Treating melasma, chloasma, and postinflammatory hyperpigmentation
Philippe Deprez, Philippe Deprez in Textbook of Chemical Peels, 2016
The histological features of melasma and chloasma are discussed elsewhere in this book. The standard recommendations for treatment often mention only the topical applications tretinoin, hydroquinone, fluorinated corticosteroids, sun protection, and tyrosinase inhibitors; chemical peels are considered as a last resort because of their potential to turn melasma into postinflammatory hyperpigmentation (PIH). Conventional peels require conscientious prepeel preparation to avoid this danger. Easy TCA (ETCA), in combination with appropriate postpeel care, can be used to treat melasma without the constraints of prepeel preparation (Figures 16.1-16.5). Laser therapy is not recommended for treating melasma because lasers are difficult to use and have been linked to many common side effects. The numerous evolutions and promises of laser therapy have not solved these problems.
Rationale of using hypopigmenting drugs and their clinical application in melasma
Published in Expert Review of Clinical Pharmacology, 2015
Among the pigmentary disorders, melasma is the prototype disorder characterized by hyperpigmentation. Although, conventionally, triple combination creams are used, there is a need for alternatives to hydroquinone as the drug has restrictions on its widespread use. This needs an understanding of the steps involved in the melanogenesis and the drugs that inhibit the key steps. The data on in vitro inhibition need to be then translated into clinical in vivo results, before a rationale compounded fixed drug preparation is marketed that inhibits the major steps in the pigmentation pathway. There is also a need to look for drugs that are superior to hydroquinone, as only then will they have a meaningful clinical utility. For now, a few drugs like deoxyarbutin, ellagic acid, dioic acid, n-butylresorcinol and azelaic acid have such properties in clinical trials, while metformin is a recent addition.
Tazarotene versus tazarotene plus hydroquinone in the treatment of photodamaged facial skin: A multicenter, double‐blind, randomized study
Published in Journal of Cosmetic and Laser Therapy, 2006
Nicholas Lowe, Stephen Horwitz, Emil Tanghetti, Zoë Draelos, Alan Menter
Objectives: To compare the efficacy and tolerability of tazarotene plus hydroquinone versus tazarotene alone in the treatment of facial photodamage. Methods: Patients with facial mottled hyperpigmentation of at least moderate severity and an overall integrated assessment of photodamage score of at least moderate applied tazarotene 0.1% cream each evening and either hydroquinone 4% cream or placebo cream each morning for up to 24 weeks. Results: Among 131 patients enrolled, 114/124 (92%) with exit data completed. Both regimens were highly effective in reducing photodamage, with tazarotene plus hydroquinone showing superiority over tazarotene alone for some efficacy measures. The incidence of ⩾1‐grade improvement from baseline (on a scale of none, minimal, mild, moderate, or severe) was significantly greater with tazarotene plus hydroquinone than with tazarotene alone for lentigines (weeks 12–24, p⩽0.01) and mottled hyperpigmentation (week 16, p⩽0.05). The incidence of ⩾50% global improvement was also significantly superior with the combination regimen as early as week 8 (p⩽0.01). Both regimens were associated with good tolerability and high patient satisfaction (no significant between‐group differences). Conclusions: The adjunctive use of hydroquinone can enhance the efficacy of tazarotene in reducing dyspigmentation associated with photodamage.
The impact of hydroquinone on acetylcholine esterase and certain human carbonic anhydrase isoenzymes (hCA I, II, IX, and XII)
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2015
Andrea Scozzafava, Pınar Kalın, Claudiu T. Supuran, İlhami Gülçin, Saleh H. Alwasel
Carbonic anhydrases (CAs) are widespread and the most studied members of a great family of metalloenzymes in higher vertebrates including humans. CAs were investigated for their inhibition of all of the catalytically active mammalian isozymes of the Zn2+-containing CA, (CA, EC 4.2.1.1). On the other hand, acetylcholinesterase (AChE. EC 3.1.1.7), a serine protease, is responsible for ACh hydrolysis and plays a fundamental role in impulse transmission by terminating the action of the neurotransmitter ACh at the cholinergic synapses and neuromuscular junction. In the present study, the inhibition effect of the hydroquinone (benzene-1,4-diol) on AChE activity was evaluated and effectively inhibited AChE with Ki of 1.22 nM. Also, hydroquinone strongly inhibited some human cytosolic CA isoenzymes (hCA I and II) and tumour-associated transmembrane isoforms (hCA IX, and XII), with Kis in the range between micromolar (415.81 μM) and nanomolar (706.79 nM). The best inhibition was observed in cytosolic CA II.
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