SIDE EFFECTS: Upset stomach, diarrhea, nausea, vomiting, decreased appetite, headache, joint/muscle pain, swelling of ankles/legs/feet, numbness/tingling of arms/legs, anxiety, constipation, dizziness, or tiredness may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. This medication may raise your blood pressure. Check your blood pressure regularly and tell your doctor if the results are high. Your doctor may control your blood pressure with medication. Tell your doctor right away if you have any serious side effects, including: easy bruising/bleeding, dark/tarry/bloody stools, fast/irregular/pounding heartbeat, signs of low red blood cell count (such as rapid breathing, pale skin, shortness of breath). Ibrutinib 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. This medication may lower your ability to fight infections. This may make you more likely to get a serious (rarely fatal) infection or make any infection you have worse. Tell your doctor right away if you have any signs of infection (such as fever, chills, persistent sore throat, cough). Very rarely, people taking this medication have developed other cancers (including skin cancer). Consult your doctor for more details. Get medical help right away if you have any very serious side effects, including: chest pain, signs of bleeding in the brain (such as fainting, sudden vision changes, severe nausea, seizures, confusion). A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: 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 any 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 taking ibrutinib, 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 problems, heart problems (such as fast/irregular heartbeat, previous heart attack), high blood pressure, kidney problems, liver problems, high levels of uric acid in the blood. This drug may make you dizzy. Alcohol or marijuana can make you more dizzy. 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. Ibrutinib can make you more likely to get infections or may worsen any current infections. Therefore, wash your hands well to prevent the spread of infection. Avoid contact with people who have infections that may spread to others (such as chickenpox, measles, flu). Consult your doctor if you have been exposed to an infection or for more details. Do not have immunizations/vaccinations without the consent of your doctor. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose). To lower the chance 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 about all the products you use (including prescription drugs, nonprescription drugs, and herbal products). Your doctor may tell you to temporarily stop treatment with this medication before certain medical, surgical, or dental procedures. Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the capsules. Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while you are taking ibrutinib. Ibrutinib may harm an unborn baby. Men and women should ask about reliable forms of birth control while taking this medication and for 1 month after stopping treatment. If you become pregnant, talk to your doctor right away about the risks and benefits of this medication. See also Notes section. It is unknown if 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: See also How to Use section. 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 are: other drugs that can cause bleeding/bruising (such as antiplatelet drugs like clopidogrel, NSAIDs like ibuprofen/naproxen, "blood thinners" like warfarin/dabigatran). Aspirin can increase the risk of bleeding when used with this medication. However, if your doctor has directed you to take low-dose aspirin for heart attack or stroke prevention (usually at dosages of 81-325 milligrams a day), you should continue taking it unless your doctor instructs you otherwise. Ask your doctor or pharmacist for more details. Other medications can affect the removal of ibrutinib from your body, which may affect how ibrutinib works. Examples include azole antifungals (such as itraconazole, ketoconazole), boceprevir, nefazodone, St. John's wort, telaprevir, HIV protease inhibitors (such as ritonavir, saquinavir), macrolide antibiotics (such as erythromycin, clarithromycin), rifamycins (such as rifampin, rifabutin), certain drugs used to treat seizures (such as carbamazepine, phenytoin), among others.

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.