This medication is used to treat a certain type of cancer (chronic lymphocytic leukemia-CLL). Idelalisib belongs to a class of drugs known as kinase inhibitors. It works by slowing or stopping the growth of cancer cells.

See also Warning section.

Read the Medication Guide provided by your pharmacist before you start taking idelalisib and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

Take this medication by mouth with or without food as directed by your doctor, usually twice daily. Swallow the tablets whole. Do not chew or crush the tablets.

The dosage is based on your medical condition and response to treatment. Do not increase your dose or use this drug more often or for longer than prescribed. Your condition will not improve any faster, and your risk of side effects will increase.

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.

See also Warning section.

Diarrhea, headache, heartburn, mouth/throat sores, and trouble sleeping may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

People using this medication may have serious side effects. However, you have been prescribed this drug because your doctor 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. 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.

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 make current infections worse. Stay away from anyone who has an infection that may easily spread (such as chickenpox, COVID-19, measles, flu). Talk to your doctor if you have been exposed to an infection or for more details.

Tell your health care professional that you are using idelalisib before having any immunizations/vaccinations. 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).

Older adults may be more sensitive to the side effects of this drug.

Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using idelalisib. Idelalisib may harm an unborn baby. Women using this medication should ask about reliable forms of birth control during treatment and for 1 month after the last dose. Men using this medication should ask about reliable forms of birth control during treatment and for 3 months after the last dose. 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, breastfeeding is not recommended while using this drug and for 1 month after the last dose. Consult your doctor before breastfeeding.

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 daridorexant, domperidone, elacestrant, finerenone, flibanserin, ivabradine, lurasidone, mavacamten, midazolam, pacritinib, sparsentan, triazolam, among others.

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 1-800-222-1222. Canada residents can call 1-844-764-7669.

Do not share this medication with others.

Lab and/or medical tests (such as liver function, complete blood count) should be done before you start taking this medication and while you are taking it. Keep all medical and lab appointments. Consult your doctor for more details.

If you miss a dose, take it as soon as you remember. If it is more than 6 hours after the missed dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store in the original container at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).