The aim of this study was to determine whether a course of carbimazole
therapy in higher than normal doses could improve remission rates in
Graves' disease, 77 patients were randomly allocated to one of two tre
atment groups. Group 1 (n=33) received a 12-month course of 60 mg/day
carbimazole. Group 2 (n=44) received 45 mg/day for the first month, 30
mg/day for the second month, and 20 mg/day for the remaining 10 month
s. All patients were started on T3 between 2 and 4 months after commen
cing therapy, to maintain euthyroidism. After carbimazole/T3 therapy w
as withdrawn, patients were followed for either 12 months or until the
y relapsed. A total of 14 patients (five Group 1, nine Group 2) were w
ithdrawn from the study. There was no significant difference in mean t
hyroid hormone levels between the two treatment groups during treatmen
t. TT4 concentrations fell significantly faster during the first 4 wee
ks of treatment in Group 1 patients. Of the 63 patients who completed
the study, 30 relapsed and 33 remained in remission. Of those who rela
psed, 10 (33%) were from Group 1 and 20 (67%) from Group 2. Of those i
n remission, 18 (54%) were from Group 1 and 15 (45%) from Group 2. Hig
h doses of carbimazole were associated with few adverse side-effects a
nd an improved remission rate.