SIDE EFFECTS: See also Warning section. Diarrhea, headache, heartburn, mouth/throat sores, and trouble sleeping may occur. 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 hands/ankles/feet, sudden vision changes. Idelalisib can commonly cause a rash that is usually not serious. However, you may not be able to tell it apart from a rare rash that could be a sign of a severe reaction. Therefore, get medical help right away if you develop any rash. This medication can weaken the immune system/increase the risk of infection, including a rare but very serious (possibly fatal) brain infection (progressive multifocal leukoencephalopathy-PML). Get medical help right away if you have any of these side effects: clumsiness, loss of coordination/balance, weakness, sudden change in your thinking (such as confusion, difficulty concentrating, memory loss), difficulty talking/walking, seizure. 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 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 idelalisib, 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: liver disease, lung problems, stomach/intestinal ulcers, current serious infection. Idelalisib 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). Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while taking idelalisib. Idelalisib may harm an unborn baby. Women should ask about reliable forms of birth control while taking this medication and for 1 month after stopping treatment. Men should ask about reliable forms of birth control while taking this medication and for 3 months after stopping treatment. If you or your partner becomes pregnant, talk to your doctor right away about the risks and benefits of this medication. 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 tablets. It is unknown if this drug passes into breast milk. Because of the possible risk to the infant, breast-feeding while using this drug and for 1 month after stopping treatment 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 are: bendamustine, other drugs that weaken the immune system/increase the risk of infection (such as natalizumab, rituximab). Other medications can affect the removal of idelalisib from your body, which may affect how idelalisib works. Examples include rifampin, phenytoin, carbamazepine, St. John's wort, among others. This medication can slow down the removal of other medications from your body, which may affect how they work. Examples of affected drugs include domperidone, midazolam, 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.