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Drug Interactions between Herceptin and Tykerb

This report displays the potential drug interactions for the following 2 drugs:

  • Herceptin (trastuzumab)
  • Tykerb (lapatinib)

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Interactions between your drugs

No interactions were found between Herceptin and Tykerb. This does not necessarily mean no interactions exist. Always consult your healthcare provider.


A total of 125 drugs are known to interact with Herceptin.


A total of 538 drugs are known to interact with Tykerb.

Drug and food interactions


lapatinib food

Applies to: Tykerb (lapatinib)

Take lapatinib on an empty stomach 1 hour before or 1 hour after a meal unless otherwise directed by your doctor. This will make it easier for your body to absorb the medication. The lapatinib dose is administered once daily and should not be divided. The usual dose of lapatinib is equal to 5 tablets. You may swallow each tablet one at a time, but take the entire lapatinib dose at the same time each day. If you are receiving therapy with lapatinib you should be advised to avoid grapefruits and grapefruit juice. Grapefruit can raise the levels of lapatinib in your body and lead to dangerous side effects.

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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.


Her2 inhibitors

Therapeutic duplication

The recommended maximum number of medicines in the 'HER2 inhibitors' category to be taken concurrently is usually one. Your list includes two medicines belonging to the 'HER2 inhibitors' category:

  • Herceptin (trastuzumab)
  • Tykerb (lapatinib)

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

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
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 interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.