Tretinoin is used topically for the treatment of acne vulgaris, principally grades I-III, in which comedones, papules, and pustules predominate. Tretinoin therapy is not curative and relapses generally occur within 3-6 weeks after the drug is discontinued. Best results are usually obtained in the treatment of early stages of acne vulgaris in which numerous comedones are present. The drug is not effective for the treatment of most cases of severe pustular and deep nodulocystic acne; however, it has been suggested that it may be used adjunctively in the management of associated comedones.
Tretinoin is used topically as a 0.05 or 0.1% cream for palliative therapy to improve dermatologic changes (e.g., fine wrinkling, mottled hyperpigmentation, roughness) associated with photodamage. Clinical studies to date indicate that therapy with the drug may at least partially reverse photodamaged skin clinically and histologically. However, many patients can achieve desired palliative effects on certain photoaging-associated dermatologic changes without tretinoin by employing a comprehensive skin care plan, emollient creams, and a sun avoidance program that includes the use of effective sunscreens (minimum strength of SPF 15) and protective clothing. Therefore, topical tretinoin therapy should be used under medical supervision as an adjunct to a comprehensive skin care plan and sun avoidance program and should be reserved for patients who do not achieve the desired effects with such programs alone (i.e., without tretinoin). Patients should be advised that topical therapy with tretinoin does not eliminate wrinkles, repair photodamaged skin, reverse photoaging, or restore a more youthful or younger dermal histologic pattern, and that most of the mitigating effects of tretinoin on fine wrinkles, mottled hyperpigmentation, and tactile roughness of skin will be lost in the majority of patients once such combined, comprehensive therapy is discontinued. The manufacturer states that safety and efficacy of topical tretinoin therapy for photoaging beyond 48 weeks have not been established.
Short-term (16-24 weeks) controlled studies in patients with mild to moderate photodamaged skin have shown that topical tretinoin 0.05 or 0.1% cream may reduce fine wrinkling and increase skin pinkness and, to a lesser degree, reduce coarse wrinkling and tactile roughness of the skin on the forearm and face of patients with photodamaged skin. However, after such improvement, deep coarse wrinkles and telangiectasis still will be evident, at least with short-term (4-6 months) therapy. Similar findings of improved skin appearance, including improvements in fine wrinkles, mottled hyperpigmentation, and roughness, have been noted in several other placebo-controlled studies in patients with mild to moderately severe photodamaged skin receiving topical tretinoin (0.05 or 0.1%) cream therapy for up to 12 months. In 2 studies employing a 0.05% tretinoin cream to the face, moderate improvements in these respective findings (manifested as a 2-point reduction in a 10-point scale of photodamage severity) were observed in 24, 38, and 16% of patients at 24 weeks; minimal improvements (manifested as a 1-point reduction in severity) were observed in 27-40% of patients and no improvement was observed in 35-49% of patients. Most patients also were instructed to avoid sun exposure and to use an effective sunscreen. Lentigines (hyperpigmented macules, liver spots) and solar-induced freckling also may show improvement (e.g., lightening or disappearance); in one study employing tretinoin 0.1% cream for 10 months, hyperpigmented areas did not return during a 6-month follow-up after discontinuance of the drug, and further improvement was observed in most other patients who continued tretinoin beyond 10 months. Some clinical improvement occasionally may be evident within 2 weeks of initiating therapy, consisting mainly of an increase in tightness and pinkness of the skin; clinically important changes in wrinkles usually are evident within 8 weeks.
Although the manufacturer states that safety and efficacy of topical tretinoin have not been established in patients with actinic keratoses, there is limited evidence that the drug also can reduce or eradicate microscopic actinic keratoses and improve clinically recognizable lesions in some patients with this condition. However, macular, erythematous flare-ups of actinic keratoses may occur for several months prior to resolution or reduction in size. The manufacturer also states that safety and efficacy of topical tretinoin therapy have not been established for dermatologic neoplasms, nor have they been established for patients with moderately or heavily pigmented skin.
The most frequent adverse effect associated with tretinoin therapy for photoaging is dermatitis, which occurs in almost all patients, is characterized by erythema, localized swelling, xerosis, and mild scaling, and often requires withholding one or more applications of the drug. Changes in the skin induced by the drug (e.g., thinned horny layer, amplified vasculature) also may result in increased reactivity to environmental (e.g., photosensitivity, wind and cold exposure) and other stimuli (e.g., excessive heat, diaphoresis, increased skin contact with jewelry, concomitant use of irritating cosmetics or facial saunas); in addition, patients may be more susceptible to the development of a sunburn within the first few months of topical tretinoin therapy.
Other Topical Uses
Tretinoin has been used topically for the treatment of flat warts. The drug also has been used with topical fluorouracil for the temporary, initial combination therapy of multiple actinic (solar) keratoses on areas other than the head and neck (e.g., hands, arms). In concentrations of 0.1-0.3%, tretinoin has been used topically for the treatment of other skin conditions such as psoriasis, ichthyosis congenita, icthyosis vulgaris, lamellar icthyosis, keratosis palmaris et plantaris, epidermolytic hyperkeratosis, senile comedones, senile keratosis, keratosis follicularis (Darier's disease), and basal cell carcinomas. However, use of topical tretinoin in these conditions remains investigational.
For systemic uses of tretinoin (e.g., cancer), see Tretinoin 10:00.