Medical Editor: John P. Cunha, DO, FACOEP Last updated on RxList: 6/15/2022

Drug Summary

What Is Carac Cream?

Carac Cream, 0.5% (fluorouracil) works by causing the death of cells that grow fastest, such as abnormal skin cells, and is used to treat scaly overgrowths of skin (actinic or solar keratoses). Carac Cream may also be used in the treatment of superficial basal cell carcinoma. Carac Cream is available in generic form.

What Are Side Effects of Carac Cream?

Common side effects of Carac Cream include:

  • skin redness,
  • irritation,
  • dryness,
  • scaling or peeling (exfoliation),
  • burning,
  • rash,
  • pain,
  • swelling, and
  • other local reactions.

Serious side effects of Carac Cream are not likely to occur. Stop using of Carac Cream topical and seek emergency medical attention if you experience an allergic reaction (shortness of breath; closing of your throat; swelling of your lips, face, or tongue; or hives).

Dosage for Carac Cream

Carac Cream should be applied in a once a day dose to the skin where actinic keratosis lesions appear, using enough to cover the entire area with a thin film. Use for up to 4 weeks, as tolerated.

What Drugs, Substances, or Supplements Interact with Carac Cream?

Carac Cream may interact with other prescription or over-the-counter skin products. Tell your doctor all medications and supplements you use.

Carac Cream During Pregnancy and Breastfeeding

Carac Cream topical must not be used if you are pregnant or planning a pregnancy. It is known to harm a fetus. Miscarriage and birth defects have been reported. Discuss birth control with your doctor before starting treatment with Carac. It is unknown if this drug passes into breast milk. Consult your doctor before breastfeeding.

Additional Information

Our Carac Cream, 0.5% (fluorouracil) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

Drug Description



Carac® (fluorouracil cream) Cream, 0.5% , contains fluorouracil for topical dermatologic use. Chemically, fluorouracil is 5-fluoro-2,4(1H, 3H)-pyrimidinedione. The molecular formula is C4H3FN2O2. Fluorouracil has a molecular weight of 130.08.

Carac® (fluorouracil)  Structural Formula Illustration

Carac Cream contains 0.5% fluorouracil, with 0.35% being incorporated into a patented porous microsphere (Microsponge®) composed of methyl methacrylate / glycol dimethacrylate cross polymer and dimethicone. The cream formulation contains the following other inactive ingredients: carbomer 940, dimethicone, glycerin, methyl gluceth-20, methyl methacrylate / glycol dimethacrylate crosspolymer, methylparaben, octyl hydroxy stearate, polyethylene glycol 400, polysorbate 80, propylene glycol, propylparaben, purified water, sorbitan monooleate, stearic acid, and trolamine.

Indications & Dosage


Carac is indicated for the topical treatment of multiple actinic or solar keratoses of the face and anterior scalp.


Carac Cream should be applied once a day to the skin where actinic keratosis lesions appear, using enough to cover the entire area with a thin film. Carac Cream should not be applied near the eyes, nostrils, or mouth. Carac Cream should be applied 10 minutes after thoroughly washing, rinsing, and drying the entire area. Carac Cream may be applied using the fingertips. Immediately after application, the hands should be thoroughly washed. Carac Cream should be applied up to 4 weeks as tolerated. Continued treatment up to 4 weeks results in greater lesion reduction. Local irritation is not markedly increased by extending treatment from 2 to 4 weeks, and is generally resolved within 2 weeks of cessation of treatment.


Storage And Handling

NDC 0187-5200-30    30 g tube

Store at 20° to 25° C (68° to 77° F) [see USP Controlled Room Temperature].

Keep out of reach of children.

Manufactured by: Bausch Health Companies Inc. Laval, Quebec H7L 4A8, Canada. Revised: May 2022.

Side Effects & Drug Interactions


The following were adverse events considered to be drug related and occurring with a frequency of ≥1% with Carac: application site reaction (94.6%), and eye irritation (5.4%). The signs and symptoms of facial irritation (i.e., application site reaction) are presented below.

