How long is nelarabine (Arranon) treatment?

How long you take nelarabine (Arranon) can be different for each person. It depends on how well the medication works, your side effects, and if you can get a [bone marrow transplant](https://www.cancer.gov/about-cancer/treatment/types/stem-cell-transplant). Most people keep taking nelarabine (Arranon) as long as it’s helping and side effects are manageable. Your oncologist might decide to stop treatment if your cancer gets worse or if you become eligible for a transplant. Keep talking with your oncologist about how treatment is going and any side effects you have. They can discuss with you about how long you need nelarabine (Arranon).

Nelarabine

Generic Arranon

Used for Leukemia

Nelarabine (Arranon) is a type of chemotherapy known as an antimetabolite. It treats T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL). This medication is approved for adults and children with these blood cancers who’ve already tried other therapies. Nelarabine (Arranon) is given as an injection into the vein at an infusion center or medical office. It’s given on certain days during each 21-day treatment cycle. Side effects include nausea, tiredness, sleepiness, and dizziness. It can also cause low blood cell counts.

Reviewed by:

Allison Baxley, PharmD, BCOP

Cydnee Ng, PharmD

Last reviewed on March 4, 2026

What is Nelarabine (Arranon)?

What is Nelarabine (Arranon) used for?

Relapsed or refractory T-cell acute lymphoblastic leukemia (T-ALL) in adults and children 1 year of age and older
Relapsed or refractory T-cell lymphoblastic lymphoma (T-LBL) in adults and children 1 year of age and older

How Nelarabine (Arranon) works

Nelarabine (Arranon) is a type of chemotherapy called an antimetabolite. It works on fast-growing cells in the body, like cancer cells.

The medication looks like one of the normal building blocks of DNA. This allows it to get merged into the cell’s DNA. When this happens, the DNA can’t make copies of itself. It stops the cancer cell from growing and causes it to die so the cancer can’t grow or spread as well.

Drug facts

Common Brands	Arranon
Drug Class	Antimetabolite
Controlled Substance Classification	Not a controlled medication
Generic Status	No lower-cost generic available
Availability	Prescription only

Common Brands

Arranon

Drug Class

Antimetabolite

Controlled Substance Classification

Not a controlled medication

Generic Status

No lower-cost generic available

Availability

Prescription only

Side effects of Nelarabine (Arranon)

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

Anemia (low red blood cell count, 99%)
Low platelets (86%)
Low white blood cell counts (81%)
Tiredness (50%)
Nausea (41%)
Cough (25%)
Sleepiness (23%)
Fever (23%)
Diarrhea (22%)
Vomiting (22%)
Constipation (21%)
Dizziness (21%)
Shortness of breath (20%)
Headache (15%)

Less Common Side Effects

Numbness, tingling, or weakness in the arms or legs
Swelling of the arms, legs, or ankles
General weakness
Muscle weakness
Muscle, joint, or back pain
General pain
Swelling
Stomach pain
Low appetite
Mouth sores
Confusion
Trouble sleeping
Trouble walking
Shivering
Infection
Slow heart rate
Low blood pressure

Note: Side effects were reported by adults. Side effects in children can be slightly different.

Nelarabine (Arranon) serious side effects

Contact your healthcare provider immediately if you experience any of the following.

Serious side effects affecting the nervous system: extreme sleepiness, numbness or tingling, trouble talking, trouble walking, seizure, coma, paralysis
Serious infection: fever, chills, body aches, fast heartbeat, severe tiredness
Serious bleeding: unexpected bruising, bleeding that takes longer to stop, frequent nosebleeds, blood in urine or stool

When do Nelarabine (Arranon) possible side effects begin and end?

Time passed since treatment started:

HHOURS

DDAYS

WWEEKS

MMONTHS

Tiredness

Sleepiness

Dizziness

Headache

Numbness, tingling, or weakness in the arms or legs

Source: DailyMed

The following Nelarabine (Arranon) side effects have also been reported

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur:

More common

Abdominal or stomach pain or cramps

anxiety

black, tarry stools

bleeding gums

blood in the urine or stools

bloody nose

blurred vision

burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings

change in walking and balance

chest pain

chills

clumsiness or unsteadiness

cold sweats

coma

convulsions

cool, pale skin

cough or hoarseness

decreased or uncontrolled urination

difficulty with breathing

discouragement

dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position

drowsiness

dry mouth

fast or irregular heartbeat

feeling sad or empty

feeling unusually cold

fever

flushed, dry skin

fruit-like breath odor

headache

incoordination

increased hunger

increased thirst

increased urination

irritability

loss of appetite

loss of interest or pleasure

lower back, side, or stomach pain

mood or mental changes

muscle cramps in the hands, arms, feet, legs, or face

muscle pain

muscle spasms (tetany) or twitching

muscle weakness

nausea or vomiting

nervousness

nightmares

numbness, tingling, pain, or weakness in the hands, feet, fingertips, or mouth

pain or tenderness around the eyes and cheekbones

painful or difficult urination

pale skin

paralysis or severe weakness of the legs

pinpoint red spots on the skin

rapid breathing

seizures

shakiness and unsteady walk

shivering

sleepiness or unusual drowsiness

slurred speech

small red or purple spots on the skin

sneezing

sore throat

sores, ulcers, or white spots on the lips or in the mouth

stuffy or runny nose

sunken eyes

sweating

swelling of the hands, ankles, feet, or lower legs

swollen glands

tightness in the chest

trouble concentrating

trouble sleeping

troubled breathing with exertion

uncontrolled bowel movements

unexplained weight loss

unsteadiness, trembling, or other problems with muscle control or coordination

unusual bleeding or bruising

unusual tiredness or weakness

wrinkled skin

yellow eyes or skin

Less common

Change in taste

loss of memory

loss of taste

problems with memory

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Back pain

diarrhea

difficulty having a bowel movement (stool)

