Efficacy and safety of methimazole ointment for patients with hyperthyroidism

• Efficacy and safety of methimazole ointment on hyperthyroidism was observed.
• Methimazole ointment has similar clinical efficacy as oral tablets.
• Methimazole ointment causes fewer systemic adverse effects.

Oral methimazole has been widely used to treat hyperthyroidism, but its usage is restricted by its adverse systemic effects. The aim of this study was to investigate the efficacy and safety of methimazole ointment for the treatment of hyperthyroidism. One hundred forty-four subjects with hyperthyroidism were initially enrolled. These patients were initially divided into two groups and given the following treatments for 12 weeks: patients in group A received 5% methimazole ointment applied to the skin around the thyroid and an oral placebo; and patients in group B received methimazole tablets and placebo ointment. One hundred thirty-one subjects were included in the final analysis. Therapeutic efficacy was assessed via the levels of free triiodothyronine and thyroxine in the serum and by biweekly monitoring of the symptoms of thyrotoxicosis. Adverse effects were recorded. Fifty-nine (89.40%) patients in group A and 57 (87.69%) patients in group B were euthyroid and experienced alleviation of thyrotoxicosis symptoms (complete control; p > 0.05). The median times required to achieve complete control for the patients in the two groups were 6.5 weeks and 6.4 weeks for groups A and B, respectively (p > 0.05). Systemic adverse effects (e.g., rash, liver dysfunction, leucopenia, etc.) were significantly less common in group A (1.5%) than in group B (12.3%; p < 0.05). This study showed that methimazole ointment has a clinical efficacy similar to that of oral tablets, but methimazole ointment caused fewer systemic adverse effects in patients with hyperthyroidism.