DESCRIPTION Fluorouracil Cream, USP 5% is a topical preparation containing the fluorinated pyrimidine 5-fluorouracil, an antineoplastic antimetabolite. Fluorouracil Cream contains 5% fluorouracil in a vanishing cream base consisting of white petrolatum, cetyl alcohol, stearyl alcohol, propylene glycol, polysorbate 60, parabens (methyl and propyl), and purified water. Chemically, fluorouracil is 5-fluoro-2,4(1 H ,3 H )-pyrimidinedione. It is a white to practically white crystalline powder which is sparingly soluble in water and slightly soluble in alcohol. One gram of fluorouracil is soluble in 100 mL of propylene glycol. The molecular weight of 5-fluorouracil is 130.08 and the structural formula is: Chemical Structure
⚠️ Warnings
WARNINGS Application to mucous membranes should be avoided due to the possibility of local inflammation and ulceration. Additionally, cases of miscarriage and a birth defect (ventricular septal defect) have been reported when Fluorouracil Cream was applied to mucous membrane areas during pregnancy. Occlusion of the skin with resultant hydration has been shown to increase percutaneous penetration of several topical preparations. If any occlusive dressing is used in treatment of basal cell carcinoma, there may be an increase in the severity of inflammatory reactions in the adjacent normal skin. A porous gauze dressing may be applied for cosmetic reasons without increase in reaction. Exposure to ultraviolet rays should be minimized during and immediately following treatment with Fluorouracil Cream because the intensity of the reaction may be increased. Patients should discontinue therapy with Fluorouracil Cream if symptoms of DPD enzyme deficiency develop (see CONTRAINDICATIONS ). Rarely, life-threatening toxicities such as stomatitis, diarrhea, neutropenia, and neurotoxicity have been reported with intravenous administration of fluorouracil in patients with DPD enzyme deficiency. One case of life-threatening systemic toxicity has been reported with the topical use of Fluorouracil Cream in a patient with DPD enzyme deficiency. Symptoms included severe abdominal pain, bloody diarrhea, vomiting, fever, and chills. Physical examination revealed stomatitis, erythematous skin rash, neutropenia, thrombocytopenia, inflammation of the esophagus, stomach, and small bowel. Although this case was observed with 5% fluorouracil cream, it is unknown whether patients with profound DPD enzyme deficiency would develop systemic toxicity with lower concentrations of topically applied fluorouracil.
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