Tukysa (tucatinib) is a brand-name oral tablet that’s prescribed for HER2-positive breast and colorectal cancers in certain adults. Tukysa has interactions with some other drugs and certain supplements. Examples include atorvastatin (Lipitor) and St. John’s wort.

An interaction occurs when one substance causes another substance to have a different effect than expected.

To learn more about Tukysa’s interactions, keep reading. For additional information about Tukysa, including details about its uses, see this article.

Before you start treatment with Tukysa, tell your doctor and pharmacist which prescription, over-the-counter, and other medications you take. By sharing this information with them, you may help prevent possible interactions. (To learn whether Tukysa interacts with supplements, herbs, or vitamins, see the “Tukysa and other interactions” section below.)

If you have questions about drug interactions that may affect you, talk with your doctor or pharmacist.

Here’s a table of drugs that can interact with Tukysa. Keep in mind that this table doesn’t include all drugs that may interact with Tukysa. Some of these interactions are described in detail just below in “Drug interactions in depth.”

Drug class or drug nameDrug examplesInteraction result with Tukysa
certain seizure medications• carbamazepine (Tegretol, others)
• phenytoin (Dilantin)
can make Tukysa less effective
certain statins• atorvastatin (Lipitor)
• lovastatin (Altoprev)
• simvastatin (Zocor, FloLipid)
can increase the risk of side effects of certain statins
certain antipsychotics• lurasidone (Latuda)
• quetiapine (Seroquel)
can increase the risk of side effects of certain antipsychotics
certain sedatives• midazolam
• triazolam (Halcion)
can increase the risk of side effects of certain sedatives
certain blood thinners• dabigatran (Pradaxa)
• edoxaban (Savaysa)
• rivaroxaban (Xarelto)
can increase the risk of side effects of certain blood thinners
clopidogrel (Plavix)can increase the risk of side effects of Tukysa
digoxin (Lanoxin)can increase the risk of side effects of digoxin
gemfibrozil (Lopid)can increase the risk of side effects of Tukysa
rifampin (Rifadin, Rimactane)can make Tukysa less effective
teriflunomide (Aubagio)can increase the risk of side effects of Tukysa

There aren’t any known interactions between Tukysa and alcohol. However, your doctor may advise you to avoid or limit alcohol consumption during Tukysa treatment.

This is because drinking alcohol while taking the drug may worsen some of Tukysa’s side effects. For example, you may experience:

In addition, consuming large amounts of alcohol can cause liver damage. Tukysa may also cause liver damage as a side effect. This means that drinking alcohol during Tukysa treatment may increase the risk of liver problems.

If you consume alcohol during Tukysa treatment, these side effects may be more likely to occur. If you have questions about drinking alcohol while taking Tukysa, talk with your doctor.

Here’s a closer look at certain drug interactions of Tukysa.

Certain seizure medications

Seizure medications are used to treat seizure disorders, such as epilepsy. Some are also prescribed for other uses, such as bipolar disorder or trigeminal neuralgia (a type of nerve pain).

Interaction result: Taking certain seizure medications with Tukysa can make Tukysa less effective.

Interaction explained: Certain seizure medications increase the activity of an enzyme that helps clear Tukysa from your body, called cytochrome P450 3A4 (CYP3A4). By increasing CYP3A4 activity, these seizure medications can lower the amount of Tukysa in your body. This can make Tukysa less effective at treating your cancer.

Examples of seizure medications: Here are some seizure medications that may interact with Tukysa:

  • carbamazepine (Tegretol, others)
  • phenytoin (Dilantin)

Steps you or your doctor may take: Your doctor will likely avoid prescribing Tukysa with these seizure medications. If you take one of these drugs, your doctor may switch you to a different treatment for your condition before prescribing Tukysa. If this isn’t possible, they may prescribe a treatment other than Tukysa for your cancer.

If you have questions about taking Tukysa with a seizure medication, talk with your doctor or pharmacist.

Certain statins

Statin drugs are commonly prescribed to lower high cholesterol levels.

Interaction result: Taking Tukysa with certain statins can raise the risk of side effects from the statin. Examples of statin side effects include:

  • headache
  • nausea
  • muscle pain
  • liver problems.

Interaction explained: Tukysa slows the activity of an enzyme that helps clear certain statins from your body, called CYP3A4. By slowing CYP3A4 activity, Tukysa can make these statins build up in your body. Having a higher level of statin in your body is more likely to cause side effects.

Examples of statin drugs: Here are some statins that may interact with Tukysa:

  • atorvastatin (Lipitor)
  • lovastatin (Altoprev)
  • simvastatin (Zocor, FloLipid)

Steps you or your doctor may take: If you take one of these statins with Tukysa, your doctor may prescribe a dosage of the statin that’s lower than usual. Or they may recommend switching to a different statin that doesn’t interact with Tukysa.

If you have new or increased statin side effects when taking these drugs together, tell your doctor right away.

If you have questions about taking Tukysa with a statin, talk with your doctor or pharmacist.

Digoxin

Digoxin (Lanoxin) is used to treat certain heart conditions, such as heart failure and atrial fibrillation (AFib).

