BRAND NAMES
- International: Avita, Airol, Locacid, Renova, Retacnyl, Retin A, Retin A Micro
- Brazil: Retin A Micro PI
- Lebanon: A-RET Cream - 0.05%, LOCACID Lotion - 0.1%, LOCACID DERMIQUE Cream - 0.05%, RETACNYL Cream - 0.05 %, RETIN-A Cream - 0.05%, RETIN-A Gel - 0.025%, TRETINOIN Solution - 0.025%, TRETINOIN Solution - 0.05%, TRETINOIN Solution - 0.1%
 MECHANISM OF ACTION
Tretinoin is a first generation topical retinoid. It is the carboxylic acid form of vitamin A.
Tretinoin binds to intracellular receptors in the cytosol and nucleus.
Although tretinoin activates three members of the retinoid acid (RAR) nuclear receptors (RARα, RARβ, and RARγ) which may act to modify gene expression, subsequent protein synthesis, and epithelial cell growth and differentiation, it has not been established whether the clinical effects of tretinoin are mediated through activation of retinoic acid receptors, other mechanisms, or both.
Current evidence suggests that the effectiveness of tretinoin in acne is due primarily to its ability to modify abnormal follicular keratinization. Comedones form in follicles with an excess of keratinized epithelial cells. Tretinoin promotes detachment of cornified cells and the enhanced shedding of corneocytes from the follicle. By increasing the mitotic activity of follicular epithelia, tretinoin also increases the turnover rate of thin, loosely-adherent corneocytes. Through these actions, the comedo contents are extruded and the formation of the microcomedo, the pre-cursor lesion of acne vulgaris, is reduced.
Additionally, tretinoin acts by modulating the proliferation and differentiation of epidermal cells. These effects are mediated by tretinoin’s interaction with a family of nuclear retinoic receptors. Activation of these nuclear receptors causes changes in gene expression. The exact mechanisms whereby tretinoin-induced changes in gene expression regulate skin function are not understood.
- Topical tretinoin is indicated for the treatment of acne vulgaris
- Topical tretinoin is also used to slow skin aging or remove wrinkles. It is a component of many commercial products that are advertised for this purpose.
In general, apply once per day preferably in the evening half an hour before bedtime on perfectly dry skin (fifteen minutes after gentle cleansing with cleansing milk or dermatological soap). Spread a pea-sized quantity of cream or lotion on the lesions.
Therapeutic results should be noticed after two to three weeks. Results may not be optimal until after six weeks of therapy. Once the acne lesions have responded satisfactorily, it may be possible to maintain the improvement with less frequent applications.
Hypersensitivity to tretinoin
 WARNINGS AND PRECAUTIONS
- During the early weeks of therapy, an apparent exacerbation of inflammatory lesions may occur. This is due to the action of the medication on deep, previously unseen lesions and should not be considered a reason to discontinue therapy.
- Avoid the eye, mouth and nose area
- Particular caution should be exercised in using preparations containing peeling agents (such as sulphur, resorcinol, benzoyl peroxide or salicylic acid) with tretinoin.
 PREGNANCY AND LACTATION
- Oral tretinoin has been shown to be teratogenic in a wide variety of animals. Limited animal data urge caution in the use of preparations containing tretinoin during the first trimester of pregnancy. There have been isolated reports of birth defects among babies born to women exposed to topical tretinoin during pregnancy. Topical tretinoin should be used during pregnancy only the potential benefit justifies the potential risk to the foetus.
- It is not known whether tretinoin is excreted in human milk. Since many drugs are excreted in human milk, caution should be exercised when Tretinoin is administered to a nursing mother.
 SIDE EFFECTS
When used, dryness or increased sensitivity to sunlight of the affected skin may occur. Exposure to sunlight, including ultraviolet sunlamps, should be minimised. When exposure to sunlight cannot be avoided, use of sunscreen products and protective clothing over treated areas is recommended
In certain sensitive individuals, Tretinoin induce severe local erythema, persistent dry skin, swelling, rash, pruritus, warmth, burning or stinging, blistering, crusting and/or peeling at the site of application. If the degree of local irritation warrants, the patient should be instructed to either apply the medication less frequently or discontinue its use temporarily.
 RELATED LINKS
|Oral antibiotics||Clindamycin (Oral route) • Doxycycline • Erythromycin (Oral route) • Josamycin • Lymecycline • Minocycline • Tetracycline|
|Topical antibiotics||Clindamycin (Topical) • Erythromycin (Topical)|
|Topical retinoids||Adapalene • Tazarotene • Tretinoin|
|Oral retinoids||Isotretinoin (Oral)|
|Oral contraceptives||Estradiol valerate/Dienogest • Ethinyl Estradiol/Cyproterone acetate|
|Topical Antibacterial/Keratolytic||Benzoyl peroxide • Hydrogen Peroxide Cream|
|Topical combination products||Clindamycin/Benzoyl peroxide • Adapalene/Benzoyl peroxide • Clindamycin/Tretinoin • Miconazole/Benzoyl peroxide • Erythromycin/Benzoyl peroxide • Erythromycin/Isotretinoin|