Depigmenting agents

Topical depigmenting agents (tirosinase inhibitors, antioxidants, peeling agents, melanogenesis inhibitors) [3]... 

Mechanism of Action A depigmenting agent that suppresses melanocyte metabolic processes of the skin. Inhibits the enzymatic oxidation of tyrosine to DOPA (3,4-dihy-droxyphenylalanine). Sun exposure reverses this effect and causes repigmentation. Therapeutic Effect Lightens hyperpigmented areas. 

Depigmenting agent Monobenzone Benoquin Cetyl alcohol NF Sodium lauryl sulfate NF... 

The well-known Kligman s formulas combine the action of tretinoin, a corticosteroid and hydroquinone, but are more irritating than medical cosmetics. The cosmetics used for hyperpigmentation should be applied very soon after the peels (if possible the very next day). If possible they should be applied two or three times a day, before effective sun protection. For more information on topical depigmenting agents, see the section on hyperpigmentation in Chapter 37. 

Topical depigmenting agents cannot be expected to produce rapid results the active products have to penetrate the... 

When a peel causes localized inflammation that visibly develops into hyperpigmentation, even with sun protection and avoidance, a corticosteroid (preferably a fluoro-corticosteroid) should be applied. It should be applied twice a day locally to the erythema before it develops into hyperpigmentation and should not be used long term (1 week at the most), to avoid the side-effects associated with corticosteroids. This treatment should of course be combined with sun protection/avoidance measures and a topical depigmenting agent. 

Solange (a combination of tretinoin and mequinol, a depigmenting agent) Topical Solar (actinic) lentigines... 

Compound 16 showed dose-dependent q totoxicity in a study of inhibition of melanin synthesis by melan-a cell hnes. The cellular survival rate was foimd to be low after treatment with 20 jtM of 16 [45]. Compound 11 inhibited melanin synthesis in the melan-a cells at a concentration of 10 p,M. The inhibition of melanin synthesis by 11 was found to be similar to that of phenylthiourea, which is a well-known melanin synthesis inhibitor [45]. The authors concluded that compound 11 is a new candidate for the development of depigmenting agents [45]. 

A variety of topical depigmenting agents are at hand for the dermatologists to choose from. Setback however is the length of time needed to effect treatment and patient comphance. 

Azelaic acid may be used as a depigmenting agent in those sensitive to hydroquinone at l-2x daily application. 

Jimbow K (1991) N-acetyl-4-S-cystaminylphenol as new type of depigmenting agent for the melanoderma of patients with melasma. Arch Dermatol 127 1528-1534... 

Pineda RT, Chan G, Gabriel T (2006) A randomized double blind placebo controlled comparative study on the safety and efficacy of 0.25% tetrahydrocurcumin (Turmeric) cream as depigmenting agent against 4% hydroquinone cream. RITM, Philippines, unpublished... 

Topical depigmenting agents (hydroquinone, tretinoin, kojic acid, azelaic acid, L-ascorbic acid) are the most commonly used home treatment, but several months are required to see results and very often the pigmentation recms after discontinuation of treatment [4],... 

Topical methimazole is used as a skin depigmenting agent for conditions that include epidermal melasma. In 20 patients who used this treatment once daily for 6 weeks there were no significant changes in circulating thyroid hormone or thyroid-stimulating hormone (TSH) and no significant cutaneous adverse reactions [33 ]. 

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