The efficacy and safety of topical 5% methimazole vs 4% hydroquinone in the treatment of melasma: A randomized controlled trial

Abstract

BACKGROUND: The management of melasma is still challenging, and new treatment modalities with favorable side effect profile are required. Methimazole, a peroxidase inhibitor, seems to have a beneficial effect in the management of melasma but there is a paucity of studies for evaluation of its efficacy. This double-blinded trial was aimed to evaluate the efficacy and safety of methimazole vs hydroquinone 4% which is the gold standard treatment in the management of melasma. METHODS: Fifty patients with melasma were enrolled and randomly divided into two groups to receive 4% hydroquinone or 5% methimazole once daily for 8 weeks. Forty patients completed the study. The clinical response was assessed at 4th, 8th, and 12th weeks after treatment by MASI score, patient satisfaction, and physician scores. RESULTS: Both groups showed a reduction in the MASI score at the 8th week which was more significant in hydroquinone group but higher relapse rate was also observed in this group after discontinuing the drug. The side effects were similar between groups. Also, patient and physician satisfaction scores were also more in favor of hydroquinone 4%. CONCLUSION: Methimazole could be an alternative treatment of melasma alone or in combination with other depigmenting drugs. Although not as effective as hydroquinone, the noncytotoxic and nonmutagenic aspects of methimazole may make it a promising alternative for the treatment of melasma.