Side Effects Of Flutamide (Eulexin): Hot Flashes, Diarrhea, More

Flutamide (Eulexin) is a prescription medicine that is used in the treatment of prostate cancer in men. 

Flutamide is a type of nonsteroidal anti-androgen or anti-testosterone drug. 

Testosterone is the primary male hormone (androgen) that promotes the spread and growth of prostate cancer in men. 

Flutamide blocks the androgen or testosterone receptors in the body. 

This results in inhibiting the stimulating effects of testosterone and slowing the spread and growth of cancer cells. 

Flutamide is prescribed together with another drug referred to as a LHRH (luteinizing hormone-releasing hormone) agonist. 

A LHRH agonist is a drug that helps reduce the amount of testosterone produced by the testicles. 

In this article, we will explore flutamide in detail and learn about the side effects and risks of taking it, the warnings and precautions for Eulexin, what to avoid while taking it, how to take it, and whether it has been discontinued. 

Possible Side Effects of Taking Flutamide 

1) Allergic reaction

You should seek emergency medical care if you develop signs and symptoms of an allergic reaction after taking flutamide. 

These include the following:

  • Hives
  • Swelling of the throat, lips, tongue, or throat
  • Difficulty breathing

2) Diarrhea (Loose Stool)

Diarrhea is one of the common adverse effects of taking flutamide. Diarrhea, along with nausea or vomiting, occurs in about one in 10 patients taking flutamide. 

You should drink lots of fluids as instructed by your healthcare physician to decrease the risk of getting dehydrated. 

You may also want to reduce your intake of dairy products while increasing the intake of fruits, veggies, and whole grains. Stop any laxatives you are taking. 

Your physician may prescribe medicines such as loperamide to help control the symptoms of loose stools. You must inform your physician immediately if you develop:

  • Severe and continuing diarrhea
  • Signs and symptoms of dehydration such as decreased urination, dizziness, etc. 

3) Hot Flashes

Hot flashes are the most common side effect of taking flutamide and occur in more than 50% of the patients taking it. 

Managing hot flashes may involve using fans and wearing comfortable clothing, like lightweight and loose-fitting cotton garments.

4) Reduced libido

Loss of sexual ability and interest is also a very common side effect of taking flutamide and occurs in 36% of patients taking the drug. 

While side effects are expected to resolve after stopping flutamide, it’s important to consult with your healthcare provider. 

Maintaining physical contact with your partner can help provide emotional support during this period.

5) Impotence

Impotence occurs in about 31% of patients taking flutamide. As with reduced libido, impotence should also disappear as the Eulexin treatment finishes. 

Communication with your partner is very important for maintaining a healthy relationship. Talk about your feelings to them and find out other ways to stay close.  

6) Gynecomastia and/or breast tenderness

Flutamide may impact hormone levels, potentially leading to side effects such as gynecomastia. 

Gynecomastia or male breast enlargement occurs in about 9% of patients taking flutamide. You may also develop breast tenderness along with swelling. 

If you experience any concerns, discuss the treatment options for gynecomastia with your healthcare physician.

7) Liver problems

Flutamide may result in serious liver issues. Call your physician immediately if you develop:

  • Nausea, loss of appetite, pain in the upper part of the stomach
  • Flu-like signs and symptoms, tiredness, and itching
  • Clay-colored stools, dark urine, or
  • Jaundice (characterized by yellowing of the eyes or skin)

Some of the other side effects of taking flutamide are:

  • Rash 
  • Swelling of the feet, hands, lower legs, or ankles
  • Lack of appetite
  • Confusion
  • Depression
  • Anxiety
  • Drowsiness
  • Orange or blue-green-colored urine

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What to Avoid While Taking Flutamide 

1) Drug Interactions

It is not recommended to use flutamide with the following drugs: 

  • Idelalisib
  • Ivacaftor
  • Levoketoconazole
  • Pexidartinib
  • Methotrexate
  • Warfarin

If you have to take flutamide with any of these drugs, your physician may change the dosage of the drugs or the frequency of both or one of the drugs. 

