Effect of Lugol's solution on I therapy efficacy in Graves' disease.

PURPOSE

Lugol's solution could control thyroid function and suppress I uptake in hyperthyroidism. This study aimed to investigate the appropriate time to withdraw Lugol's solution before I therapy (RIT) in Graves' disease (GD) patients, and how this should influence I uptake and RIT outcome.

METHODS

Two groups (125 cases and 1805 cases) of GD patients received RIT, who were pre-treated with and without Lugol's solution (RI-CI group and RI group). The RI-CI group was further divided into the following sub-groups depending on the duration span between Lugol's solution withdrawal and RIT: sub-group A, 4-7 d (n = 49); sub-group B, 8-14 d (n = 41); and sub-group C, 15-30 d (n = 35). The highest radioactive iodine uptake rate (RAIU), effective half-life (T), TRAb, and free triiodothyronine (FT) and free thyroxine (FT) levels were compared, and therapeutic outcome was evaluated.

RESULTS

There were no significant differences in RAIU, TRAb, and T among the four sub-groups (P > 0.05). Both FT and FT levels in sub-groups A and B were lower than those in group RI and sub-group C (P < 0.05). The outcome of non-hyperthyroidism (euthyroidism + hypothyroidism) in groups RI-CI and RI was significantly different at post-RIT month 1 and 3 (P < 0.05). However, intergroup differences at 6 and 12 months were not significant (P > 0.05).

CONCLUSIONS

Withdrawal of Lugol's solution 4-7 or 8-14 d before RIT does not influence I uptake and RIT efficacy in GD. Moreover, in order to avoid a rapid increase in thyroid hormone levels at the same time, Lugol's solution should be withdrawn 4-7 d before RIT.