Inability to recruit patients into the study.

Propanolol is a beta blocker which has been found to inhibit the ability of epinephrine to upregulate sickle red cell adhesion to laminin and endothelial cells in vitro. The purpose of this pilot study is to administer one dose of propanolol to children with sickle cell disease and to measure pre and post dose red cell adhesion. The hypothesis is that a single dose of propanolol will decrease red cell adhesion to laminin and endothelial cells as compared to baseline.

A similar pilot study has already been conducted in adults and is now being tried in children to gather preliminary data for a grant submission. No safety issues were found in the adult pilot study. This study will evaluate the effect of different doses of propanolol. The risks of this study involve the risks of three (3) blood draws and the risks of propanolol. In order to minimize the risks children with sickle cell disease and asthma will be excluded because asthma is a contraindication to the use of propanolol. In addition, patients will not be hypertensive or bradycardic.

Inclusion Criteria:

1. diagnosis of HbSS or HbSBeta0Thal
2. age 10-17 years
3. Weight 30kg or greater
4. Hb 7mg/dL or greater
5. informed consent

Exclusion Criteria:

1. History of vaso-occlusive crisis during the past 6 weeks, or history of transfusion during the past 3 months.
2. pregnancy
3. history of heart failure, myocardial infarction, asthma, bradyarrythmias, hypotension, thyroid disease, diabetes, renal insufficiency
4. concurrent medications: any antihypertensive medication, diuretics, thyroid replacement medications, any arrythmia medication, insulin, hypoglycaemic medication
5. history of allergy to sulfonamides
6. elevated BUN or creatinine