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Eulexin Side Effects

Generic Name: flutamide

Note: This page contains information about the side effects of flutamide. Some of the dosage forms included on this document may not apply to the brand name Eulexin.

For the Consumer

Applies to flutamide: oral capsule, oral tablet

In addition to its needed effects, some unwanted effects may be caused by flutamide (the active ingredient contained in Eulexin). In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking flutamide:

More common:
  • Black, tarry stools
  • bloody or cloudy urine
  • continuing diarrhea
  • continuing stomach pain
  • difficult, burning, or painful urination
  • frequent urge to urinate
  • pale skin
  • troubled breathing with exertion
  • unusual bleeding or bruising
  • unusual tiredness or weakness
Less common:
  • Blurred vision
  • chest pain
  • chills
  • cough
  • difficulty with breathing
  • dizziness
  • drowsiness
  • fever
  • headache
  • nervousness
  • pounding in the ears
  • shortness of breath
  • slow or fast heartbeat
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • swelling
  • swollen glands
  • Abdominal or stomach pain
  • clay-colored stools
  • dark urine
  • general tiredness and weakness
  • itching
  • light-colored stools
  • loss of appetite
  • nausea and vomiting
  • rash
  • tumor
  • unpleasant breath odor
  • upper right abdominal pain
  • vomiting of blood
  • yellow eyes and skin
Incidence not known:
  • Back, leg, or stomach pains
  • bleeding gums
  • blistering, peeling, or loosening of the skin
  • bluish-colored lips, fingernails, or palms
  • discoloration of the urine
  • dizziness or lightheadedness
  • flushing or redness of the skin
  • general body swelling
  • headache
  • itching
  • joint or muscle pain
  • nosebleeds
  • rapid heart rate
  • red irritated eyes
  • red skin lesions, often with a purple center
  • unusually warm skin

If any of the following symptoms of overdose occur while taking flutamide, get emergency help immediately:

Symptoms of overdose:
  • Goosebumps
  • shakiness and unsteady walk
  • tearing of the eyes
  • unsteadiness, trembling, or other problems with muscle control or coordination
  • weight loss

Minor Side Effects

Some of the side effects that can occur with flutamide may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common:
  • Decreased interest in sexual intercourse
  • diarrhea
  • feeling of warmth
  • inability to have or keep an erection
  • indigestion
  • loss in sexual ability, desire, drive, or performance
  • passing of gas
  • redness of the face, neck, arms and occasionally, upper chest
  • stomach pain, fullness, or discomfort
  • sudden sweating
  • swelling of the breasts or breast soreness in both females and males
Less common:
  • Depression
  • drowsiness
  • fear or nervousness
  • mood or mental changes

For Healthcare Professionals

Applies to flutamide: oral capsule


In general, flutamide (the active ingredient contained in Eulexin) has been used concomitantly with LHRH agonists or after bilateral orchiectomy. Therefore, little data are available on the side effects of flutamide alone.[Ref]


Nineteen cases of severe flutamide (the active ingredient contained in Eulexin) related hepatotoxicity were reported by the FDA in 1993. The flutamide related hepatitis developed 56 to 80 days after the beginning of therapy and was mainly cytolytic. Four of the cases involved massive hepatic necrosis with fatal outcomes. The mechanism of action was believed to be direct hepatotoxicity.

In a study of 1,091 patients with prostate cancer treated with flutamide and an LHRH agonist, four patients (0.36%) developed severe hepatotoxicity in the first four weeks of therapy. Serum aminotransferases increased more than four times normal values. Alkaline phosphatase increased more than six times normal values in one patient. Total bilirubin was elevated in two patients. Only two patients developed clinical manifestations, including fatigue, anorexia, weight loss, nausea, and vomiting. None of the remaining 1,089 patients had significant elevations in liver function tests although transient, mild elevations in AST and ALT occasionally occurred.

In most cases, discontinuation of flutamide results in resolution of symptoms.

