Phtoruracil - General Information
A pyrimidine analog that is an antineoplastic antimetabolite. It interferes with DNA synthesis by blocking the thymidylate synthetase conversion of deoxyuridylic acid to thymidylic acid. [PubChem]
Pharmacology of Phtoruracil
Phtoruracil is an antineoplastic anti-metabolite. Anti-metabolites masquerade as purine or pyrimidine - which become the building blocks of DNA. They prevent these substances becoming incorporated in to DNA during the "S" phase (of the cell cycle), stopping normal development and division. Phtoruracil blocks an enzyme which converts the cytosine nucleotide into the deoxy derivative. In addition, DNA synthesis is further inhibited because Phtoruracil blocks the incorporation of the thymidine nucleotide into the DNA strand.
Phtoruracil for patients
Carac Cream, 0.5% (fluorouracil cream)
Read this leaflet carefully before you start to use your medicine. Read the information you get every time you get more medicine. There may be new information about the drug. This leaflet does not take the place of talks with your doctor. If you have any questions or are not sure about something, ask your doctor or pharmacist.
What is Carac?
Carac (Care ack) is a cream used by adults to treat skin conditions on the face and front part of the scalp called solar keratosis or actinic keratosis.
Who should not use Carac?
Do not use Carac
· if you are pregnant or might become pregnant. Carac may harm your unborn child.
·if you are nursing a baby. We do not know if Carac can pass to the baby through the milk.
·if you have dihydropyrimidine dehydrogenase (DPD) enzyme deficiency. The active ingredient in Carac, fluorouracil, can cause serious side effects in patients who are DPD enzyme deficient. If you have DPD enzyme deficiency and use medications containing fluorouracil, you may develop serious side effects such as stomach pain, bloody diarrhea, vomiting, fever, or chills.
· if you are allergic to the ingredients in Carac. Ask your doctor or pharmacist about the inactive ingredients.
· if under 18 years of age. Carac should not be used in children. Tell your doctor if you are able to become pregnant. Your doctor may advise you about birth control to avoid pregnancy.
How should I use Carac?
Use Carac once a day as instructed by your doctor. Use it only on your skin. You should use Carac for up to 4 weeks.
1. Clean the area where you will apply Carac. Rinse well and dry the area with a towel and wait 10 minutes before applying Carac.
2. Put Carac on your face as directed by your physician, using your fingertips. Use enough to cover the affected skin.
3. Avoid contact with your eyes, nostrils, and mouth.
4. Wash your hands as soon as you finish putting the Carac on your skin.
5. A moisturizer/sunscreen may be applied 2 hours after Carac has been applied. Do not use any other skin products including creams, lotions, medications or cosmetics ñunless instructed by your doctor.
What should I avoid while using Carac?
Avoid sunlight or other ultraviolet light (such as tanning booths) as much as possible while using Carac. Sunlight may increase your side effects. When exposed to sunlight, wear a hat and use sunscreen.
Do not cover the treated skin with a dressing.
Do not breast feed or become pregnant while using Carac. If you do become pregnant, stop using Carac and tell your doctor right away.
What are the possible side effects of Carac?
Most patients using Carac get skin reactions where the medicine is used. These reactions include redness, dryness, burning, pain, erosion (loss of the upper layer of skin), and swelling. Irritation may continue for two or more weeks after treatment is over. The treated area may become unsightly during therapy.
Some patients get eye irritation. Eye irritation might consist of burning, sensitivity, itching, stinging, and watering. If you are concerned about side effects, talk to your doctor.
A few patients have reported side effects such as stomach pain, diarrhea, vomiting, fever, or chill, possibly due to the lack of a specific enzyme, DPD, in their body. If you experience any of these symptoms, discontinue therapy immediately, and contact your doctor.
Keep this medicine at room temperature (68-77 F/ 20-25 C). Throw away unused medicine. Keep this medicine out of the reach of children.
