Tretinoin is derived from retinoic acid, which is the acid form of vitamin A. Vitamin A had traditionally been known as an acne reducer, but if it's taken in large-enough quantities, it's toxic. In the early 1980s, Swiss pharmaceutical company Hoffmann-La Roche developed synthetic tretinoin as an anti-acne medication [source: IBIS]. It's taken in pill form and is commonly known under the brand name Accutane (in a form called isotretinoin). It's effective as an anti-acne drug. Researchers are not really sure what makes tretinoin reduce acne -- they're pretty sure it slows the production of skin oils, but they're not sure how.
The most basic side effect is an increase in skin problems in the short term. Users may suffer worse acne, red skin with scaling or flaking, sensitive skin, dry skin or sensitivity to the sun. After a week or more, these symptoms fade and an overall improvement will be seen.
The most severe confirmed side effect occurs only when the drug is taken by pregnant women, or a woman becomes pregnant while taking it. Most of the time, this results in a miscarriage. If the baby is carried to term, it may be born with severe birth defects. As a result, in the United States, patients must go through a more rigorous process before being approved to take Accutane. Females who are old enough that they could potentially become pregnant must take part in the iPledge program, a system that ensures women exposed to teratogens (drugs or chemicals that cause birth defects) don't become pregnant. Two negative pregnancy tests are required prior to taking isotretinoin, along with monthly pregnancy tests throughout the course of treatment. It's also recommended that women use two concurrent forms of birth control to make sure they don't get pregnant while taking the drug [source: Medicinenet].
Oral tretinoin should be taken with the antibiotic tetracycline. It's OK to take tetracycline while using topical tretinoin (which we'll discuss in detail in the next section). In fact, this combination is often prescribed by dermatologists. There is one other interaction to watch out for, however. Because tretinoin is a form of vitamin A, it can lead to increased levels of vitamin A in the body. Other vitamin A supplements should not be taken while taking tretinoin, because this could lead to toxic levels of vitamin A in the patient's body.
Ironically, pregnant women often take Vitamin A supplements because developing fetuses need a certain level of retinoic acid to develop properly. The body converts the vitamin A partly into retinoic acid -- without it, the fetus could suffer from birth defects.
There are also reports that the use of Accutane leads to depression and suicide, and that it causes Crohn's disease and other inflammatory bowel disorders. However, research into these potential side effects has been inconclusive [source: Barnes]. Due to the potential severity of all these various side effects, tretinoin should only be used as a last resort for severe acne that doesn't respond to milder treatments.
Next, we'll look at the use of tretinoin in a cream or gel form.