8 Verzenio Interactions and How to Manage Them

Verzenio (abemaciclib) is an oral medication used to treat certain types of hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) breast cancer. It’s often taken twice a day, either alone or with other cancer treatments. For many people, it’s part of a long-term treatment plan.

Verzenio can interact with other medications, supplements, and even certain foods. Some interactions can raise your risk of side effects. Others can affect how well Verzenio works.

Managing interactions is part of prioritizing your health as you fight breast cancer. Here’s what you should know.

Verzenio interactions at a glance

Verzenio interacts with several medications, supplements, and foods. Depending on the interaction, your healthcare team may recommend avoiding the combination, adjust your Verzenio dosage, or monitor you more closely.

Important Verzenio interactions include:

• Azole antifungals, including ketoconazole (Nizoral), fluconazole (Diflucan), itraconazole (Sporanox), and posaconazole (Noxafil)

• Ritonavir and other medications that contain ritonavir, such as Paxlovid (nirmatrelvir / ritonavir)

• Certain heart medications, including diltiazem (Cardizem), verapamil (Calan SR, Verelan), and amiodarone (Pacerone)

• Grapefruit and grapefruit juice

• Anti-seizure medications such as carbamazepine (Tegretol, Equetro), phenobarbital (Luminal), and phenytoin (Dilantin)

• Antibiotics such as clarithromycin (Biaxin XL) and erythromycin (Ery-Tab)

• St. John’s wort

• Rifampin

• Antidepressants such as nefazodone

• Stimulant medications such as modafinil (Provigil) and armodafinil (Nuvigil)

Make sure your oncologist knows about all medications you’re taking, including those unrelated to your cancer treatment. Give an oncologist a list of the medications you take, including over-the-counter medications and supplements. They can check for interactions.

Here are eight key Verzenio interactions to keep in mind.

1. Azole antifungals like ketoconazole

Verzenio interacts with several azole antifungals, including ketoconazole, fluconazole, and itraconazole. Azole antifungals make it harder for your liver to break down Verzenio. This raises Verzenio levels in your blood, increasing the risk of side effects such as nausea and diarrhea.

Verzenio and ketoconazole shouldn’t be taken together. With other azole antifungals, an oncologist may lower your dose of Verzenio. And they may increase your Verzenio dose once you stop taking the azole antifungal (after your infection has resolved).

Speak to your oncologist if you have any concerns about combining azole antifungals with Verzenio.

2. Paxlovid and other ritonavir-containing medications

Paxlovid is a treatment option to lessen the severity of COVID-19. It’s a combination medication containing two active ingredients. One of them, ritonavir, interacts with many medications.

Ritonavir slows the breakdown of Verzenio. This increases Verzenio levels in your blood when the two medications are taken at the same time.

Ritonavir is also found in several HIV treatments. One example is Kaletra (lopinavir / ritonavir). It also used to be an ingredient in certain hepatitis C medications. But those products have been discontinued.

Speak with your oncologist if you’re prescribed ritonavir or any ritonavir-containing medication. They’ll likely want to adjust your Verzenio dose to ensure you’re getting one that’s safe for you.

3. Certain heart medications

Diltiazem and verapamil treat heart conditions such as arrhythmias (abnormal heart rhythms) and chest pain. Some people take them to treat high blood pressure. Amiodarone is another medication that treats arrhythmias. But it works in a different way.

All three medications can cause drug interactions. Diltiazem, verapamil, and amiodarone affect how your body breaks down Verzenio. They can slow down Verzenio’s breakdown, causing it to build up. Side effects are more likely to happen as a result.

Make sure your oncologist is aware of your heart conditions and medications. They can adjust your Verzenio dose, especially if you’re stable on your cardiac regimen. Alternatively, a cardiologist may change your heart medication to one that doesn’t interact with Verzenio. These types of changes are made on a case-by-case basis.

4. Grapefruit

Grapefruit can cause a similar interaction as some of the medications above. Think of it as something that can “boost” your medication dose more than intended.

Eating or drinking grapefruit products can raise Verzenio levels in your body. This increases the risk of side effects. So it’s a good idea to avoid grapefruit products entirely while you’re taking Verzenio.

Apple juice, orange juice, and tomato juice don’t interact with Verzenio. They’re great alternatives to grapefruit. An oncologist can tell you about foods and drinks to avoid while taking Verzenio or other cancer medications.

5. Anti-seizure medications

Carbamazepine, phenobarbital, and phenytoin are prescription medications that treat specific types of seizures. But they may affect other medications that you take, such as Verzenio.

Certain anti-seizure medications can speed up how quickly your liver processes and removes Verzenio from your body. This can lower Verzenio levels, affecting how well it works against breast cancer.

There’s no best choice for managing both seizures and cancer. It’s a balancing act, since everyone’s experiences with seizures and cancer are unique. An oncologist and a neurologist can help you find the best treatment approach for you.

6. Select antibiotics

Antibiotics treat infections caused by bacteria. Most of them don’t cause issues with Verzenio. But certain antibiotics can interact with it, including clarithromycin and erythromycin.

These antibiotics slow down the breakdown of Verzenio, causing it to build up in your body. This increases the risk of side effects such as nausea, diarrhea, and more.

Your prescriber should recommend an antibiotic that doesn’t interact with Verzenio. But if your antibiotic can’t be changed from clarithromycin or erythromycin, an oncologist may temporarily adjust your Verzenio dose. Alternatively, they may monitor you for side effects.

Antibiotics are usually taken for a short time. An oncologist will likely adjust your Verzenio dose after you complete your antibiotic course.

7. St. John’s wort

St. John's wort is an herbal supplement that some people take for depression and anxiety. It’s available over the counter. But it’s known to interact with many medications, including Verzenio.

St. John’s wort can speed up how quickly Verzenio is broken down in the liver. This can lower the amount of Verzenio in your body, affecting how well it works for breast cancer. Because of this risk, you shouldn’t take St. John’s wort while you’re taking Verzenio.

Tell your oncologist if you’re experiencing anxiety or depression symptoms. They can refer you to a psychiatrist or psychologist who can help you weigh safe and effective treatment options. Examples include prescription medications or cognitive behavioral therapy.

8. Certain stimulant medications

Modafinil and armodafinil are stimulant medications used for narcolepsy, obstructive sleep apnea, and shift work disorder. They can interact with Verzenio by speeding up its breakdown, potentially making it less effective.

If you take modafinil or armodafinil, tell your prescriber before starting Verzenio. They can determine if another treatment option would be a better choice.

Can you take vitamin D with Verzenio?

Yes, vitamin D isn’t known to interact with Verzenio. In fact, some people with breast cancer may be advised to take vitamin D to support bone health, especially if they’re also taking hormone therapy.

Still, tell your healthcare team about vitamins, supplements, or herbal products you take. Vitamin D isn’t expected to interact with Verzenio, but some supplements can. Your care team can help ensure everything you take is safe and appropriate for your treatment plan.

Can you drink coffee while taking Verzenio?

Yes, coffee isn’t known to interact with Verzenio. Most people can continue drinking coffee and other caffeinated beverages while taking it.

But Verzenio commonly causes diarrhea, which can increase your risk of dehydration. For some people, caffeine can also worsen diarrhea or upset the stomach. If you notice that coffee makes these side effects worse, consider cutting back or choosing decaf.

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Written by:

Mandeep Sohal, PharmD

Mandeep Sohal, PharmD, is a licensed pharmacist in California with over 7 years of experience. In his career, he’s worked in specialty and community pharmacy, pharmacy benefit management, and pharmaceutical manufacturers.

Edited by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

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