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Topical Retinoids
Retinoids are chemicals derived from vitamin A (retinol). Topical retinoids were first used in patients suffering from acne. Today topical retinoids play a key role in the treatment of acne, repairing sun damage, and reducing wrinkles. In addition to the FDA-approved indications, topical retinoids have numerous off-label benefits in various dermatologic disorders. Topical retinoids come in cream, gel, and liquid forms. Tretinoin (retinoic acid) is the best-known topical retinoid. It is available under the trade names Retin-A, Avita, and Renova. It is available as a cream (0.025%, 0.05%, and 0.1%), gel (0.01% and 0.025%), and a liquid (0.05%). In tretinoin microsphere (Retin-A Micro), tretinoin is encapsulated in a polymer that slowly releases the active ingredient, resulting in less irritation than with other preparations. Adapalene (Differin) is the mildest topical retinoid with direct anti-inflammatory properties. It is available as a gel or cream at 0.1% strength. Major advantage is that it causes less skin irritation than tretinoin and usually better tolerated. Adapalene treats acne as well as tretinoin. Tazarotene (Tazorac) is a potent third-generation topical retinoid. It is available in 0.05% and 0.1% gel and cream formulations. While tazarotene generally is considered to be the most effective topical retinoid for acne2, it is also more irritating than tretinoin or adapalene. Tazarotene is a pregnancy category X agent. It is more expensive than the other retinoids. Acne vulgaris is an extremely common, chronic, and recurring skin disease. Acne is characterized by pimples, blackheads, and red, swollen bumps on the skin (usually the face, neck, shoulders, or back). The term acne is used to describe the condition when a person has between 5 to 10 pimples, blackheads, or red and swollen bumps on the body at the same time. Topical retinoids (tretinoin, adapalene, and tazarotene) are effective treatments for mild to moderately severe acne, including inflammatory lesions. They can be used as a first-line agent for all types of acne lesions. Overall, retinoids reduce acne lesions by 40-70%. With all retinoids, visible improvement occurs after 8 to 12 weeks of treatment. Retinoids have comedolytic and anti-inflammatory properties. They work by increasing skin cell turnover promoting the extrusion of the plugged material and unblock pores. Retinoids also shrink oil glands, resulting in reduced pore size. According to the clinical trials, 0.1% adapalene gel is as effective as 0.025% tretinoin gel. Adapalene is superior to 0.025% tretinoin gel in both tolerability and speed of efficacy, and is equally effective to 0.1% tretinoin microsphere. Sunlight is a major cause of the skin changes we think of as aging changes such as wrinkles, dryness, and age spots. Retinoids are very potent remedies for treating the signs of aging and photodamaged skin. They exfoliate and renew the skin. If used long term, retinoids reduce fine wrinkles, freckles, roughness and improve general skin appearance. However, cessation of tretinoin therapy for 6 months results in some reversal of the beneficial effects seen after treatment. Retinoids work by increasing the natural turnover rate of the skin. They also prevent collagen loss and stimulate formation of new collagen and hyaluronic acid within the dermis. These effects promote skin texture improvement and fine wrinkles reduction. Melasma is a brown or grayish-brown hyperpigmentation of skin predominantly affecting the faces of women. Topical tretinoin produces significant improvement of melasma, mainly due to reduction in epidermal pigment 1. The treatment of hyperpigmentation disorders is usually a long process. Although tretinoin can be effective as monotherapy for melasma, it requires 20 to 40-week treatment to see noticeable improvement. References
Last updated: April, 2013 |