Summary of Facial Irritation Signs and Symptoms - Pooled Phase 3 Studies

Clinical Sign or Symptom Active
1 Week
2 Week
4 Week
ALL Active
n (%) n (%) n (%) n (%) n (%)
Erythema 76 (89.4) 82 (94.3) 82 (96.5) 240 (93.4) 76 (59.8)
Dryness 59 (69.4) 76 (87.4) 79 (92.9) 214 (83.3) 60 (47.2)
Burning 51 (60.0) 70 (80.5) 71 (83.5) 192 (74.7) 28 (22.0)
Erosion 21 (24.7) 38 (43.7) 54 (63.5) 113 (44.0) 17 (13.4)
Pain 26 (30.6) 34 (39.1) 52 (61.2) 112 (43.6) 7 (5.5)
Edema 12 (14.1) 28 (32.2) 51 (60.0) 91 (35.4) 6 (4.7)

During clinical trials, irritation generally began on Day 4 and persisted for the remainder of treatment. Severity of facial irritation at the last treatment visit was slightly below baseline for the vehicle group, mild to moderate for the 1-week active treatment group, and moderate for the 2- and 4-week active treatment groups. Mean severity declined rapidly for each active group after completion of treatment and was below baseline for each group at the Week 2 post-treatment follow-up visit.

Thirty-one patients (12% of those treated with Carac in the Phase 3 clinical studies) discontinued study treatment early due to facial irritation. Except for three patients, discontinuation of treatment occurred on or after Day 11 of treatment.

Eye irritation adverse events, described as mild to moderate in intensity, were characterized as burning, watering, sensitivity, stinging, and itching. These adverse events occurred across all treatment arms in one of the two Phase 3 studies.

Summary of All Adverse Events Reported in ≥ 1% of Patients in the Combined Active Treatment and Vehicle Groups - Pooled Phase 3 Studies

9721 and 9722 Combined
Adverse Event Active
1 Week
N= 85
2 Week
N= 87
4 Week
N= 85
ALL Active
n (%) n (%) n (%) n (%) n (%)
BODY AS A WHOLE 7 (8.2) 6 (6.9) 12 (14.1) 25 (9.7) 15 (11.8)
  Headache 3 (3.5) 2 (2.3) 3 (3.5) 8 (3.1) 3 (2.4)
  Common Cold 4 (4.7) 0 2 (2.4) 6 (2.3) 3 (2.4)
  Allergy 0 2 (2.3) 1 (1.2) 3 (1.2) 2 (1.6)
  Infection Upper Respiratory 0 0 0 0 2 (1.6)
MUSCULOSKELETAL 1 (1.2) 1 (1.1) 1 (1.2) 3 (1.2) 5 (3.9)
  Muscle Soreness 0 0 0 0 2 (1.6)
RESPIRATORY 5 (5.9) 0 1 (1.2) 6 (2.3) 6 (4.7)
  Sinusitis 4 (4.7) 0 0 4 (1.6) 2 (1.6)
SKIN & APPENDAGES 78 (91.8) 83 (95.4) 82 (96.5) 243 (94.6) 85 (66.9)
  Application Site 78 (91.8) 83 (95.4) 82 (96.5) 243 (94.6) 83 (65.4)
  Reaction Irritation Skin 1 (1.2) 0 2 (2.4) 3 (1.2) 0
SPECIAL SENSES 6 (7.1) 4 (4.6) 6 (7.1) 16 (6.2) 6 (4.7)
  Eye Irritation 5 (5.9) 3 (3.4) 6 (7.1) 14 (5.4) 3 (2.4)

Adverse Experiences Reported By Body System

In the Phase 3 studies, no serious adverse event was considered related to study drug. A total of five patients, three in the active treatment groups and two in the vehicle group, experienced at least one serious adverse event. Three patients died as a result of adverse event(s) considered unrelated to study drug (stomach cancer, myocardial infarction, and cardiac failure).

Post-treatment clinical laboratory tests other than pregnancy tests were not performed during the Phase 3 clinical studies. Clinical laboratory tests were performed during conduct of a Phase 2 study of 104 patients and 21 patients in a Phase 1 study. No abnormal serum chemistry, hematology, or urinalysis results in these studies were considered clinically significant.

To report SUSPECTED ADVERSE REACTIONS, contact Bausch Health US, LLC at 1-800-321- 4576 or FDA at 1-800-FDA-1088 or


No Information Provided



The potential for a delayed hypersensitivity reaction to fluorouracil exists. Patch testing to prove hypersensitivity may be inconclusive.

Patients should discontinue therapy with Carac if symptoms of DPD enzyme deficiency develop.

Rarely, unexpected systemic toxicity (e.g., stomatitis, diarrhea, neutropenia, neurotoxicity) associated with parenteral administration of fluorouracil has been attributed to deficiency of dihydropyrimidine dehydrogenase "DPD" activity. One case of life-threatening systemic toxicity has been reported with the topical use of 5% fluorouracil in a patient with a complete absence of DPD enzyme activity. 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.

Applications to mucous membranes should be avoided due to the possibility of local inflammation and ulceration.