2) Dairy

To prevent the occurrence of diarrhea, you should avoid consuming dairy products, including yogurt, milk, and cheese. 

3) Laxatives

Avoid using laxatives while consuming Eulexin. 

4) Alcohol and Smoking

Avoid consuming alcoholic beverages and marijuana (cannabis) while using flutamide. 

You also want to avoid tobacco smoking while using flutamide since aniline, an ingredient present in the drug, can cause problems in smokers. 

5) Taurine and Maitake

Other substances that should be avoided while taking Eulexin are taurine and maitake. 

Maitake is a kind of mushroom that has possible antitumor effects and may raise blood levels of flutamide. 

Taurine is a type of organic compound that may be present in many popular energy drinks, and flutamide may interact with taurine. 

How to Take Eulexin

Flutamide is available in capsule form that you have to take orally (by mouth). Flutamide is generally taken every eight hours (i.e., thrice daily) without or with food. 

It is recommended to ingest flutamide at about the same time every day. Carefully follow the instructions on the prescription label and ask the doctor to explain the part you can’t understand. 

Take the drug exactly as instructed by your physician. Do not consume less or more of it. Furthermore, do not take it more frequently than prescribed to you by the doctor. 

Continue taking flutamide in combination with the luteinizing hormone-releasing hormone agonist medicine even if you start feeling better. 

Don’t reduce the dosage or stop any of the drugs without consulting your physician. 

Drink lots of liquids. Your physician may advise a specific diet to prevent the side effects of diarrhea. 

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Precautions For Taking Eulexin

To ensure that you can safely take the drug, tell your healthcare provider:

  • If you have a medical history of liver ailments, a deficiency of glucose-6-phosphate dehydrogenase or G6PD enzyme, or hemoglobin M disease
  • If you are a smoker
  • What other medicines you are taking, including all the nonprescription and prescription drugs, herbal products, vitamins, and nutritional supplements
  • If you take an anticoagulant medicine (blood thinner) such as warfarin

Pregnant or lactating women should avoid touching or taking flutamide accidentally.

Flutamide may result in facial flushing. You should consult your physician about the use of alcohol while taking flutamide, as drinking alcohol may worsen facial flushing. 


Has Flutamide Been Discontinued? 

Flutamide was approved in the United States for use in the treatment of prostate cancer in 1989. Since then, it has been used extensively globally. 

The antiandrogen effects of the drug have also been used to treat conditions with increased levels of androgens both in women and men. These include hirsutism, benign prostatic hypertrophy, and acne. 

However, due to the potential serious adverse effects of flutamide on the liver, its use other than in the treatment of prostate cancer is no longer recommended. 

How Should I Store Flutamide?

You should keep flutamide in the same container in which it came. Tightly close the container and keep it safely in a place that is out of children’s reach. 

Store flutamide at room temperature. The drug should be kept away from excess moisture, light, and heat. You should avoid storing it in your bathroom.

How Should I Dispose Of Flutamide?

You should dispose of the unneeded medicine through the drug take-back program. Do not flush flutamide in the toilet. 

You may get more information about the program from your pharmacist or visit the US Food and Drug Administration’s (FDA) website to learn more. 

What Should You Do If You Forget Or Miss A Dose Of Flutamide?

You should take the drug as soon as possible, but skip it if it’s time for the upcoming dose. Follow the regular dosage schedule, and don’t consume two doses of flutamide at any one time. 

What Should You Do In Case Of An Overdose Or Emergency?

In case of an overdose, call emergency medical help. 


Flutamide is a type of nonsteroidal anti-androgen or anti-testosterone drug that is used in the treatment of prostate cancer in men. It is available only by a doctor’s prescription. 

While taking flutamide, it is important to follow the instructions of your physician. Keep all your laboratory and doctor appointments. 

Make sure to call your physician if you notice any of the side effects due to flutamide. Do not stop the drug suddenly or without consulting your physician.


Johnson DB, Sonthalia S. Flutamide. [Updated 2023 May 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-.

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