What is tretinoin (Retn-A)? How does it work (mechanism of action)?
Tretinoin is a derivative of vitamin A. It is used on the skin (topically) in the treatment of mild to moderate acne and on skin that has been damaged by excessive exposure to the sun. Tretinoin irritates the skin and causes the cells of the skin to grow (divide) and die more rapidly, increasing the turnover of cells. The number of layers of cells in the skin actually is reduced. In patients with acne, new cells replace the cells of existing pimples, and the rapid turnover of cells prevents new pimples from forming. By a similar mechanism, tretinoin can reduce some wrinkles, areas of darkened skin (hyperpigmentation), and rough areas of skin, all of which occur in sun-damaged skin.
In patients with sun-damaged skin, improvements in the skin usually are seen within the first 3 to 4 weeks of treatment. Brown spots begin to fade after six to eight weeks. Wrinkles decrease or disappear after three to six months. Following application to the skin, a minimal amount of drug is absorbed into the body.
The FDA approved topical tretinoin in 1971.
What are the uses for tretinoin?
Topical tretinoin is used for the treatment of:
What are the side effects of tretinoin?
Following the application of tretinoin to the skin, there often is local inflammation. This reaction disappears when treatment is stopped. Mild stinging or a sensation of warmth also can occur when applying tretinoin.
The common side effects of tretinoin are:
- Excessive dryness
Other side effects of tretinoin include:
- Increased sun sensitivity
- Darkening or lightening of the skin
- Initial acne flare-up
Acne is the result of an allergy.
What is the dosage for tretinoin?
Before applying topical tretinoin, the affected area of the skin should be cleansed with soap and dried. Patients should then wait 20 to 30 minutes before applying tretinoin, gently rubbing it into the affected area. The hands should be washed immediately after application. Tretinoin usually is applied once daily, in the evening.
Which drugs or supplements interact with tretinoin?
Combining other topical acne medications (for example, salicylic acid) with tretinoin may lead to excessive skin irritation. Use of abrasive soaps or cleansers, astringents, skin waxes and other products that irritate the skin may add to tretinoin-induced skin irritation. Medications [for example, tetracycline (Achromycin)] that cause sun sensitivity should not be combined with tretinoin because of additive sun sensitivity.
Is tretinoin safe to take if I’m pregnant or breastfeeding?
There are no adequate studies of topical tretinoin use during pregnancy. Physicians must weigh the potential risks and benefits before prescribing tretinoin during pregnancy.
It is unknown whether tretinoin is secreted into breast milk. It also is unknown if topically applied tretinoin accumulates to an extent sufficient to be of concern in the infant. Nonetheless, since oral tretinoin is not recommended during lactation, it probably is prudent to avoid nursing during treatment with topical tretinoin.
What else should I know about tretinoin?
- The brand names available in the US for tretinoin are Retin-A, Retin-A Micro, Atralin, Renova, and Avita.
- Tretinoin is available as a:
- Gel: 0.01%, 0.025%, 0.04%, 0.05%, 0.1%.
- Cream: 0.02%, 0.025%, 0.0375%, 0.05%, and 0.1%.
- Solution: 0.05%.
- Capsule: 10 mg.
- Tretinoin should be store at room temperature, between 15 C – 25 C (59 F – 77 F).
- Tretinoin is available in generic form. You need a prescription from your doctor for this medication.