A Double Blind Randomized Trial of Efficacy and Safety of 5% Methimazole Versus 2% Hydroquinone in Patients with Melasma

Background: Melasma is an acquired facial hyperpigmentation that is chronic and resistant to treatment. This study aimed at comparing the therapeutic response and safety of 5% methimazole cream versus 2% hydroquinone cream in Iranian females with melasma. Methods: This was a randomized, controlled, double-blind clinical trial. Fifty-eight patients aged 18 to 50, and who had been clinically diagnosed with melasma were enrolled. They were randomly divided to 2 groups: those treated with 5% methimazole cream and those treated with 2% hydroquinone once nightly for 8 weeks. Their responses to treatment were evaluated using the Melasma area and severity index (MASI), theE score obtained using VisioFace digital photography, and the patients’ ownsatisfaction. Safety wasassessed by measuring thyroid-stimulatinghormone(TSH) levels. For statistical analysis, the SPSS version 16.0 forWindows(SPSS Inc., Chicago, IL) was used. Results: The subjective assessments of methimazole and hydroquinone (patient satisfaction) were as follows: excellent and good, 67.7% for methimazole vs. 70.3% for hydroquinone, and moderate and mild, 32.2% for methimazole versus 29.6% for hydroquinone. The assessments showed no statistical differences between the 2 groups (P = 0.942). At the end of treatment, MASI scores were significantly lower in the methimazole group than in the hydroquinone group (P = 0.042). The VisioFaceE scores were also significantly lower in the methimazole group than in the hydroquinone group (P = 0.049). Serum thyroid stimulating hormone (TSH) levels showed no statistical differences between the 2 groups (P = 0.613). Conclusions: Compared with 2% hydroquinone, topical methimazole was more effective for improving melasma and had no effect on serum TSH levels. Therefore, methimazole could be considered as a first-line or combination therapy for melasma.