Skip to Content

Drug interactions between bicalutamide and tamoxifen

Results for the following 2 drugs:

Interactions between your drugs


tamoxifen ↔ bicalutamide

Applies to:tamoxifen and bicalutamide

Consumer information for this interaction is not currently available.

GENERALLY AVOID: Long-term androgen deprivation therapy can prolong the QT interval. Theoretically, coadministration with other agents that can prolong the QT interval may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death. In a single, active-controlled, clinical study comparing abarelix to LHRH (luteinizing hormone releasing hormone) agonist plus nonsteroidal antiandrogen therapy, both therapies were found to prolong the mean Fridericia-corrected QT interval (QTcF) by more than 10 msec from baseline. In approximately 20% of patients in both groups, there were either changes from baseline QTc of greater than 30 msec or end-of-treatment QTc values exceeding 450 msec. Similar results were observed in two other Phase 3 studies with abarelix and the active-control treatments. In a randomized, active-controlled trial comparing degarelix to leuprolide, three patients (<1%) in the pooled degarelix group and four patients (2%) in the leuprolide 7.5 mg group had a QTcF of 500 ms or greater. From baseline to end of study, the median change was 12.3 msec for degarelix and 16.7 msec for leuprolide. Investigators believe that long-term androgen deprivation is responsible for these changes, as testosterone has been found to shorten ventricular repolarization. In general, the risk of an individual agent or a combination of agents causing ventricular arrhythmia in association with QT prolongation is largely unpredictable but may be increased by certain underlying risk factors such as congenital long QT syndrome, cardiac disease, and electrolyte disturbances (e.g., hypokalemia, hypomagnesemia). In addition, the extent of drug-induced QT prolongation is dependent on the particular drug(s) involved and dosage(s) of the drug(s).

MANAGEMENT: The benefits of androgen deprivation therapy should be carefully assessed against the potential risk in patients receiving other drugs known to prolong the QT interval. Electrolyte abnormalities should be corrected prior to initiating therapy, and periodic monitoring of electrocardiograms and electrolytes should be considered.


  1. "Product Information. Vantas (histrelin)." Endo Pharmaceuticals (formally Indevus Pharmaceuticals Inc), Lexington, MA.
  2. "Product Information. Zoladex (goserelin)." Zeneca Pharmaceuticals, Wilmington, DE.
  3. "Product Information. Eligard (leuprolide)." Sanofi Winthrop Pharmaceuticals, New York, NY.
  4. "Product Information. Firmagon (degarelix)." Ferring Pharmaceuticals Inc, Tarrytown, NY.
  5. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  6. "Product Information. Trelstar (triptorelin)" Pharmacia and Upjohn, Kalamazoo, MI.
  7. "Product Information. Plenaxis (abarelix)." Praecis Pharmaceuticals Inc, Waltham, MA.
  8. "Product Information. Lupron (leuprolide)." TAP Pharmaceuticals Inc, Deerfield, IL.
View all 8 references

Drug and food interactions


tamoxifen food

Applies to: tamoxifen

Talk to your doctor before using tamoxifen with soy products. There is some evidence that substances present in soy may stimulate breast tumor growth and interfere with the action of tamoxifen, although this has not been proven. Whether soy products are effective for hot flashes is also uncertain. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Switch to professional interaction data

Therapeutic duplication warnings

Therapeutic duplication is the use of more than one medicine from the same drug category or therapeutic class to treat the same condition. This can be intentional in cases where drugs with similar actions are used together for demonstrated therapeutic benefit. It can also be unintentional in cases where a patient has been treated by more than one doctor, or had prescriptions filled at more than one pharmacy, and can have potentially adverse consequences.


Antineoplastic hormones

Therapeutic duplication

The recommended maximum number of medicines in the 'antineoplastic hormones' category to be taken concurrently is usually one. Your list includes two medicines belonging to the 'antineoplastic hormones' category:

  • bicalutamide
  • tamoxifen

Note: The benefits of taking this combination of medicines may outweigh any risks associated with therapeutic duplication. This information does not take the place of talking to your doctor. Always check with your healthcare provider to determine if any adjustments to your medications are needed.

Drug Interaction Classification

The classifications below are a guideline only. The relevance of a particular drug interaction to a specific patient is difficult to determine using this tool alone given the large number of variables that may apply.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No information available.

Do not stop taking any medications without consulting your healthcare provider.

Disclaimer: Every effort has been made to ensure that the information provided by Multum 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. Multum's 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 that the drug or combination is safe, effective, or appropriate for any given patient. Multum Information Services, Inc. does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. Copyright 2000-2018 Multum Information Services, Inc. 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 drugs you are taking, check with your doctor, nurse, or pharmacist.