fluorouracil topical, Carac, Efudex, Fluoroplex

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GENERIC NAME: fluorouracil, topical

BRAND NAME: Carac, Efudex, Fluoroplex

DRUG CLASS AND MECHANISM: Topical fluorouracil is a drug that is used to treat conditions of the skin in which there is rapid multiplication (division) of cells, for example, skin cancer. In order to multiply or divide, cells must produce DNA for each new cell. The DNA is critical since it is the genetic material that directs the activity of all cells. Production of DNA depends on the production of RNA which serves as a messenger during the production of DNA. Fluorouracil prevents the formation of RNA which, in turn, prevents the formation of DNA. As a result, cells cannot multiply. With continued treatment, the remaining cells also die. The FDA approved fluorouracil in July 1970.



PREPARATIONS: Cream 0.5, 1 and 5%. Solution 2 and 5%.

STORAGE: Cream and solution should be stored at room temperature, between 15-30 C (59-86 F).

PRESCRIBED FOR: Topical fluorouracil is used to treat certain skin conditions in which cells are multiplying rapidly. It is used to treat cancerous or precancerous conditions including solar keratoses, actinic keratosis, superficial basal cell carcinoma, and Bowen's disease (a type of skin cancer). It also is used to treat some noncancerous conditions in which cells are dividing rapidly, including psoriasis, genital warts, and porokeratosis (an unusual inherited skin condition causing dry patches on the arms and legs). Fluorouracil works best on the face and scalp and is less effective on other areas of the body. It also destroys sun-damaged skin cells making the skin smoother and more youthful-appearing.

DOSING: The cream or solution is applied once or twice daily after washing the area that is to be treated with plain water. The course of treatment continues for at least 2-6 weeks depending on the condition being treated. A tiny amount of the cream should be gently rubbed into all of the treated areas with a fingertip. It is important to apply it to all of the skin and not just visible lesions. Afterwards, the finger should be rinsed thoroughly with water. (Alternatively, a glove can be used.) After a few days, the lesion becomes red and may even blister and weep. There may be some soreness. Tretinoin cream enhances the effect of 5-fluorouracil by peeling off the top layer of skin. When fluorouracil is prescribed with tretinoin cream, the combination works best if the tretinoin has been used for at least two weeks prior to starting fluorouracil.

DRUG INTERACTIONS: There are no known drug interactions with topical fluorouracil.

PREGNANCY: Although very little fluorouracil is absorbed from normal skin, about 20% can be absorbed into the blood when fluorouracil is applied to damaged skin. Fluorouracil can cause damage to the fetus, and it should not be used by pregnant women.

NURSING MOTHERS: It is not known whether fluorouracil passes into breast milk. Since some amount is absorbed from the skin into the body nursing mothers should not use fluorouracil.

SIDE EFFECTS: With application of fluorouracil, initially there usually is a mild to severe stinging or burning sensation or irritation. It also sensitizes the skin to sun and promotes sunburn. After five to ten days of treatment, the sun-damaged parts of treated skin can become red and irritated. If exposure to sun is unavoidable, sunscreen with SPF of 15 or greater should be used, especially during summer months and mid-day. Fluorouracil also may cause prolonged hypo-pigmentation (lightening of the skin), which is more noticeable in dark-skinned persons. Such individuals may wish to first test fluorouracil in a cosmetically unimportant areas. Certain areas are more sensitive to severe irritation, including skin folds, the lips, and the eyelids. Make-up may increase the irritation. Occasionally, excessive inflammation may result in ulcer formation, persistent white marks or scarring, and secondary bacterial infections may occur.

Reference: FDA Prescribing Information

Last Editorial Review: 2/6/2012

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