Overview

The goal of this study is to evaluate if patients with sickle cell disease can achieve a maximum tolerate dose of hydroxuyrea (HU) over a period of 12 months faster with pharmacokinetic testing than the standard of care bloodwork follow-up. Pharmacokinetic test is used to evaluate the process by which drugs are absorbed, distributed in the body, localized in the tissues, and is excreted.

Patient will be a randomized (coin toss method) into 2 groups. Group A will have an increase of their HU dosage with pharmacokinetic results and Group B will have an increase of their HU dosage following the standard of care bloodwork follow-up.

Group C will include patient with sickle cell disease that has been taking HU for at least 12 months and will undergo a pharmacokinetic dosage to check the level of HU only one time.

Eligibility

Inclusion Criteria (Group A and B) :

• Have had confirmed diagnosis of SCD at CHU Sainte-Justine biochemistry lab with hemoglobin electrophoresis.
• Patients with SS, SBThal0.
• Agree to take hydroxyurea for a period of 12 months
• Be between age of 6months old and 18 years old.
• Have consented for participation in the study.

Inclusion Criteria (Group C) :

• Have had confirmed diagnosis of SCD at CHU Sainte-Justine biochemistry lab with hemoglobin electrophoresis.
• Patients with SS, SBThal0.
• Have taken hydroxyurea for a period of at least 12 months, and have received HU at a stable dose and at MTD for at least 6 months.
• Be between age of 6months old and 18 years old.
• Have consented for participation in the study.

Exclusion Criteria:

• Patients with sickle cell genotype other than SS or SBThal0 (SC, SBThal+, SE or SD)
• Patients on chronic transfusion program
• Patients have received a blood transfusion in the last 4 weeks of study enrollment.
• Have received a hematopoietic stem-cell transplantation
• Creatinine \>2x normal for age
• ALT\>2x normal for age
• Sexually active females unwilling to comply with reliable method of birth control
• Pregnancy
• Conditions which in the opinion of the investigator, would compromise participation in the study will be excluded.