en Pediatric Hematology & Oncology Pediatric Hematology & Oncology پژوهشي Original Article Background: Hemoglobin S arises is the result of a point mutation (A-T) in the sixth codon on the -globin gene on chromosome 11 causing sickle cell anemia. The presence of fetal hemoglobin in infancy plays a relatively protective role for vaso-occlusive symptoms that are the major contributor for the morbidity and mortality among patients with sickle cell anemia. hydroxyurea, an s-phase-specific and non-DNA-hypomethylating chemotherapeutic agent is capable of inducing HbF synthesis. Materials and Methods: We reviewed the records of 28 sickle cell anemia patients, aged 4-52 years, treated with hydroxyurea to study the drug’s side effects. Results: In our study, the most common adverse effect was dermatologic complication which occurred in 15 patients (53.5%). The gastrointestinal side effects were nausea, vomiting, abdominal pain and anorexia occurring in 3 patients 10.7%. The neurologic adverse effects were uncommon and occurred in 4 patients (14.3%). Conclusion: Side effects of hydroxyurea were common but mild to moderate, benign and transient. Starting a low dose of hydroxyurea (10 mg/kg per day) and increasing the dose slowly in pediatric and adult patients with sickle cell anemia can be tolerated well, without serious side effects. Keywords: Side effect, hydroxyurea, sickle cell, anemia. Side effect, hydroxyurea, sickle cell, anemia. 51 53 http://ijbc.ir/browse.php?a_code=A-10-1-17&slc_lang=en&sid=1 A Ghasemi 10031947532846001143 10031947532846001143 No B Keikhaei 10031947532846001144 10031947532846001144 Yes SJ Sayedi 10031947532846001145 10031947532846001145 No