Pharmacokinetics of propranolol in B-thalassemia/Hb E

Propranolol is widely used for the treatment of heart diseases in thalassemic patients. Hyperbilirubinemia and pathophysiological changes in the patients may alter pharmacokinetics of the drug. To define the pharmacokinetics of propranolol in thalassemic patients compared to with healthy volunteers, ten thalassemic patients and healthy subjects were enrolled in this study. All subjects received a single oral dose of 40 mg propranolol. Blood samples were collected after dosing. Propranolol and propranolol-lucuronide concentrations in plasma were determined using HPLC method. Pharmacokinetic parameters of the drug were calculated using one-compartment model. Compared with healthy subjects, thalassemic patients showed the statistically significant increase of maximum concentration, area under concentration time curve and longer half-life of propranolol. In addition, the area under concentration time curve of propranolo-glucuronide was significantly lower in the patients compared with those of healthy subjects. Blood pressure as well as heart rate were recorded during the study period. The significant reduction of systolic and diastolic blood pressure were found in the patients more than in healthy subjects. The results suggested that starting dose of propranolol should be low in thalassemic patient.