Fluorouracil

Selected IV label treats adenocarcinoma of colon/rectum, breast, stomach and pancreas. Tumor type, protocol, response and patient risks determine treatment; no guideline-preferred regimen, stage-specific choice or unreviewed off-label tumor indication asserted.

Efudex: multiple actinic/solar keratoses; ONLY 5% also superficial basal-cell carcinoma when conventional treatment is impractical, with diagnosis confirmed. It is not established for other BCC types.0.5% selected cream: multiple actinic/solar keratoses of face/anterior scalp, adults. Tolak 4%: actinic keratoses face/ears/scalp; pediatric use not intended. No universal BCC indication across strengths.

Test DPYD before initiation unless immediate treatment necessary. Avoid complete DPD deficiency; partial deficiency requires individualized dosing/tolerability/intention review, no fixed reduction supplied. Withhold for cardiotoxicity, hyperammonemic/neurologic toxicity, grade 3–4 diarrhea/mucositis, grade 2–3 hand-foot syndrome or grade 4 myelosuppression. For diarrhea/mucositis/myelosuppression/hand-foot toxicity, resume at reduced dose after resolution or improvement to grade 1. No recommended restart dose after cardiac, hyperammonemic or specified neurologic toxicity. Clinical team controls grading/rechallenge.

IV specialist aseptic cytotoxic preparation, central venous line/pump for continuous infusion; no simultaneous other drugs in same IV line. Selected syringe/diluted solution storage≤4 hours at 25°C before administration; discard unused single-dose vial. Topicals are skin-only, not swallowed, injected, ophthalmic or intravaginal; avoid airtight dressings and inadvertent transfer. No interchangeable frequency by percentage or independent regimen conversion.

Selected IV section 4 lists none, while boxed warning/2.1/5.1 directs avoidance with complete DPD deficiency; do not mistake “none” for permission in this high-risk group. Efudex/0.5% contraindicate pregnancy or potential pregnancy during therapy and ingredient hypersensitivity, and state not to use with DPD deficiency. Tolak formal contraindications are pregnancy and DPD deficiency; peanut/other allergy is a stop/avoid-review warning, not an invented additional section 4 item.

Current selected IV box: serious adverse reactions/death in complete DPD deficiency, test DPYD before therapy unless immediate treatment necessary, avoid specified homozygous/compound heterozygous variants producing complete deficiency. No proven safe dose. Selected topical labels have no boxed warning; their DPD/pregnancy restrictions still apply.

IV severe marrow/GI/cardiac/neurotoxicity, hand-foot syndrome, nausea/vomiting, skin/nail/ocular effects and allergy are reported. Topicals commonly cause local irritation and occasional eye reaction/allergy; severe systemic toxicity is possible in susceptible patients. IV overdose or early unusually severe systemic toxicity is an emergency: current IV label specifies uridine triacetate within 96 hours after infusion ends; Vistogard supports overdose regardless of symptoms or defined early severe toxicity, start promptly within 96 hours. Later-start effectiveness unestablished, not a reason to delay emergency review. No home vomiting/lavage or animalLD 50 safety extrapolation.

Clinically important INR/prothrombin-time rises with warfarin/coumarin anticoagulants: monitor closely and adjust anticoagulant through treating team. Selected label suggests possible CYP2C9 inhibition based partly on prodrug context; no universal established numerical interaction magnitude or dose change.

Tolak interaction-specific trials were not designed; steroid/immunomodulator exposure and several local retinoid/steroid/acid/peel products were generally excluded.0.5% Patient Information restricts other skin products unless instructed. Review other topical/systemic therapies. IV combinations shown are specialist protocol examples, not blanket simultaneous-line compatibility or independent dosing permission.

Selected labels provide no validated numerical renal/hepatic/dialysis table; oncology/dermatology team must individualize actual clinical risk. DPD catabolism is distinct from routine creatinine-based adjustment. Hyperammonemic encephalopathy can occur without liver disease. No invented dose reduction, dialysis rescue or activity-score algorithm.

IV pediatric safety/effectiveness unestablished. Efudex children unestablished; 0.5% should not be used below 18; Tolak not intended for children. Elderly IV/selected topical experience does not show overall differences; Tolak requires no age-only dose adjustment, but individual sensitivity remains. No unverified pediatric cancer or skin regimen.

Topical products contraindicate pregnancy; Tolak effective contraception during therapy and 1 month after last dose. Selected IV fetal harm warning: females and males with partners of reproductive potential use effective contraception during and 3 months after cessation; potential impaired fertility from animal evidence. Topical/IV labels advise choosing nursing versus treatment because serious infant risk/milk data uncertainty; 0.5% and Tolak patient leaflets say not to breastfeed during use. Do not apply IV 3-month interval to every topical or invent a universal milk-discard interval.

Active metabolites inhibit thymidylate synthase and incorporate into RNA/DNA, affecting rapidly dividing cells. DPD, encoded by DPYD, catabolizes most systemic fluorouracil; deficient activity can greatly increase toxicity. Variant lists are incomplete and testing varies, so no negative-test clearance guarantee.

After single-agent IV bolus, elimination half-life 8–20 minutes increases with dose; 5–20% parent appears unchanged in urine within 6 hours and most remainder is metabolized primarily in liver. These values are not a continuous-infusion or topical dosing algorithm. Topical studies show low but measurable systemic exposure with vehicle/skin-area/inflammation differences; do not use one absorption percentage for all concentrations or exclude serious DPD-related toxicity.

IV: DPYD testing/risk assessment, CBC before each cycle and weekly for weekly/similar schedules plus as needed; monitor severe GI, neurologic, cardiac and hand-foot symptoms and INR with warfarin. Label counsels daily temperature and immediate fever/infection reporting. Topical: diagnosis, response/local reaction and systemic symptoms; biopsy nonresponding/recurring suspicious lesions and follow superficial BCC as indicated. No universal topical CBC timetable or unverified serum target.

Understand route/product plan and contact treating team early for severe symptoms. Skin may look unsightly during and after treatment; avoid UV/occlusion/eyes/mucosa, wash hands and prevent transfer to others/pets. Keep containers and residue inaccessible. Stop/contact clinician if pregnant or systemic toxicity develops; suspected systemic overdose needs immediate emergency/oncology evaluation for time-critical rescue, not waiting for symptoms or 96 hours to pass.

Strength

50 mg/mL; 500 mg/10 mL single-dose vial, colorless-to-yellow sterile solution.

Selected package

Fresenius Kabi vial NDC 63323-117-43; unit of 10 NDC 63323-117-18.

Route / status

Prescription IV cytotoxic drug; selected single-dose vial not a pharmacy bulk package.

Efudex

5% cream 50 mg/g, 40 g tube NDC 0187-3204-47; topical 2%/5% solutions are weight/weight, 10/25 mL dispensers. Do not infer exact mg/mL from w/w without density.

0.5% cream

5 mg/g with microsphere vehicle; selected 30 g tube NDC 75907-169-11. Not interchangeable with 5% or 4%.

Tolak

4%=40 mg/g, 40 g tube NDC 28105-421-40; contains peanut oil.

Scope

Unverified other IV brands/bulk-vial handling and off-label regimens require exact product/protocol review; no preferred chemotherapy guideline or stock claim.

IV 20–25°C, protect from light in carton, do not freeze; qualified cytotoxic preparation/disposal, discard unused single-dose contents. Efudex 25°C with 15–30°C excursions; 0.5% cream 20–25°C. Tolak 25°C with 15–30°C excursions, do not freeze; exact Patient Information 20–25°C. Respect expiration and prevent child/pet access; no household warming/precipitate-recovery instructions.