Evaluation of Optimal Time of Methimazole Discontinuation Before Radio-iodine Therapy in Hyperthyroid Grave's Patients

Iodine therapy is the best treatment for graves disease.Most patients receive methimozale prior to radio-iodine treatment. This may decrease treatment response to iodine therapy.

Some physicians advice to discontinue methimazole 3 days before radioiodine therapy and others prefer longer off - methimazole period which bothers most patients. This study aimed to evaluate optimum time for methimazole discontinuation in graves disease.

Inclusion Criteria:

• age 18-65
• graves disease(TSH<0.1 &increased FT4 & positive TSI
• one or more bartlena criteria for radio-iodine therapy
• 24 hour RAIU>25%
• euthyroidism after methimazole treatment

Exclusion Criteria:

• pregnancy or lactation
• moderate or severe graves ophthalmopathy
• CHF or coronary heart disease
• palpable thyroid nodule
• lithium or amiodarone or lugol or ipodate treatment
• recent imaging with contrast agent
• very large goiter(more than 150 gram)