Neulasta (pegfilgrastim) is a brand-name injection that’s prescribed in certain situations to help your body make more white blood cells. Neulasta has interactions with some other drugs. Examples include chemotherapy.

Neulasta is prescribed for the following uses in adults and children:

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

Before you start treatment with Neulasta, 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 Neulasta interacts with supplements, herbs, or vitamins, see the “Neulasta and other interactions” section below.)

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

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

Drug class or drug nameDrug examplesInteraction result with Neulasta
chemotherapy• busulfan (Myleran)
• cyclophosphamide (Cytoxan)
• dacarbazine
• mitoxantrone
can make Neulasta less effective

In some cases, factors or conditions could prevent your doctor from prescribing Neulasta due to the risk of harm. These are known as contraindications. The contraindications of Neulasta include:

Having had an allergic reaction to Neulasta or any of its ingredients

If you’ve had an allergic reaction to Neulasta, any of its ingredients, or similar drugs such as filgrastim (Neupogen), your doctor will likely not prescribe Neulasta. Receiving the drug could cause another allergic reaction. You can ask them about other treatments that may be better choices for you.

Note: Before you start treatment with Neulasta, it’s important to tell your doctor if this contraindication applies. They can determine whether to prescribe Neulasta.

There are no known interactions between Neulasta and alcohol.

If you have questions about drinking alcohol while receiving Neulasta, talk with your doctor or pharmacist.

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

Chemotherapy

Neulasta can interact with chemotherapy, which is used to treat cancer. Neulasta is used to help reduce the risk of infection with chemotherapy. But it must be given at the right time in relation to your chemotherapy.

Interaction result: If you receive Neulasta 2 weeks before or 24 hours after receiving chemotherapy, Neulasta will be less effective at reducing your risk of infection.

Interaction explained: Chemotherapy can kill white blood cells. Neulasta works by helping your body make more white blood cells. White blood cells help your body fight infection. If you receive Neulasta and chemotherapy too close together, the chemotherapy will kill the new white blood cells that Neulasta helps your body make.

Examples of chemotherapy drugs: Here are some chemotherapy drugs that may interact with Neulasta:

  • busulfan (Myleran)
  • cyclophosphamide (Cytoxan)
  • dacarbazine
  • mitoxantrone

Steps you or your doctor may take: You should not receive Neulasta in the 14 days before and 24 hours after receiving chemotherapy.

To help prevent infections with chemotherapy, you’ll typically receive one dose of Neulasta with each cycle of chemotherapy. You’ll typically receive your Neulasta dose at least 24 hours after receiving the chemotherapy.

If you have questions about receiving Neulasta with chemotherapy, talk with your doctor or pharmacist.

Lithium

Neulasta may interact with lithium (Lithobid), which is a drug used to treat certain mental health conditions such as bipolar disorder.

Interaction result: Receiving Neulasta with lithium could make your white blood cell count get too high. This could cause serious side effects, such as heart attack, bleeding in your brain, or reduced blood flow to your limbs or brain.

Interaction explained: Neulasta helps your body make more white blood cells, so it increases your white blood cell levels. Lithium can also increase your white blood cell levels. Taking these drugs together could make your white blood cell levels get too high.

Steps you or your doctor may take: If you receive Neulasta with lithium, your doctor will frequently monitor your white blood cell levels.

If you have questions about receiving Neulasta with lithium, talk with your doctor or pharmacist.

Neulasta 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 Neulasta.

Neulasta and supplements

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

Neulasta and herbs

There are no specific reports of herbs interacting with Neulasta. 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 Neulasta treatment.

Neulasta and vitamins

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

Neulasta and food

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

Neulasta and vaccines

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

Neulasta and lab tests

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

NEULASTA INTERACTION WITH CANNABIS OR CBD

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

  • Myeloid cancers: If you have myeloid cancer (cancer affecting your bone marrow), your doctor will likely not prescribe Neulasta. Receiving the drug could cause your bone marrow to make more cancerous blood cells. Talk with your doctor about other treatments that may be better choices for you.
  • Breast or lung cancer: If you have breast or lung cancer, receiving Neulasta could raise your risk of blood cell cancers called myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Your doctor will monitor you closely for these cancers. If you have questions or concerns about this, talk with your doctor.
  • Sickle cell disease: If you have sickle cell disease, receiving Neulasta could cause a sickle cell crisis. (This occurs when red blood cells get stuck in your blood vessels, blocking blood supply to a part of your body. It can be fatal.) If you have sickle cell disease, talk with your doctor about whether Neulasta is right for you.
  • Allergic reaction: If you’ve had an allergic reaction to Neulasta, any of its ingredients, or similar drugs such as filgrastim (Neupogen), your doctor will likely not prescribe Neulasta. Receiving the drug could cause another allergic reaction. You can ask them about other treatments that may be better choices for you.
  • Allergy to acrylic adhesives: Neulasta comes in two forms: Neulasta and Neulasta Onpro. Neulasta Onpro comes with an on-body injector device that uses acrylic adhesive. If you’re allergic to acrylic adhesives, your doctor will likely not prescribe this form of Neulasta for you. It could cause an allergic reaction.
  • Breastfeeding: It’s not known whether it’s safe to use Neulasta while breastfeeding. There isn’t enough information to determine whether the drug passes into breast milk or what effects Neulasta may have on a child who is breastfed. If you’re breastfeeding or planning to, talk with your doctor before using Neulasta. 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 Neulasta is safe to use while pregnant. Animal studies show that the drug may cause 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 Neulasta. They can advise you on the right treatment plan for you.

You can take certain steps to help prevent interactions with Neulasta. 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 Neulasta 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 Neulasta 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 Neulasta 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.