What To Avoid When Taking Gleevec — Plus, 6 More Pharmacist-Backed Tips for Taking It

Gleevec (imatinib) was one of the first medications to change how oncologists treat cancer. The discovery of specific changes in a protein called BCR-ABL1 led to a new class of medications called targeted therapies.

Targeted therapy medications fight against specific pathways that lead to cancer growth. Prior to this, options really only included chemotherapy and radiation — treatments that can’t tell the difference between cancer and healthy cells. Gleevec blocks specific proteins that cause cancer growth. This allows people with certain blood and gastrointestinal cancers to live longer.

If you’ve been prescribed this pill, you’ll want to make sure you’re getting the most out of it. Here, we’ll discuss which medications to avoid, how to manage side effects, and other tips for maximizing your success with Gleevec.

EXPERT PICKS: WHAT TO READ NEXT

• How does Sprycel (dasatinib) compare? Read about the potential side effects of this Gleevec alternative.

• Food and drink interactions: Grapefruit isn’t the only food that has the potential to interact with your medications. Keep an eye out for these other dietary interactions.

• ‘Do not crush’ list: Learn about specific medication characteristics that prevent certain medications from being crushed.

1. What to avoid when taking Gleevec

Certain medications, foods, and medical conditions don’t play well with Gleevec. It’s best to avoid the following products and situations while you take it.

Grapefruit juice

An enzyme (protein) called CYP3A4 is in charge of breaking down Gleevec in the body. Grapefruit and grapefruit juice block this enzyme, causing Gleevec levels to build up. This increases the chance of having side effects. It’s best to avoid grapefruit products while you’re taking Gleevec.

Medications called CYP3A4 inhibitors also block this enzyme. Examples of strong CYP3A4 inhibitors include antifungals such as ketoconazole (Nizoral), antivirals such as ritonavir, and antibiotics such as clarithromycin (Biaxin XL). It’s often OK to continue taking these while also taking Gleevec, but your oncologist may opt to give you a lower Gleevec dose or closely monitor you for side effects.

CYP3A4 inducers

Medications called CYP3A4 inducers speed up CYP3A4 activity. This can cause Gleevec to break down too quickly, decreasing its effectiveness. Examples of strong CYP3A4 inducers include seizure medications such as phenytoin (Dilantin), antibiotics such as rifampin (Rifadin), and herbal supplements such as St. John’s wort.

It’s best to avoid taking CYP3A4 inducers with Gleevec. But this isn’t always possible. In this case, your oncologist may prescribe an increased Gleevec dose to make sure it’s still effective.

Warfarin

Gleevec can prevent other medications from being broken down, too. One of these medications is warfarin (Coumadin, Jantoven), a blood thinner used to prevent and treat blood clots. Warfarin is very sensitive to drug interactions. Too much warfarin can result in bleeding.

For this reason, it’s best to avoid warfarin while taking Gleevec. It’s better to use an alternative blood thinner, such as enoxaparin (Lovenox) or heparin.

It can be hard to keep track of all the possible interactions with Gleevec. Your oncologist or pharmacist will make sure it’s safe to take Gleevec with your other medications.

Pregnancy and breastfeeding

You shouldn’t take Gleevec while pregnant or breastfeeding. Gleevec can cause birth defects or loss of your baby (miscarriage) if you take it while pregnant.

If you’re able to have a baby, it’s important that you use effective birth control during treatment with Gleevec and for 2 weeks after stopping it. You should also avoid breastfeeding for at least 1 month after stopping Gleevec.

2. It’s best to take Gleevec with food

Taking Gleevec with food and a large glass of water can help prevent nausea. This is because Gleevec can irritate your stomach and cause nausea if you take it on an empty stomach. What’s more, in rare cases, Gleevec can cause holes in the gut called intestinal perforations. These allow stool to leak outside the gut and cause life-threatening infections. Food may help lessen this risk.

3. How to take Gleevec if swallowing pills is difficult

Many adults have trouble swallowing pills. You might be tempted to crush your tablet and put it in soft food, but this isn’t a good idea with Gleevec. Exposure to the crushed tablet can be harmful.

Instead, dissolve Gleevec in 50 mL to 100 mL of water or apple juice. How much liquid you use depends on your prescribed tablet strength; ask your pharmacist for specific recommendations. Once the tablet is fully dissolved, be sure to stir the liquid with a spoon and drink immediately.

If you don’t want to dissolve your tablet, there are other strategies to make swallowing easier. You can use the pop-bottle method, which uses the opening of a plastic bottle and the water inside to help you swallow pills. Tilting your chin to your chest before you swallow the tablet can also help. And don’t forget that you should always take Gleevec with a full glass of water to help wash it down.

4. There are ways to manage side effects from Gleevec

Gleevec side effects can make it difficult to take the medication regularly. Missing doses or having to temporarily stop taking Gleevec can impact how well it treats your cancer. Thankfully, there are strategies for combating side effects and minimizing missed doses.

Swelling

Gleevec can cause you to hold on to extra fluid, so swelling is a common side effect. It mostly occurs in the skin around the eyes but can also happen in the legs and face.