Interaction result: Taking Tukysa with digoxin can raise the risk of digoxin side effects. Examples include:

  • vision changes
  • confusion
  • nausea and vomiting

Interaction explained: Tukysa reduces the activity of a protein that helps clear digoxin from your body, called P-glycoprotein (P-gp). By reducing P-gp activity, Tukysa can increase the level of digoxin in your body. Having a higher level of digoxin in your body is more likely to cause side effects.

Steps you or your doctor may take: If you take Tukysa with digoxin, your doctor may prescribe a dosage of digoxin that’s lower than usual. They will also likely monitor the level of digoxin in your blood.

If you have new or increased digoxin side effects when taking these drugs together, tell your doctor right away.

If you have questions about taking Tukysa with digoxin, talk with your doctor or pharmacist.

Tukysa may have other interactions, such as with supplements, foods, vaccines, or even lab tests. You’ll find details below. Keep in mind that the following information does not include all other possible interactions with Tukysa.

Tukysa interactions with supplements

Before you start treatment with Tukysa, tell your doctor and pharmacist which supplements, herbs, and vitamins you take. By sharing this information with them, you may help prevent possible interactions.

If you have questions about drug interactions that may affect you, talk with your doctor or pharmacist.

Tukysa interactions with herbs

Doctors will typically recommend you avoid taking St. John’s wort with Tukysa. St. John’s wort is a herbal supplement that may be used to treat depression and other conditions.

St. John’s wort may speed up the activity of an enzyme in your body called CYP3A4. This enzyme helps break down Tukysa.

By speeding up this enzyme, St. John’s wort can cause Tukysa to break down more quickly. This may lead to a lower level of Tukysa in your system and the drug may not work as effectively to treat your cancer.

Your doctor may be able to suggest a treatment option other than St. John’s wort.

Tukysa and vitamins

There are no specific reports of vitamins interacting with Tukysa. However, that doesn’t mean vitamin interactions won’t occur or be recognized in the future. Because of this, you should talk with your doctor or pharmacist before taking any vitamin product with Tukysa.

Tukysa and food

There were no reports of food interactions with Tukysa. If you’d like to learn more about eating certain foods during treatment with Tukysa, talk with your doctor.

Tukysa and vaccines

There aren’t any known interactions between Tukysa and vaccines. However, you should talk with your doctor if you have questions about receiving vaccines while taking Tukysa.

Tukysa and lab tests

Tukysa isn’t known to interact with any lab tests. If you have concerns about this medication interacting with lab tests, talk to your doctor.

TUKYSA INTERACTION WITH CANNABIS OR CBD

Cannabis (often called marijuana) and cannabis products, such as cannabidiol (CBD), have not been specifically reported to interact with Tukysa.

However, you should talk with your doctor before using cannabis in combination with Tukysa, as an interaction may still be possible. The impact of cannabis may also affect how well you stick to your Tukysa treatment plan.

Note: Cannabis is illegal at a federal level but is legal in many states to varying degrees.

Certain medical conditions and other factors may increase the risk of interactions with Tukysa. Before you take this drug, be sure to talk with your doctor about your health history. Tukysa may not be the right treatment option if you have certain medical conditions or other factors affecting your health.

Health conditions or factors that might interact with Tukysa include:

  • Liver problems: Tukysa can cause liver damage. So if you already have a liver problem, Tukysa could make it worse. Your doctor will likely monitor your liver function during your treatment. If you have a severe liver problem, you may also have a higher risk of other Tukysa side effects. That’s because your liver may not break down Tukysa effectively, so it could build up in your body. If you have a severe liver problem, your doctor will likely prescribe a dosage of Tukysa that’s lower than usual.
  • Allergic reaction: If you’ve had an allergic reaction to Tukysa or any of its ingredients, your doctor will likely not prescribe Tukysa. Taking the drug could cause another allergic reaction. You can ask them about other treatments that may be better choices for you.
  • Breastfeeding: It’s not known whether Tukysa passes into breast milk or what effects it may have on a child who is breastfed. Due to the risk of serious side effects, your doctor will likely recommend that you don’t breastfeed while taking Tukysa and for 1 week after your last dose. If you’re breastfeeding or planning to, talk with your doctor before taking Tukysa. They can talk with you about treatment options and ways to feed your child.
  • Pregnancy: Based on animal studies and the way the drug works, Tukysa may cause fetal harm if used during pregnancy. If you’re pregnant or planning to become pregnant, tell your doctor before starting Tukysa. They can advise you on the right treatment plan for you. If you or your sexual partner are able to become pregnant, you should use birth control while taking Tukysa and for 1 week after your last dose.

You can take certain steps to help prevent interactions with Tukysa. Your doctor and pharmacist are key resources, so reach out to them before starting treatment. For example, you should plan to do the following:

  • Let them know if you drink alcohol or use cannabis.
  • Tell them about any other medications you take, as well as any supplements, herbs, and vitamins.
  • Create a medication list, which your doctor and pharmacist can help you fill out.

It’s also important to read the Tukysa label and other paperwork that may come with the drug. The label may have colored stickers that mention an interaction. And the paperwork, sometimes called the medication guide or patient package insert, may contain details about interactions.

If Tukysa doesn’t come with paperwork, you can ask your pharmacist to print a copy. If you need help reading or understanding this information, ask your doctor or pharmacist.

You can also help prevent interactions with Tukysa by taking it exactly as your doctor prescribes.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.