difficulty with moving

full or bloated feeling

joint pain

lack or loss of strength

muscle aching or stiffness

pain in the arms or legs

pressure in the stomach

swelling of the abdomen or stomach area

swelling or inflammation of the mouth

swollen joints

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Pros and cons of Nelarabine (Arranon)

Pros

Recommended treatment option for people with relapsed or refractory T-ALL
A treatment option for a very rare type of cancer, T-LBL
Less likely to cause hair loss than other chemotherapy

Cons

Need to go to an infusion center on certain days of each treatment cycle, so might not be convenient
Can cause nausea and sleepiness
Risk of nervous system problems, like tingling or weakness in the arms or legs

Pharmacist tips for Nelarabine (Arranon)

Follow the treatment plan your oncologist gives you. Nelarabine (Arranon) is given on certain days of each treatment cycle, and it can be easy to lose track of appointments. Using a calendar or a phone app for reminders can help you remember when your infusions and follow ups are.
Give yourself plenty of time for your nelarabine (Arranon) infusions. For adults, each infusion takes 2 hours, and for children, 1 hour. It’s a good idea to add some extra time to check in and get settled. Be sure to wear comfortable clothes and bring something to do to pass the time.
You can feel sleepy, tired, weak, or dizzy after your nelarabine (Arranon) infusion. This can sometimes last a few days after your infusion. Don’t drive or do anything that needs full attention until these side effects go away. If they make it hard to do your normal activities or don’t improve, talk to your care team.
Nelarabine (Arranon) can cause numbness or tingling in your fingers, hands, toes, or feet. It can also make it hard to coordinate movement, like buttoning clothing or walking. Sometimes, you might feel unsteady or weak when moving or going up stairs. If this happens, tell your care team so they can see how they can help you.
Nelarabine (Arranon) can often cause nausea and vomiting. Your oncologist can give you antiemetics like ondansetron (Zofran) to help. You can take these at home between infusions if you need to. If these side effects are severe or don’t get better with medications, talk to your care team.
Check your temperature regularly during your treatment with nelarabine (Arranon). Call your care right away if your temperature is 100.4ºF or higher. This means you have a fever, and it might be the only sign you’re sick. Fever is important to look out for because this medication can lower your white blood cell count and make it easier for you to get sick.
Before getting any vaccines, tell the healthcare professional that you’re taking nelarabine (Arranon). They can make sure the vaccine is safe for you. Avoid live vaccines during treatment. It’s not known how this medication affects your body’s response to them. Some live vaccines include MMR (the measles, mumps, and rubella vaccine) and FluMist (the nasal spray flu vaccine).
If you can become pregnant, use reliable birth control while taking nelarabine (Arranon). This medication might harm an unborn baby. If you get pregnant during treatment, tell your oncologist right away.
If you can father a child, use condoms while taking nelarabine (Arranon) and for 3 months after your last dose. This medication has a risk of harming an unborn baby. If your partner becomes pregnant during treatment, call your oncologist right away.

Common questions about Nelarabine

Yes, Nelarabine is a type of traditional chemotherapy. It works by stopping DNA in fast-growing cells, like cancer cells, from making copies of itself. This kills the cancer cells and stops the cancer from growing as well. But Nelarabine can also affect some normal, healthy cells in the body. That’s why the medication can cause some side effects, such as low blood cell counts and nausea.

You’ll need to go to an infusion clinic or cancer center to receive Nelarabine. This is because a trained healthcare professional must prepare the medication safely. And, a nurse will administer it as an infusion through your vein. You can’t pick up Nelarabine at a local or specialty pharmacy. Talk to your oncology team about scheduling your infusion appointments.

Take steps to avoid getting sick while taking Nelarabine. This medication can lower your white blood cell count, which can make it easier for you to get sick. Some infections can be serious. Try to stay away from large crowds and people who are sick. You can wear a mask for extra protection if you can’t avoid them. Don’t share toothbrushes, cups, or eating utensils with others. Also, avoid getting any live vaccines during treatment. It’s not known how Nelarabine affects how your body reacts to them. Ask a healthcare professional before getting any vaccines to make sure it’s safe for you. Talk to your oncology care team about other things to avoid during treatment.

