Testolactone (Oral)

Testolactone is a part of the group of medicine called antineoplastics and is used to treat some cases of breast cancer in females.


Testolactone is part of the group of medicines called antineoplastics.

Antineoplastics are a group of medicines used for the treatment of cancers. They work by destroying cancer cells, but they also destroy healthy cells, meaning that they can cause significant side effects. You should consider the positives and negatives of taking this medication with your doctor before you begin treatment.

Testolactone is used for the treatment of some cases of breast cancer in females. It should not be used in males or in cases where hyposensitivity to the drug has been observed.

Testolactone works by inhibiting the production of steroid aromatase activity and consequently reducing levels of estrone synthesis. This is the major source of estrogen in postmenopausal women. The consequence of this reduction can be a remission of female breast cancer.

Studies have shown that this inhibition may be irreversible and as such testolactone continues to have an effect on estrogen synthesis after drug withdrawal. Serious consideration should be made before undergoing irreversible treatment such as this.

This product is taken in tablet form and is orally consumed.

Testolactone is only available with a doctor's prescription and doses will be determined specifically for each patient.

Condition(s) treated

  • Breast Cancer

Type of medicine

  • Antineoplastic
  • Chemotherapy

Side Effects

Antineoplastics work by inhibiting cells within the body. As they are unable to distinguish between healthy and cancerous cells, they also attack the healthy cells in the body. This can lead to unwanted side effects. Some or none of the following side effects may occur when you are taking Testolactone.

Check with your doctor as soon as you are able to if you experience any of the following:

  • Numbness or tingling in the toes, fingers or face

Some side effects will occur that do not need to be medically treated. Your doctor may, however, be able to help alleviate the symptoms if you inform them of the side effects. If any of the following side effects become bothersome, tell your healthcare professional and they may be able to help you to alleviate the symptoms.

  • Diarrhea
  • Nausea
  • Vomiting
  • Loss of appetite
  • Pain or swelling in the feet or lower legs
  • Swelling or redness of the tongue

Other side effects can occur. If you experience other side effects then tell your doctor and they may either need to carry out tests or provide you with other advice on how to alleviate the side effects.


When taking testolactone it is very important that you make regular visits to your doctor. Your doctor will need to check that the medicine is working effectively and also look for any unwanted effects that may be occurring in your body.

This medicine must only ever be used as directed by a doctor. Using too much can be very dangerous.

The dose that you are given will be worked out exactly for you and should not be changed.

The dose of medicine that you take will depend on the strength of the medicine and your own personal conditions including weight, health and the severity of the condition to be treated.

Taking too great an amount will make the side effects worsen and taking too little will stop the drug from being effective.

Testolactone can cause serious nausea and vomiting, but you may need to take the drug for a period of weeks or months for the drug to have the desired effect. Even if you are feeling ill, you should not stop taking this medication without first consulting with your doctor. Your doctor may be able to provide you with further medication to alleviate the sickness caused by the drug.

If you throw up after taking a dose of the medicine, you should inform your doctor. Your doctor will advise you on whether to take the dose again or to wait until your next dose is due. The length of time between taking the dose and the sickness will be relevant, so try to be as accurate as you possibly can with the information you provide.

If you miss a dose of this medicine, you should take it as soon as possible, although not if it is then too close to your next dose being due. If you are close to your next dose then you should wait and resume your usual schedule. Never take a double dose of this medicine.

The recommended dose is 250 mg qid.


Before deciding to use a medicine you should consider the positives as well as the risks that it will put you under. Before taking this medicine make sure you discuss the following with your doctor.


Inform your healthcare professional of any allergies that you have. Allergies can make you react badly to some medications, so you should share any allergies with the doctor. It is particularly important to share information if you have ever had a bad reaction to any form of medication before.


This medication should not be taken when pregnant. The medication will be harmful to an unborn fetus.


There are no adequate studies to determine whether a child may be at risk from breastfeeding. Discuss this with your doctor and weigh the risks.

Other medications

Other medications that you are taking may interact with testolactone. Make sure that you have informed your doctor about all substances that you are taking. This includes vitamin supplements, herbal remedies, over the counter medicines and other prescription medicines. It is particularly important that you tell your doctor if you are taking any of the following drugs:

  • Acetyldigitoxin
  • Acetyldigoxin
  • Bevacizumab
  • Cabazitaxel
  • Cyclophosphamide
  • Cymarin
  • Deslanoside
  • Digitoxin
  • Digoxin
  • Docetaxel
  • Gitoformate
  • Lanatoside C
  • Metildigoxin
  • Oleandrin
  • Ouabain
  • Paclitaxel
  • Peruvoside
  • Proscillaridin
  • Trastuzumab

Other medical conditions

Other medical conditions can make this medication inappropriate for you. Inform your doctor of any conditions that you have or have had in the past. This is particularly important in cases of heart and kidney disease. If you have problems with liver function, you should also be clear about this with your medical professional.

Alcohol and tobacco

Alcohol and tobacco can interact with medication and can affect its productiveness in the body. You should discuss your use of alcohol and tobacco with your doctor, particularly in cases of excessive use.


Some serious side effects of the use of testolactone have been reported. In serious cases, the following side effects could occur:

  • Glossitis
  • Anorexia
  • Nausea
  • Vomiting
  • Increase in blood pressure
  • Edema of extremities
  • Paresthesia
  • Maculopapular erythema
  • Alopecia

Testolactone should not be used in the treatment of male breast cancer.

Testolactone should not be used in patients with a history of hypersensitivity to the drug.


Store the tablets in a sealed container at room temperature.

Keep away from heat, moisture and direct light.

Always keep medication away from children.

Do not keep outdated medication. Speak to your doctor about how to dispose of it.


Testolactone is used for the treatment of some types of breast cancer in females. It should never be used in the treatment of males.

Testolactone is an antineoplastic chemotherapy treatment and as such works by attacking cells in the body. The drug is unable to determine between healthy cells and cancerous cells, so side effects can occur.

Testolactone inhibits the production of estrogen and can lead to remission of breast cancer in some cases.

This inhibition has been shown to be an irreversible process in many cases once the medication has been withdrawn.

Testolactone is taken as a tablet and doses will be closely determined for each patient. The dose should not be amended or changed unless the doctor directs it.

In many cases, testolactone will induce nausea and vomiting. In these cases, it is important that you do not stop taking the medication without discussing this with your doctor first. If you vomit after taking the medicine you should consult your doctor as to whether you should take an additional dose of the treatment. The treatment can take several weeks or months to be effective and you may suffer sickness throughout this period.

This medication should not be taken when pregnant. It can be harmful to the unborn fetus and can cause long-term effects. If you are pregnant or trying to get pregnant, discuss this with your doctor before taking the medicine.

Last Reviewed:
December 23, 2017
Last Updated:
April 05, 2018
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