Safety profile of long term administration of low dose hydroxyurea in thalassemia intermedia

Background Hydroxyurea therapy in thalassemia intermedia is an off‐label use of this drug. We conducted a retrospective study to determine the safety profile of low dose hydroxyurea in patient with thalassemia intermedia. Methods: We interviewed patients who were 5.5 to 39 years old. A total of 133 patients with thalassemia intermedia were interviewed in person with the use of a questionnaire that incorporated classified adverse reaction of hydroxyurea by organ system. We obtained detailed information about blood counts, liver and renal function test from patients records. Results: The duration of hydroxyurea therapy was between 6 months to 54 months. The mean dose of hydroxyurea was 10.74 mg/kg/day. Use of hydroxyurea was not associated with serious adverse effects. 89 of the 133 patients (66.9%) did not show any identifiable adverse reaction. Among the remainder, the most common unwanted effects was headache (12%) followed by skin pigmentation (7.5%), hair loss (6%), maculo‐papular rash (6%), dizziness (5.25%), anorexia (4.5%), facial erythema (3.25%), nausea and vomiting (1.3%). The rate of discontinuation was zero. All of the adverse reactions were mild, transient and well tolerated. Bone marrow suppression and/or secondary malignancies were not developed in any patient. Conclusions: Hydroxyurea was well tolerated in patients with thalassemia intermedia with minimal adverse reactions. Clinical Pharmacology & Therapeutics (2004) 75 , P58–P58; doi: 10.1016/j.clpt.2003.11.222