Combined isobutylamido thiazolyl resorcinol and low-fluence Q-switched Nd: YAG laser for the treatment of facial hyperpigmentation: A randomized, split-face study.

Background: Isobutylamido thiazolyl resorcinol (ITR) is a novel anti-tyrosinase recently shown to be effective in the treatment of hyperpigmentation. Low-fluence Q-switched Nd:YAG 1064-nm laser (LFQS) has proven to be effective for various hyperpigmentary conditions. However, there is no study on the efficacy and safety of combined ITR and LFQS treatment.
Objectives: To compare the efficacy and safety of combined ITR and LFQS with LFQS monotherapy for facial hyperpigmentation.
Materials and Methods: Patients with symmetrical facial hyperpigmentation were treated with five sessions of once weekly LFQS on the whole face. One side was randomly treated with ITR and the other side received a placebo cream for 12 weeks. Patients were followed for 8 weeks after the last laser treatment. Relative lightness index (RL*I), Facial Hyperpigmentation Severity Score on the malar area (FHSS _m ), patient satisfaction, recurrence, and adverse events were recorded.
Results: Twenty-four patients completed the study. Both sides demonstrated significant reductions of mean RL*I and mean FHSS _m from baseline (P < .01). At the 4th week, the ITR-treated side showed more improvement of mean RL*I than the placebo-treated side (62.5% vs 47.3% improvement, P < .05). The mean FHSS _m on the ITR-treated was reduced at a significantly higher percentage than the placebo-treated side (54.4% vs 40.2% reduction, P < .05). Partial recurrence was observed on both sides. No serious side effects were noted.
Conclusion: Combined ITR and LFQS therapy was more superior than LFQS monotherapy in the treatment of facial hyperpigmentation. ITR may serve as adjuvant for patients with such condition.
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