A case of fatal liver complications has been reported where the drug was prescribed for an 18 year old woman for the treatment of minor acne and hirsutism. The risk of lethal hepatic complications makes the risk-benefit ratio unacceptable when flutamide is being considered to treat disorders such as polycystic ovaries, and especially for benign complaints such as alopecia, hirsutism, and acne.[Ref]

Hepatic side effects have included elevations in serum transaminases as well as cases of cholestatic jaundice, hepatic necrosis, hepatic encephalopathy, and fatal hepatotoxicity.[Ref]


Hematologic side effects have included anemia (6%), leukopenia (3%), and thrombocytopenia (1%). Flutamide (the active ingredient contained in Eulexin) has also been implicated in cases of methemoglobinemia, sulphemoglobinemia and neutropenia. In addition, eosinophilia has been reported in association with some cases of hepatotoxicity.[Ref]

Nervous system

Nervous system side effects have been reported in less than 1% of patients and include drowsiness, dizziness, sedation, and confusion.[Ref]


Renal side effects including renal failure (in association with severe hepatotoxicity) have been reported.[Ref]


Cardiovascular side effects reported include hypertension (1%), thromboembolism, and edema.[Ref]


Pseudoporphyria (blisters, increased skin fragility, and erosions in sun-exposed areas) was reported in a 68-year-old man being treated for prostate cancer with appropriate doses of flutamide (the active ingredient contained in Eulexin) and goserelin. The patient presented with skin fragility and blisters on the back of the hands. After replacing the flutamide with bicalutamide, the lesions healed.[Ref]

Dermatologic side effects including rash (3%), alopecia, sweating, and cases of photosensitivity/photoallergy have been reported. One case of flutamide-induced pseudoporphyria has also been reported.[Ref]


Endocrine side effects including hot flashes (29% to 63%), gynecomastia (up to 19%), fever, and breast tenderness (7%) have been reported.[Ref]


Two female patients receiving flutamide (the active ingredient contained in Eulexin) for the treatment of bulimia nervosa noted decreased symptoms within a week after initiation of therapy. Both patients relapsed after the drug was later withdrawn.[Ref]

Gastrointestinal side effects including mucositis, diarrhea, nausea, vomiting, abdominal pain, anorexia, and either weight loss or gain have been reported.[Ref]


Musculoskeletal side effects including muscle cramps in up to 15% of patients have been reported.[Ref]


Psychiatric side effects including depression, anxiety, and nervousness have been reported. One case report of mania has also been reported.[Ref]


Genitourinary side effects including impotence and loss of libido have been reported.[Ref]


Several studies have described a flutamide (the active ingredient contained in Eulexin) withdrawal syndrome in which significant reductions in prostate-specific antigen (PSA) levels are noted following the discontinuation of flutamide therapy in patients with hormone-refractory prostate cancer.

Several studies have evaluated the effect of concurrent discontinuation of flutamide and initiation of aminoglutethimide therapy in patients with hormone-refractory prostate cancer. In one study, serum PSA levels declined by more than 80% for more than four weeks in 14 out of 29 (48%) patients. Clinical improvement was also noted. Some authors propose prolonged flutamide therapy may result in the selective proliferation of cancer cell lines with androgen receptors which recognize hydroxyflutamide as an androgenic agonist. Additional research is needed to fully evaluate this phenomenon.[Ref]

Other side effects have included flutamide withdrawal syndrome.[Ref]


Respiratory side effects including one case of pneumonitis have been reported.[Ref]


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16. Rosenthal SA, Linstadt DE, Leibenhaut MH, Andras EJ, Brooks CP, Stickney DR, Chang GC, Wolkov HB, Gilbert RM "Flutamide-associated liver toxicity during treatment with total androgen suppression and radiation therapy for prostate cancer." Radiology 199 (1996): 451-5

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33. Rousseau L, Dupont A, Labrie F, Couture M "Sexuality changes in prostate cancer patients receiving antihormonal therapy combining the antiandrogen flutamide with medical (LHRH agonist) or surgical castration." Arch Sex Behav 17 (1988): 87-98

34. Kelly WK, Scher HI "Prostate specific antigen decline after antiandrogen withdrawal: the flutamide withdrawal syndrome." J Urol 149 (1993): 607-9

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Not all side effects for Eulexin may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.