FLUOROPLEX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FLUOROPLEX (FLUOROPLEX).
Fluorouracil is a fluorinated pyrimidine antimetabolite that inhibits thymidylate synthase, thereby interfering with DNA synthesis. It is also incorporated into RNA, disrupting RNA processing and function.
| Metabolism | Primarily metabolized via dihydropyrimidine dehydrogenase (DPD) in the liver; also undergoes catabolism to urea and other inactive metabolites. |
| Excretion | Renal excretion of unchanged drug and metabolites accounts for approximately 85-90% of elimination; biliary/fecal excretion is minimal (<5%). |
| Half-life | Terminal elimination half-life is 0.5-2 hours, reflecting rapid clearance; clinically, this supports continuous infusion or frequent dosing for sustained antitumor effect. |
| Protein binding | Approximately 10% bound to plasma proteins (primarily albumin). |
| Volume of Distribution | 0.3-0.5 L/kg, indicating distribution into total body water with limited tissue binding. |
| Bioavailability | Topical: 1-5% systemic absorption; intravenous: 100%. |
| Onset of Action | Topical: 2-4 weeks for visible clinical response; intravenous: immediate cellular uptake with effects within 24-48 hours. |
| Duration of Action | Topical: Effect persists for weeks after discontinuation due to tissue binding; intravenous: effects last 1-2 weeks post-infusion. |
Topical: Apply thin layer to lesion twice daily (morning and evening) for 2-4 weeks. Maximum treated area: 500 cm² per session.
| Dosage form | CREAM |
| Renal impairment | No adjustment required for topical use. Systemic absorption is minimal, but consider cautious use in severe renal impairment (eGFR <30 mL/min/1.73 m²) due to potential accumulation of metabolites. |
| Liver impairment | No adjustment required for topical use. For systemic formulations (not typical), avoid in Child-Pugh C due to risk of toxicity; no data for Child-Pugh A/B. |
| Pediatric use | Safety and efficacy not established for pediatric patients under 12 years. For older children, follow adult topical dosing with caution under specialist supervision. |
| Geriatric use | No specific dose adjustment required for topical use; however, skin integrity and absorption may be altered. Use the lowest effective dose and limit treatment area due to increased risk of adverse effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for FLUOROPLEX (FLUOROPLEX).
| Breastfeeding | Fluorouracil is excreted into human milk; M/P ratio not available. Due to potential for serious adverse effects in the nursing infant, including immunosuppression and carcinogenesis, breastfeeding is not recommended during treatment and for at least several weeks after the last dose. |
| Teratogenic Risk | Fluorouracil is contraindicated in pregnancy. First trimester: High risk of congenital malformations, including craniofacial defects, cardiac anomalies, and CNS abnormalities based on animal studies and limited human data. Second and third trimesters: Risk of fetal growth restriction, neonatal myelosuppression, and potential for spontaneous abortion. Use only if clearly needed and no alternative available. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to fluorouracil or any component of the formulation; patients with dihydropyrimidine dehydrogenase (DPD) deficiency.
| Precautions | Avoid contact with eyes, mucous membranes, and broken skin. May cause local inflammatory reactions, photosensitivity, and allergic contact dermatitis. Discontinue if severe irritation occurs. |
| Food/Dietary | No known significant food interactions. Usually no dietary restrictions. |
| Clinical Pearls |
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| Fetal Monitoring | Monitor complete blood count (CBC) with differential, liver function tests, renal function, and electrolytes regularly. Assess for signs of infection, bleeding, and stomatitis. Fetal ultrasound for growth and anatomy if exposure occurs. Monitor for maternal hepatotoxicity and cardiomyopathy. |
| Fertility Effects | Fluorouracil may cause gonadal suppression, potentially leading to amenorrhea in women and oligospermia in men. These effects may be reversible after treatment discontinuation, but permanent infertility has been reported, especially with high cumulative doses. |
| FLUOROPLEX (fluorouracil cream) is a topical antineoplastic indicated for actinic keratosis. Apply thinly to lesions; avoid healthy skin. Use occlusive dressing may increase penetration. Maximum area treated should not exceed 500 cm². Discontinue if severe inflammation or allergic reaction occurs. Protect treated area from sunlight. Not for use on mucous membranes or eyes. |
| Patient Advice | Apply the cream exactly as prescribed, usually once or twice daily. · Do not cover the treated area with bandages unless instructed. · Expect redness, scaling, and burning during treatment; this indicates drug action. · Avoid sun exposure and use sunscreen on treated areas. · Wash hands immediately after application. · Do not use on broken or irritated skin. · Contact healthcare provider if severe pain or blistering occurs. |