Swelling around the eyes is usually mild and gets better as the day goes on — it’s not a typical reason to stop Gleevec. However, sudden weight gain is a sign of too much fluid in the body, so it’s a good idea to weigh yourself regularly while taking imatinib.

If you experience rapid weight gain, severe swelling, or trouble breathing, reach out to your oncology team. They may prescribe diuretic medications to expel excess fluid and/or temporarily pause your Gleevec prescription.

Nausea

If taking Gleevec with food doesn’t prevent nausea, your oncologist may prescribe an antinausea medication such as ondansetron (Zofran). You can take ondansetron as soon as you experience nausea, but taking it 30 minutes before your Gleevec doses can also help. You can also try dietary changes — such as avoiding spicy foods; eating smaller, more frequent meals; and making sure you’re drinking enough water each day.

Diarrhea

Diarrhea is another common Gleevec side effect. Diarrhea is not only a nuisance, but it can also make you dehydrated and lead to kidney problems if it persists. 

You can treat diarrhea with an over-the-counter (OTC) medication, such as loperamide (Imodium A-D). Eating bland, low-fiber foods — such as saltine crackers, applesauce, and toast — can also help. It’s also important to stay well-hydrated by drinking plenty of clear liquids, such as electrolyte drinks, broth, and water.

Liver problems

Gleevec can mildly irritate the liver. To keep an eye on this, your oncologist should monitor your liver enzymes through regular blood draws. Elevated liver enzymes can be a signal of liver irritation or disease. Let your oncology team know if you have symptoms of liver problems, including yellowing of the skin, stomach pain, or dark urine.

Thyroid problems

Gleevec can cause low thyroid levels. This is especially true in people who have had their thyroid removed and need to take thyroid hormone replacement with levothyroxine (Synthroid). If you’re already taking levothyroxine when you start Gleevec, you’ll likely need a larger levothyroxine dose. Your oncology team should monitor your thyroid levels through regular blood draws and adjust your dose accordingly.

Low blood counts

Gleevec can lower your blood counts, including your white blood cells, red blood cells, and platelets. This increases your risk of infection, fatigue, and bleeding, respectively. Again, your oncologist should regularly monitor these changes through blood draws. If your counts drop too low, your oncologist may have you stop taking Gleevec for a bit and restart at a lower dose.

Rash

Skin rashes are another possible Gleevec side effect. They’re typically mild and can be managed with unscented moisturizers and topical corticosteroids. Avoiding hot showers and harsh soaps can also minimize itchiness.

Let your oncology team know if you have skin-blistering or peeling, or if your rash is growing. Gleevec could cause severe or life-threatening skin rashes that need immediate attention. 

5. What to do if you miss a dose of Gleevec

You might occasionally forget to take a dose of Gleevec. If this is the case, just skip the missed dose and take your next one at the normal time. You should never double up on your dose — this can be dangerous and cause unwanted side effects.

If you find you’re consistently missing doses, there are several creative ways to help you remember. These include medication reminder apps, phone alarms, and physical or digital calendars.

6. What to do if your child or pet accidentally swallows Gleevec

If your child accidentally swallows Gleevec, call your oncology office right away. If they’re not available, contact Poison Control online or at 1-800-222-1222. They can tell you if any next steps are necessary.

If your pet accidentally swallows Gleevec, contact your veterinary office or local emergency vet clinic. You can also call the American Society for the Prevention of Cruelty to Animals (ASPCA) Animal Poison Control Hotline at 1-888-426-4435 or the Pet Poison Helpline at 855-764-7661. You may have to pay a consultation fee.

7. How to store Gleevec

Keeping your medication out of reach of children and pets is the best way to prevent accidents. Gleevec should be stored at room temperature, so pick a cool, dry place that’s hard for pets and children to reach. A secure cabinet or high shelf should do the trick. Moisture isn’t good for medications, though, so avoid using the bathroom medicine cabinet. 

What’s more, make sure to keep Gleevec in its original container. These have child safety caps that are difficult for children to open. Putting Gleevec in pillboxes isn’t a good idea, because they’re not as secure.

Tips for saving on Gleevec

There are ways to save on Gleevec, which is available as a brand-name and generic product.

• Save with a copay savings card: If you have commercial insurance, you may be eligible to pay as little as $25 for brand-name Gleevec using a savings card from the manufacturer. You may also be able to pay as little as $0 for generic imatinib from Teva.

• Save with GoodRx: Generic imatinib’s price at certain pharmacies is as low as $39.90 with a free GoodRx discount. By comparison, the average cash price is roughly $8249.10.

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Written by:

Rachel Feaster, PharmD, BCOP, BCPS

Rachel Feaster has over 10 years of professional experience in ambulatory, inpatient, pharmacogenomics, and oncology care. She is board certified in oncology and pharmacotherapy.

Edited by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Reviewed by:

Vanessa Carranza, PharmD

Vanessa Carranza, PharmD, is a pharmacist who has dedicated her career to the advancement of medical education for healthcare providers, patients, and caregivers, most notably in the oncology space.

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