Antithyroid treatment: a personal series.

Introduction Since the introduction of thiouracil in 1943 antithyroid treatment for thyrotoxicosis has increased widely and has proved safer and more effective in carefully selected cases as the years have passed. Since 1951 carbimazole has been highly favoured in this country, being considered the least toxic agent in large-scale surveys (Burrell, Fraser & Doniach, 1956). Later (Willcox, 1962), it was shown that, with careful personal selection of suitable cases and with personal dosage control, fifty-three (64%) of eighty-three cases were successfully treated, without relapsing, with methyl thiouracil and fifty-five (82%) of sixty-seven cases with carbimazole. Fifty-eight per cent of this group had been followed up for 5 years or longer. The relapse rate in the two groups was 22% and 9% respectively, a relapse being defined as recurrence of toxic features occurring more than 6 months after completion of a course of treatment. The duration of treatment aimed at was 1 year but in cases in which loss of weight and other symptoms quickly recurred following withdrawal of the drug, treatment was necessarily continued for variable periods, as long as 2 years in a few cases. The present follow-up study is an analysis of all cases personally selected for treatment from cases sent for consultation from 1948 until December 1965. In the early period, 1948-53, methyl thiouracil was used and since 1953 carbimazole alone.