If you have certain cancers, your doctor might suggest Leukeran as a treatment option. It’s a prescription drug used to treat certain kinds of cancer in adults, including:

The active ingredient in Leukeran is chlorambucil. (An active ingredient is what makes a drug work.) It’s a kind of chemotherapy drug that comes as a 2-milligram (mg) tablet you swallow. (How many tablets you take will be determined by your doctor.) Depending on your situation, you may take this drug long-term.

For more information about Leukeran, including details about its uses, see this in-depth article.

Like other drugs, Leukeran can cause mild to serious side effects. Keep reading to learn more.

Some people may experience mild to serious side effects during their Leukeran treatment. Examples of commonly reported side effects include:

These are only some of the side effects Leukeran can cause. Read on to learn more about possible side effects of this drug.

* To learn more about this side effect, see the “Side effects explained” section below.

Mild side effects are not common with Leukeran, but they can occur.

Examples of mild side effects that have been reported with this drug include:

In most cases, these side effects should be temporary. And some may be easily managed. But if you have symptoms that are ongoing or bother you, talk with your doctor or pharmacist. And don’t stop taking this drug unless your doctor recommends it.

Leukeran may cause mild side effects other than those listed above. See the drug’s prescribing information for details.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Leukeran, visit MedWatch.

* To learn more about this side effect, see the “Side effects explained” section below.

Serious side effects can occur while taking Leukeran. Most are uncommon or rare, but certain side effects such as bone marrow suppression occurred more often in studies.

Serious side effects reported with Leukeran include:

If you develop serious side effects while taking Leukeran, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

* To learn more about this side effect, see the “Side effects explained” section below.
** Leukeran has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effects explained” section below.
† Leukeran has a boxed warning for this side effect. This is the most serious warning from the FDA. To learn more, see “Pregnancy and breastfeeding while taking Leukeran” under “Warnings for Leukeran” below.

Because Leukeran has not been studied in children, the drug’s safety and effectiveness for people ages 18 years and younger isn’t known. Because of this, the drug is not approved for use in children. But it’s sometimes prescribed off-label for children in certain conditions. (Off-label use is when a drug is prescribed to treat a condition other than those it’s approved for.)

Seizures are a reported side effect in children taking Leukeran, and this risk increases in those with nephrotic syndrome (symptoms from kidney problems). A history of head trauma or seizure disorders may also increase the risk of seizures.

If you have questions about Leukeran’s side effects in children, talk with your doctor.

Get answers below to some frequently asked questions about Leukeran’s side effects.

Are side effects more likely or severe with age?

Possibly. In studies, there was limited information on people ages 65 years and older taking Leukeran. So it’s not clear if older adults respond differently to Leukeran than younger adults.

Older adults may be more likely to have kidney or liver problems. They may also have other medical conditions and take other medications. These factors can increase the risk of side effects. For these reasons, the manufacturer of Leukeran recommends that older adults start with a lower dose of the drug.

How will my liver problems affect my risk of side effects?

Having liver problems can increase your risk of side effects from Leukeran. Studies haven’t been performed on people with liver damage taking this drug. So the extent to which liver problems can affect your risk of side effects isn’t known. But your liver removes Leukeran from your body, so if you have liver problems, the drug may build up in your system. And too much may cause side effects. Due to this risk, your doctor may start you at a lower dose of Leukeran if you have liver problems.

Liver damage is also a serious side effect of Leukeran. If you have any symptoms of liver damage during your treatment, tell your doctor right away. Symptoms include:

Before starting Leukeran, tell your doctor if you have any problems with your liver.

Learn more about some of the side effects Leukeran may cause.

Peripheral neuropathy

Peripheral neuropathy (nerve damage) is a possible side effect of Leukeran. It can also be caused by cancer. With peripheral neuropathy, the nerves connecting your brain and spinal cord to the rest of your body don’t work properly. If your peripheral neuropathy is caused by Leukeran, it may slowly decrease after your treatment ends. In some cases, it may never completely go away.

Examples of peripheral neuropathy symptoms include:

  • numbness, tingling, or prickling sensations (especially in the hands and feet)
  • increased pain from usually painless stimuli
  • sharp or burning pain
  • reduced sensations of temperatures or pain

What might help

If you start to have symptoms of peripheral neuropathy, tell your doctor. Depending on your situation, they may make changes to your treatment. They may also recommend certain pain medications or patches that can be applied to the skin to reduce pain in certain areas.

