Patients who have taken drugs/medications that may induce priapism over the 14 weeks before trial: * Medications injected directly into the penis to treat erectile dysfunction, such as alprostadil, papaverine, phento…