General advice about prescription medicines
Medicines are sometimes prescribed for conditions that are not described in patient information leaflets. Do not use it for a condition for which it was not prescribed. This medicine is for your use only. Never give it to other people. It may harm them even if their skin problem appears to be the same as yours. Do not use Carac after the expiration date on the tube.
No information available.
Fluorouracil may cause fetal harm when administered to a pregnant woman. Fluorouracil is contraindicated in women who are or may become pregnant. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus.
No adequate and well-controlled studies have been conducted in pregnant women with either topical or parenteral forms of fluorouracil. One birth defect (ventricular septal defect) and cases of miscarriage have been reported when fluorouracil was applied to mucous membrane areas. Multiple birth defects have been reported in the fetus of a patient treated with intravenous fluorouracil.
Animal reproduction studies have not been conducted with Carac. Fluorouracil, the active ingredient, has been shown to be teratogenic in mice, rats, and hamsters when administered parenterally at doses greater than or equal to 10, 15 and 33 mg/kg/day, respectively, [4X, 11X and 20X, respectively, the Maximum Recommended Human Dose (MRHD) based on body surface area (BSA)]. Fluorouracil was administered during the period of organogenesis for each species. Embryolethal effects occurred in monkeys at parenteral doses greater than 40 mg/kg/day (65X the MRHD based on BSA) administered during the period of organogenesis.
Carac should not be used in patients with dihydropyrimidine dehydrogenase (DPD) enzyme deficiency. A large percentage of fluorouracil is catabolized by the enzyme dihydropyrimidine dehydrogenase (DPD). DPD enzyme deficiency can result in shunting of fluorouracil to the anabolic pathway, leading to cytotoxic activity and potential toxicities.
Carac is contraindicated in patients with known hypersensitivity to any of its components.
Additional information about Phtoruracil
Phtoruracil Indication: For the topical treatment of multiple actinic or solar keratoses. In the 5% strength it is also useful in the treatment of superficial basal cell carcinomas when conventional methods are impractical, such as with multiple lesions or difficult treatment sites. Phtoruracil injection is indicated in the palliative management of some types of cancer, including colon, rectum, breast, stomach and pancrease.
Mechanism Of Action: Phtoruracil inhibits thymidylate synthetase, leading to inhibition of DNA and RNA synthesis and cell death.
Drug Interactions: Anisindione The antineoplasic agent increases the anticoagulant effect
Dicumarol The antineoplasic agent increases the anticoagulant effect
Acenocoumarol The antineoplasic agent increases the anticoagulant effect
Warfarin The antineoplasic agent increases the anticoagulant effect
Ethotoin Phtoruracil increases the effect of hydantoin
Fosphenytoin Phtoruracil increases the effect of hydantoin
Mephenytoin Phtoruracil increases the effect of hydantoin
Phenytoin Phtoruracil increases the effect of hydantoin
Metronidazole Risk of 5-FU toxicity when associated with metronidazole
Cimetidine Cimetidine increases the effect and toxicity of fluorouracil
Food Interactions: Vitamin B1 needs increased with long term use.
Generic Name: Fluorouracil
Synonyms: Not Available
Drug Category: Immunosuppressive Agents; Antimetabolites; Antineoplastic Agents
Drug Type: Small Molecule; Approved
Other Brand Names containing Fluorouracil: 5 Fluorouracil; Adrucil; Arumel; Carac; Carzonal; Effluderm; Efudex; Efudix; Efurix; FU; Fluoroblastin; Fluoroplex; Fluracil; Fluracilum; Fluri; Fluril; Fluro Uracil; Ftoruracil; Kecimeton; Phthoruracil; Phtoruracil; Queroplex; Timazin; URF; Ulup;
Toxicity (Overdose): LD50=230mg/kg (orally in mice)
Protein Binding: 8-12%
Half Life: 10-20 minutes
Dosage Forms of Phtoruracil: Solution Intravenous
Chemical IUPAC Name: 5-fluoro-1H-pyrimidine-2,4-dione
Chemical Formula: C4H3FN2O2
Fluorouracil on Wikipedia: https://en.wikipedia.org/wiki/Fluorouracil
Organisms Affected: Humans and other mammals