How long you take Nelarabine can be different for each person. It depends on how well the medication works, your side effects, and if you can get a bone marrow transplant. Most people keep taking Nelarabine as long as it’s helping and side effects are manageable. Your oncologist might decide to stop treatment if your cancer gets worse or if you become eligible for a transplant. Keep talking with your oncologist about how treatment is going and any side effects you have. They can discuss with you about how long you need Nelarabine.

Hair loss isn’t a common side effect of Nelarabine. To help protect your hair, use a brush with soft bristles or a wide-tooth comb and wash with a mild shampoo. If you notice hair thinning or hair loss while taking this medication, tell your oncology care team. They can help find the cause and talk with you about your concerns.

No, don’t breastfeed while you’re taking Nelarabine. We don’t know if the medication can pass into breast milk. But there are possible risks to a nursing infant if it does. Talk to your oncologist or a lactation expert about safer feeding options.

Risks and warnings for Nelarabine (Arranon)

Nelarabine (Arranon) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

Serious side effects affecting the nervous system

Risk factors: Previous brain or spine radiation | Chemotherapy that’s given as an injection into the spinal fluid

Warning Icon Nelarabine (Arranon) can cause side effects affecting the nervous system. Most are mild and include tiredness, headache, dizziness, numbness, and weakness. But it’s possible for some to be severe and life-threatening. These can include extreme sleepiness, seizures, coma, trouble walking, and even paralysis. There have also been rare reports of symptoms similar to Guillain-Barré syndrome.

In studies, these side effects often started after the first infusion of nelarabine (Arranon). They can last a few days after and can also happen with later infusions. Sometimes, the side effects go away. But other times, they can last long term.

Your oncology care team will watch you closely for these nervous system side effects during treatment. If you notice any of these side effects at any time and they bother you, call your oncologist. Depending on how severe it is, you might have to stop taking nelarabine (Arranon). Get medical help right away if a serious side effect, like a seizure or loss of consciousness, happens.

Low blood cell counts

Nelarabine (Arranon) can cause low blood cell counts. A low red blood cell count can lead to symptoms like feeling more tired and anemia. In addition, a low platelet count can put you at risk for easy bleeding and bruising. And a low white blood cell count can make you more likely to get sick, which can sometimes be serious. You could also have a dangerous fever called febrile neutropenia.

During treatment, your oncologist will check your blood cell counts regularly with lab tests. If your counts are too low, your oncologist might delay your next dose of nelarabine (Arranon). Let your care team know if you have a fever, feel very tired, or have unexplained bruising or nosebleeds. Also tell them if you’ve gotten sick very often. These can be signs of low blood cell counts.

Tumor lysis syndrome

Some people taking nelarabine (Arranon) can be at risk of tumor lysis syndrome (TLS). This is a complication of treatment that happens when cancer cells break down very fast in the body. It can cause changes in your electrolyte levels, such as potassium and uric acid. This can lead to muscle cramps, kidney problems, abnormal heart rhythm if not treated.

To lower your risk of complications from TLS, your oncologist might give you extra fluids during treatment. They might also give you a medication called allopurinol (Zyloprim) to help manage uric acid levels.

Call your oncology care team right away if you have nausea, vomiting, low appetite, side pain, dark urine, or less urination. Also call them if you have muscle cramps or heart palpitations. These could be signs of TLS.

Avoid live vaccines during treatment

Avoid getting any live vaccines while taking nelarabine (Arranon). We don’t know if live vaccines are safe for you during treatment. These include MMR (the measles, mumps, and rubella vaccine), Varivax (the chickenpox vaccine), and FluMist (the nasal spray flu vaccine).

Before getting any vaccines, tell the healthcare professional you’re taking nelarabine (Arranon). They can make sure it’s okay for you to get it.

Harm to an unborn baby

Risk factors: Pregnancy

Based on animal studies and how it works, nelarabine (Arranon) might harm an unborn baby if used during pregnancy. If you can become pregnant, use effective birth control while taking this medication. If you can get someone else pregnant, use birth control like condoms while taking nelarabine (Arranon) and for 3 months after your last dose. If you or your partner gets pregnant, tell your oncologist right away.

Nelarabine (Arranon) dosage

Typical dosage for Nelarabine (Arranon)

Nelarabine (Arranon) is given as an infusion through a vein, or an intravenous (IV) infusion. It’s given by a trained healthcare professional at an infusion clinic or medical center.

Your oncologist will find the dose that’s right for you. It’s based on your body size or body surface area (BSA), which is calculated in m² units from your height and weight.

Adults: The typical dose is 1,500 mg/m² of BSA given as an IV infusion over 2 hours. It’s given on days 1, 3 and 5 of your treatment cycle, which gets repeated every 21 days.
Children: The typical dose is 650 mg/m² of BSA given as an IV infusion over 1 hour. It’s given once a day on days 1 to 5 of each treatment cycle, which gets repeated every 21 days.

Interactions between Nelarabine (Arranon) and other drugs

Nelarabine (Arranon) may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Nelarabine (Arranon). Please note that only the generic name of each medication is listed below.

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

Measles Virus Vaccine, Live
Mumps Virus Vaccine, Live
Rotavirus Vaccine, Live
Rubella Virus Vaccine, Live
Varicella Virus Vaccine, Live
Zoster Vaccine, Live

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.