Massage, acupuncture, and physical or occupational therapies may help ease discomfort and improve balance, strength, and fine motor skills.

To ease the discomfort of peripheral neuropathy, try:

  • using a heating pad
  • applying an ice pack for 10 minutes twice daily to the affected areas
  • avoiding crossing your legs or other actions that increase pressure on the affected areas

Nausea and vomiting

Leukeran may cause nausea and vomiting. Other digestive problems include diarrhea and mouth sores. But overall, digestive problems didn’t occur often in the drug’s studies.

What might help

To help reduce the discomfort of nausea:

  • avoid strong odors
  • eat small, frequent meals
  • avoid high fat, spicy, or greasy foods

To help prevent vomiting, try sipping clear liquids and eating plain foods such as rice or crackers. And drink plenty of water or sports drinks to help you stay hydrated.

If your nausea and vomiting don’t go away or get worse, talk with your doctor. They may be able to provide more recommendations for relief.

Lung problems

Leukeran can cause pulmonary fibrosis where the lung tissue scars, making the lungs stiff. This can make it hard to breathe.

Symptoms of lung problems include:

What might help

Talk with your doctor if you have wheezing, coughing, or trouble breathing. A checkup can help them determine if you’re having lung problems.

Risk of cancer

Leukeran has a boxed warning for the increased risk of certain kinds of cancer. Boxed warnings are the most serious warnings from the Food and Drug Administration (FDA). They alert doctors and patients about drug effects that may be dangerous.

There are reports of leukemia in people being treated with Leukeran for cancers other than chronic lymphocytic leukemia (CLL) or lymphoma. And chlorambucil (the active drug in Leukeran) has been linked to an increased risk of acute myeloid leukemia. In many cases, the affected people were also being treated with other cancer drugs or radiation therapy.

The risk of other cancers is thought to increase with high doses of Leukeran or use of the drug over a long period of time.

Due to cancer risks, doctors usually will not prescribe Leukeran for cancers other than those it’s approved to treat. If you have cancers other than CLL or certain kinds of lymphoma, your doctor will consider these before treating you with this drug.

What might help

Before starting Leukeran, talk with your doctor about the benefits and risks of this drug for your particular situation.

During your treatment, call your doctor right away if you develop any symptoms of leukemia, such as:

Risk of bone marrow suppression

Leukeran has a boxed warning for the risk of bone marrow suppression. Boxed warnings are the most serious warnings from the Food and Drug Administration (FDA). They alert doctors and patients about drug effects that may be dangerous.

Bone marrow suppression is a common side effect of Leukeran. It’s usually reversible if caught early enough during treatment.

Red blood cells, white blood cells, and platelets are made from cells in your bone marrow. If your bone marrow’s ability to make new blood cells decreases, blood disorders can occur. Low levels of certain kinds of blood cells can increase the risk of anemia (low level of red blood cells) and infection. You can also bleed or bruise more easily.

What might help

If you notice symptoms of blood disorders that could be a sign of bone marrow suppression, call your doctor right away. Symptoms include:

Your doctor will check your blood counts often during your Leukeran treatment. Talk with them if you have questions or concerns about bone marrow suppression or blood disorders from this drug.

Allergic reaction

Like most drugs, Leukeran can cause an allergic reaction in some people. Symptoms can be mild to serious and can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, usually in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms. Examples include:

  • an over-the-counter oral antihistamine, such as Benadryl (diphenhydramine)
  • a topical product, such as hydrocortisone cream

If your doctor confirms you’ve had a mild allergic reaction to Leukeran, they’ll decide if you should continue using it.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to Leukeran, they may have you switch to a different treatment.

Keeping track of side effects

During your Leukeran treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start taking new drugs or using a combination of treatments.

Your side effect notes can include things such as:

  • what dose of the drug you were taking when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how it affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help them learn more about how Leukeran affects you. They can then use this information to adjust your treatment plan if needed.

Leukeran comes with multiple warnings.

Boxed warnings

Leukeran has boxed warnings about the risks of cancer, bone marrow suppression, fetal harm, and infertility. Boxed warnings are the most serious warnings from the Food and Drug Administration (FDA). They alert doctors and patients about drug effects that may be dangerous.

