carbimazole / propylthioruacil in thyrotoxicosis

Last reviewed 01/2018

Either carbimazole or propylthiouracil are prescribed in high doses initially - carbimazole 15 to 40 mg per day; propylthiouracil 200-400 mg per day. This single dose promotes compliance. Treatment may then either follow a gradual dose titration regime, or a block and replace regime. 'Long-term remission rates with two regimens are similar.'

Symptomatic improvement is often detected within 3-4 weeks and normal T3 and T4 values are achievable within 2-3 months.

Treatment is usually continued for 18 months. Over 50% relapse within 2 years with a small continuing relapse rate thereafter. Most relapses occur within 4 years.