There is a possibility of increased absorption through ulcerated or inflamed skin.

Information For The Patient

Patients using Carac should receive the following information and instructions:

  1. This medication is to be used as directed.
  2. This medication should not be used for any disorder other than that for which it was prescribed.
  3. It is for topical use only.
  4. Avoid contact with the eyes, eyelids, nostrils, and mouth.
  5. Cleanse affected area and wait 10 minutes before applying Carac.
  6. Wash hands immediately after applying Carac.
  7. Avoid prolonged exposure to sunlight or other forms of ultraviolet irradiation during treatment, as the intensity of the reaction may be increased.
  8. 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 at the application site may persist for two or more weeks after therapy is discontinued. Treated areas may be unsightly during and after therapy.
  9. If you develop abdominal pain, bloody diarrhea, vomiting, fever, or chills while on Carac therapy, stop the medication and contact your physician and/or pharmacist.
  10. Report any side effects to the physician and/or pharmacist.
  11. Fluorouracil, including Carac may be fatal if ingested by pets. Avoid allowing pets to contact the Carac container or the skin where Carac has been applied. Store Carac out of reach of pets. Safely discard or clean any cloth or applicator that may retain Carac and avoid leaving any residues of Carac on your hands, clothing, carpeting or furniture.

Laboratory Tests

To rule out the presence of a frank neoplasm, a biopsy may be considered for those areas failing to respond to treatment or recurring after treatment.

Carcinogenesis, Mutagenesis, And Impairment Of Fertility

Adequate long-term studies in animals to evaluate carcinogenic potential have not been conducted with fluorouracil. Studies with the active ingredient of Carac, fluorouracil, have shown positive effects in in vitro and in vivo tests for mutagenicity and on impairment of fertility in in vivo animal studies.

Fluorouracil produced morphological transformation of cells in in vitro cell transformation assays. Morphological transformation was also produced in an in vitro assay by a metabolite of fluorouracil, and the transformed cells produced malignant tumors when injected into immunosuppressed syngeneic mice. Fluorouracil has been shown to exert mutagenic activity in yeast cells, Bacillus subtilis, and Drosophila assays. In addition, fluorouracil has produced chromosome damage at concentrations of 1.0 and 2.0 mcg/mL in an in vitro hamster fibroblast assay, was positive in a microwell mouse lymphoma assay, and was positive in in vivo micronucleus assays in rats and mice following intraperitoneal administration. Some patients receiving cumulative doses of 0.24 to 1.0 g of fluorouracil parenterally have shown an increase in numerical and structural chromosome aberrations in peripheral blood lymphocytes.

Fluorouracil has been shown to impair fertility after parenteral administration in rats. Fluorouracil administered at intraperitoneal doses of 125 and 250 mg/kg has been shown to induce chromosomal aberrations and changes in chromosome organization of spermatogonia in rats. In mice, single-dose intravenous and intraperitoneal injections of fluorouracil have been reported to kill differentiated spermatogonia and spermatocytes at a dose of 500 mg/kg and produce abnormalities in spermatids at 50 mg/kg.

Pediatric Use

Actinic keratosis is not a condition seen within the pediatric population, except in association with rare genetic diseases. Carac should not be used in children. The safety and effectiveness of Carac have not been established in patients less than 18 years old.

Geriatric Use

No significant differences in safety and efficacy measures were demonstrated in patients age 65 and older compared to all other patients.



Nursing Women

It is not known whether fluorouracil is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from fluorouracil, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Overdose & Contraindications


Ordinarily, topical overdosage will not cause acute problems. If Carac is accidentally ingested, induce emesis and gastric lavage. Administer symptomatic and supportive care as needed.

If contact is made with the eye, flush with copious amounts of water.


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 DPD enzyme. 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.

Clinical Pharmacology


There is evidence that the metabolism of fluorouracil in the anabolic pathway blocks the methylation reaction of deoxyuridylic acid to thymidylic acid. In this manner, fluorouracil interferes with the synthesis of deoxyribonucleic acid (DNA) and to a lesser extent inhibits the formation of ribonucleic acid (RNA). Since DNA and RNA are essential for cell division and growth, the effect of fluorouracil may be to create a thymine deficiency that provokes unbalanced growth and death of the cell. The effects of DNA and RNA deprivation are most marked on those cells that grow more rapidly and take up fluorouracil at a more rapid rate. The contribution to efficacy or safety of individual components of the vehicle has not been established.


