title: Increased clearance of propranolol in thyrotoxicosis.
abstract: The pharmacokinetics of oral propranolol were studied during chronic treatment in six patients when thyrotoxic and again when euthyroid. The mean total plasma propranolol steady-state concentration was 42% lower when the patients were thyrotoxic. After treatment of thyrotoxicosis there was a fall (P less than 0.05) in the oral clearance of both total (4.2 +/- 0.6 to 2.7 +/- 0.4 L/min, mean +/- SEM) and free (30.5 +/- 4.7 to 25.5 +/- 4.1 L/min) propranolol although the half-life of propranolol did not change significantly. The free fraction of propranolol was higher (p less than 0.05) in the thyrotoxic (14.2% +/- 1.3%) than in the euthyroid (11.4% +/- 0.8%) state. These results suggest that the pharmacokinetics of propranolol are significantly altered in thyrotoxicosis.
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D001835:Body Weight; D005260:Female; D006207:Half-Life; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood* / Q000188:drug therapy; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D011433:Propranolol / Q000008:administration & dosage / Q000097:blood*
chemical_list: D011433:Propranolol