SIDE EFFECTS: See also Warning section. Headache, nausea, vomiting, loss of appetite, constipation, diarrhea, cough, shortness of breath, dizziness, drowsiness, and tiredness may occur. In some cases, your doctor may prescribe medication to prevent or relieve nausea and vomiting. Eating several small meals, not eating before treatment, or limiting activity may help lessen some of these effects. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. People using this medication may have serious side effects. However, your doctor has prescribed this drug because he or she has judged that the benefit to you is greater than the risk of side effects. Careful monitoring by your doctor may decrease your risk. Tell your doctor right away if you have any serious side effects, including: easy bruising/bleeding, swelling ankles/feet. This medication can lower the body's ability to fight an infection. Tell your doctor promptly if you develop any signs of an infection such as fever, chills, or persistent sore throat. Nelarabine sometimes causes side effects due to the rapid destruction of cancer cells (tumor lysis syndrome). To lower your risk, your doctor may add a medication and tell you to drink plenty of fluids. Tell your doctor right away if you have symptoms such as: low back/side pain (flank pain), signs of kidney problems (such as painful urination, pink/bloody urine, change in the amount of urine), muscle spasms/weakness. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any of the following symptoms of a serious allergic reaction: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before using nelarabine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details. Before using this medication, tell your doctor or pharmacist your medical history, especially of: blood/bleeding disorders (e.g., anemia, low blood cell counts), kidney problems, liver disease, numbness/tingling in hands/feet (peripheral neuropathy), seizure. Do not have immunizations/vaccinations without the consent of your doctor, and avoid contact with people who have recently received oral polio vaccine or flu vaccine inhaled through the nose. Wash your hands well to prevent the spread of infections. Avoid contact with people who have illnesses that may spread to others (e.g., flu, chickenpox). To lower your risk of getting cut, bruised, or injured, use caution with sharp objects like razors and nail cutters, and avoid activities such as contact sports. Before having surgery, tell your doctor or dentist that you are using this medication. This drug may make you dizzy or drowsy. Alcohol or marijuana can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana. (See also Drug Interactions section.) Caution is advised when using this drug in older adults because they may be more sensitive to the effects of the drug, especially nervous system problems (e.g., numbness/tingling in hands/feet). This drug is not recommended for use during pregnancy. It may harm the unborn baby. Consult your doctor for details and to discuss the use of reliable forms of birth control while using this medication. If you become pregnant or think you may be pregnant, contact your doctor right away. It is not known whether this drug passes into breast milk. Because of the possible risk to the infant, breast-feeding while using this drug is not recommended. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. Some products that may interact with this drug include: other anti-cancer drugs (especially pentostatin). Tell your doctor or pharmacist if you are taking other products that cause drowsiness such as opioid pain or cough relievers (such as codeine, hydrocodone), alcohol, marijuana, drugs for sleep or anxiety (such as alprazolam, lorazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), or antihistamines (such as cetirizine, diphenhydramine). Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.

OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.