Keytruda (pembrolizumab) is a brand-name drug that’s prescribed for several forms of cancer in adults and certain children. Currently, Keytruda isn’t known to interact with other medications or supplements.

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

Keytruda comes as a solution for intravenous (IV) infusion.

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

There currently aren’t reports of other medications interacting with Keytruda. But this doesn’t mean interactions won’t be discovered at a later date. For example, new drugs may be developed that interact with Keytruda.

Before you start treatment with Keytruda, 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 with drugs that may be discovered during your Keytruda treatment.

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

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

This is because drinking alcohol while receiving the drug may worsen some of Keytruda side effects, such as:

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

Alcohol may also increase the risk of cancer recurrence (coming back after treatment) or development of new cancers. Your doctor may recommend limiting alcohol consumption during or after your cancer treatment.

If you consume alcohol during Keytruda treatment, side effects of the drug may be more likely to occur. If you have questions about drinking alcohol during Keytruda treatment, talk with your doctor.

Keytruda 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 Keytruda.

Keytruda interactions and supplements

It’s possible for drugs to interact with supplements such as vitamins and herbs.

Keytruda interactions and herbs

There are no specific reports of herbs interacting with Keytruda. However, that doesn’t mean herbal interactions won’t occur or be recognized in the future. Because of this, it’s important to check with your doctor or pharmacist before taking any of these products during Keytruda treatment.

Keytruda interactions and vitamins

There are no specific reports of vitamins interacting with Keytruda. 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 Keytruda.

Keytruda interactions and food

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

Keytruda interactions and vaccines

There aren’t any known interactions between Keytruda and vaccines. Talk with your doctor or pharmacist to see whether you’re due for any vaccines.

Keytruda interactions with lab tests

Keytruda may interfere with the results of the purified protein derivative skin test for tuberculosis (TB). This is a skin test that determines if you have TB (a type of bacterial infection).

Treatment with Keytruda may cause a false-negative result on this test. This means if you have TB in your system, the test won’t show it.

Due to this interaction, your doctor may test you for TB before starting treatment with Keytruda or use a different test to check for TB during your treatment. Or they may delay TB testing until at least 6 weeks after Keytruda treatment.

For additional information, talk with your doctor or pharmacist.

KEYTRUDA INTERACTION AND CANNABIS OR CBD

Cannabis (often called marijuana) and cannabis products, such as cannabidiol (CBD), have not been specifically reported to interact with Keytruda. However, as with any drug or supplement, talk with your doctor before using cannabis in combination with Keytruda. The effect of cannabis may affect how well you stick to your Keytruda 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 Keytruda. Before you take this drug, be sure to talk with your doctor about your health history. Keytruda 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 Keytruda include:

  • Immune system conditions: If you have an immune system condition, such as lupus or Crohn’s disease, Keytruda could worsen symptoms of your condition. Your doctor can provide more information about this risk and whether treatment with Keytruda is safe for you.
  • Nervous system conditions: If you have a nervous system condition, such as myasthenia gravis, Keytruda could worsen symptoms of your condition. Talk with your doctor to determine whether Keytruda is safe for you.
  • Past radiation therapy to your chest: People who received a certain amount of radiation therapy to the chest area were not permitted to participate in some clinical trials of Keytruda. If you’ve had this type of therapy, talk with your doctor to learn more about the risks and benefits of Keytruda treatment.
  • Received an organ transplant in the past: Keytruda works by affecting activity in your immune system. It’s possible that treatment with Keytruda could result in organ transplant rejection. Talk with your doctor to learn more about this risk and whether Keytruda treatment is safe for you.
  • Received or plan to receive an allogeneic stem cell transplant: An allogeneic stem cell transplant uses stem cells from a donor. Serious complications can happen if you receive Keytruda before or after an allogeneic stem cell transplant. If your doctor determines Keytruda is safe for you and you’ve received or will receive this type of transplant, your doctor will closely monitor you for complications.
  • Allergic reaction: If you’ve had an allergic reaction to Keytruda or any of its ingredients, your doctor will likely not prescribe Keytruda. Receiving 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 it’s safe to receive Keytruda while breastfeeding. There isn’t enough information to determine whether the drug passes into breast milk or what effects Keytruda may have on a child who is breastfed. If you’re breastfeeding or planning to, talk with your doctor before receiving Keytruda. They can talk with you about treatment options and ways to feed your child.
  • Pregnancy: There haven’t been enough clinical trials to determine whether Keytruda is safe to receive while pregnant. Animal studies show that the drug may cause congenital anomalies (commonly known as birth defects) or pregnancy loss. However, it’s important to note that animal studies don’t always indicate what may happen in humans. If you’re pregnant or planning to become pregnant, tell your doctor before starting Keytruda. They can advise you on the right treatment plan for you.

You can take certain steps to help prevent interactions with Keytruda. 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 Keytruda 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 Keytruda 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 Keytruda by using 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.