  • Risk of cancer. Leukeran may increase your risk of other cancers. Due to this risk, it’s only approved to treat certain cancers.
  • Risk of bone marrow suppression. Leukeran can decrease the ability of your bone marrow to produce blood cells, which can cause blood disorders.
  • Risk of fetal harm. Developing fetuses may be harmed if Leukeran is taken during pregnancy. Due to this risk, your doctor will likely recommend a different treatment other than Leukeran if you’re pregnant or become pregnant during treatment.
  • Risk of infertility. Leukeran may cause temporary or permanent infertility in both males* and females.*

For details about Leukeran’s risk of cancer and bone marrow suppression, see the “Side effects explained” section above. For information about Leukeran’s risk of fetal harm and infertility, see “Pregnancy and breastfeeding while taking Leukeran” below.

* In this article, we use the terms “male” and “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

Other warnings

Leukeran may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before starting Leukeran. Below are several factors to consider.

Seizure. Some people may have seizures when taking Leukeran. This risk increases if you have a history of seizures, head trauma, or take other drugs that can cause seizures. The seizure risk can also increase if you receive high pulse doses (a type of treatment schedule) of Leukeran. Due to this risk, your doctor will either monitor you more closely during your treatment or choose a different drug for you.

Allergic reaction. If you’ve had an allergic reaction to Leukeran or any of its ingredients, your doctor will likely not prescribe it for you. Ask them about other medications that might be better treatment options.

Recent therapy with radiation. Bone marrow suppression is a common side effect of Leukeran. It’s also a side effect of radiation therapy. Treatment with these therapies too close to each other can be dangerous. Due to this risk, doctors will likely prescribe Leukeran 4 weeks after your radiation therapy.

Low blood counts. Leukeran can cause a temporary decrease in your blood cells and platelets. This can increase your risk of infection, anemia, and bleeding.

Liver problems. This drug can cause a temporary increase in liver function tests. If you already have liver problems, your doctor will likely prescribe a lower dose of Leukeran for you. They’ll also order frequent tests during your treatment to monitor your liver enzyme levels.

Alcohol use and Leukeran

Leukeran’s interaction with alcohol is not known. Side effects such as nausea and vomiting may be increased if you drink while taking this drug.

Seizures and peripheral neuropathy are possible side effects of Leukeran. They can also occur from drinking large amounts of alcohol. Using the two together may increase the risk of these effects.

If you drink alcohol, talk with your doctor to learn more about how much, if any, is safe to consume during your Leukeran treatment.

Pregnancy and breastfeeding while taking Leukeran

See below for details about Leukeran’s effects on pregnancy, breastfeeding, and infertility.

Pregnancy

You should not take Leukeran during pregnancy. This drug has a boxed warning for the risk of fetal harm if taken while pregnant. This is the most serious warning by the Food and Drug Administration (FDA).

Your doctor can tell you more about the effects of Leukeran during pregnancy and can recommend birth control options.

Breastfeeding

It’s not known if Leukeran can pass through human breast milk. But the drug could cause risks to a breastfed child if it does. Your doctor will likely recommend you do not take Leukeran while you’re breastfeeding.

Risk of infertility

This drug has a boxed warning for the risk of infertility. This is the most serious warning by the Food and Drug Administration (FDA). Temporary or permanent infertility in both males* and females* may be caused by Leukeran.

* In this article, we use the terms “male” and “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

Leukeran can cause mild to serious side effects. Talk with your doctor before starting treatment. Ask questions to help you feel more comfortable about side effects the drug may cause. Some examples to get you started are:

  • What serious side effect is the most common?
  • If Leukeran treats cancer, why is cancer a side effect?
  • If I have severe side effects, does that mean Leukeran is not working well for me?
  • Does having kidney problems increase my risk of side effects?

Q:

Is hair loss a side effect of Leukeran since it’s a chemotherapy drug?

Anonymous

A:

In studies, hair loss was not a reported side effect of Leukeran. Not all chemotherapy drugs cause hair loss. And how severe your hair loss is with certain chemotherapy drugs depends on several factors, such as the kind of drug and each individual’s situation.

Some chemotherapy drugs damage healthy cells while they work to kill fast-growing cancer cells. Damage to typical, fast-growing hair follicle cells can cause hair loss.

Leukeran belongs to a group of drugs called alkylating agents. These drugs work to kill cancer cells in a different way than other drugs that target fast-growing cells. This difference between these two types of drugs may be what causes reduced hair loss with Leukeran.

If you have hair loss during your treatment with this drug, talk with your doctor.

The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

Disclaimer: Healthline 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.