A multiple-dose, randomized, open-label, parallel study was performed in 21 patients with actinic keratoses. Twenty patients had pharmacokinetic samples collected: 10 patients treated with Carac and 10 treated with Efudex® 5% Cream. Patients were treated for a maximum of 28 days with Carac, 1 g once daily in the morning; or Efudex® 5% Cream, 1 g twice daily, in the morning and evening. Steady-state plasma concentrations and the amounts of fluorouracil in urine resulting from the topical application of either product were measured.

Three patients who received Carac and nine patients who received Efudex® 5% Cream had measurable plasma fluorouracil levels; however, only one patient receiving Carac and six patients receiving Efudex® 5% Cream had a sufficient number of data points to calculate mean pharmacokinetic parameters.

Plasma Pharmacokinetic Summary

PK Parameter Carac
Efudex® (Mean ± SD)
Cmax 0.77 ng/mL 11.49 ± 8.24 ng/mL
Tmax 1.00 hr 1.03 ± 0.028 hr
AUC(0–24) 2.80 ng·hr/mL 22.39 ± 7.89 ng·hr/mL

Five of 10 patients receiving Carac and nine of 10 patients receiving Efudex® 5% Cream had measurable urine fluorouracil levels.

Urine Pharmacokinetic Summary

PK Parameter Carac (Mean ± SD)
Efudex® (Mean ± SD)
Cum Ae† 2.74 ± 5.22 mcg 119.83 ± 94.80 mcg
(min-max) (0-15.02) (0-329.87)
Max excretion rate 0.19 ± 0.52 mcg/hr 40.27 ± 47.14 mcg/hr
(min-max) (0-1.67) (0-164.5)
†Cumulative urinary excretion

Both Carac and Efudex® 5% Cream demonstrated low measurable plasma concentrations for fluorouracil when administered under steady-state conditions. Cumulative urinary excretion of fluorouracil was low for Carac and for Efudex®, corresponding to 0.055% and 0.24% of the applied doses, respectively.

Clinical Trials

Under the experimental conditions of the topical safety studies, Carac was not observed to cause contact sensitization. However, approximately 95% of subjects in the active arms of the Phase 3 clinical studies experienced facial irritation. Irritation is likely and sensitization is unlikely based on the results of the topical safety and Phase 3 studies.

Two Phase 3 identically designed, multicenter, vehicle-controlled, double-blind studies were conducted to evaluate the clinical safety and efficacy of Carac. Patients with five or more actinic keratoses (AKs) on the face or anterior bald scalp were randomly allocated to active or vehicle treatment in a 2:1 ratio. Patients were randomly allocated to treatment durations of 1, 2, or 4 weeks in a 1:1:1 ratio. They applied the study cream once daily to the entire face/anterior bald scalp. Each patient's clinical response was evaluated 4 weeks after the patient's last scheduled application of study cream. No additional posttreatment follow-up efficacy or safety assessments were performed beyond 4 weeks after the last scheduled application. The following graphs show the percentage of patients in whom 100% of treated lesions cleared, and the percentage of patients in whom 75% or more of treated lesions cleared. Treatment with Carac Cream for 1, 2, or 4 weeks is compared to treatment with vehicle cream. Outcomes from 1, 2, and 4 weeks of treatment with vehicle cream are pooled because duration of treatment with vehicle had no substantive effect on clearance. Results from the two Phase 3 studies are shown separately. Although all treatment regimens of Carac studied demonstrated efficacy over vehicle for the treatment of actinic keratosis, continuing treatment up to 4 weeks as tolerated results in further lesion reduction and clearing.

Percentage of Subjects with 100% Clearance

Percentage of Subjects with 100% Clearance - Illustration

Percentage of Subjects with at Least 75% Clearance

Percentage of Subjects with at Least 75% Clearance - Illustration

Clearance Clinical efficacy and safety in the treatment of AKs on the ears and other sun-exposed areas were not evaluated in the studies.

Medication Guide


(fluorouracil) Cream, 0.5%

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 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 you are 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 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 – unless 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.

Carac may be fatal to your pet if your pet licks or ingests Carac.

  • Avoid allowing pets to contact the Carac container or your skin where you applied Carac
  • Store Carac out of reach of pets
  • Safely discard or clean any cloth or applicator that may have Carac residue
  • Avoid applying Carac on your clothing, carpeting, or furniture.
  • If your pet starts vomiting or starts having a seizure after your pet licks or ingests Carac, seek immediate veterinary care for your pet.

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 2 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 chills, 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.

Storage information

Keep this medicine at room temperature 68° to 77° F (20° to 25° C). Throw away unused medicine. Keep this medicine out of 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 Carac 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.

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Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.