Higher than conventional doses of carbimazole in the treatment of thyrotoxicosis.
In order to ascertain whether higher than conventional doses of carbimazole achieve more rapid control of thyrotoxicosis, 30 thyrotoxic patients were alternately allocated into two groups, group 1 (15 subjects) receiving a conventional starting dose of 45 mg orally daily and group 2 (15 subjects) a dose of 100 mg orally. In addition to weekly estimations of serum T4, T3, free T4, free T3 and TSH, the systolic time intervals ratio (STI), a measure of left ventricular contractility, was calculated as an accurate measure of peripheral thyroid hormone activity, the study end-point being a normal STI (0.26-0.32). None of the individuals studied experienced side-effects during the study period. Mean pre-treatment STI values for the two treatment groups were the same at entry (0.20). The mean recovery times for STI was 4.4 weeks (SE 0.3) in the high dose group and 5.9 weeks (SE 0.4) in the low dose group (P = 0.0037). There was a definite trend towards a shorter recovery time for free T3 in the higher dose group (P = 0.057) but no apparent differences for T4, T3 and free T4. Higher than conventional doses of carbimazole may be advisable in the initial treatment of severe thyrotoxicosis.
O'Malley
B P
BP
Department of Pharmacology, University of Leicester, UK.
Rosenthal
F D
FD
Northover
B J
BJ
Jennings
P E
PE
Woods
K L
KL
D000284:Administration, Oral; D000328:Adult; D002231:Carbimazole / Q000008:administration & dosage* / Q000627:therapeutic use; D006801:Humans; D008875:Middle Aged; D013971:Thyrotoxicosis / Q000188:drug therapy*
D002231:Carbimazole