Idelalisib Side Effects

Medically reviewed by Philip Thornton, DipPharm. Last updated on Jan 22, 2025.

Applies to idelalisib: oral tablet.

Precautions

It is very important that your doctor check your progress at regular visits while you are using this medicine. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to use it. Blood tests may be needed to check for unwanted effects.

Using this medicine while you are pregnant can harm your unborn baby. If you are a woman who can get pregnant, your doctor may do tests to make sure you are not pregnant before starting treatment. Female patients should use effective birth control during treatment with this medicine and for at least 1 month after the last dose. Male patients who have female partners should use effective birth control during treatment with this medicine and for at least 3 months after the last dose. If you think you have become pregnant while using this medicine, tell your doctor right away.

Idelalisib may lower the number of some types of blood cells in your body. Because of this, you may bleed or get infections more easily. To help with these problems, avoid being near people who are sick or have infections. Wash your hands often. Stay away from rough sports or other situations where you could be bruised, cut, or injured. Brush and floss your teeth gently. Be careful when using sharp objects, including razors and fingernail clippers.

Idelalisib may cause diarrhea, and in some cases it can be severe. Do not take any medicine to treat diarrhea without first checking with your doctor. Diarrhea medicines may make the diarrhea worse or make it last longer. If you have any questions about this or if mild diarrhea continues or gets worse, check with your doctor.

This medicine may cause serious infections (eg, pneumonia, sepsis). Check with your doctor right away if you have chest pain or tightness, cough, fever or chills, confusion, dizziness, lightheadedness, or fainting, fast heartbeat, sneezing, or trouble breathing.

Tell your doctor right away if you have a cough, trouble breathing, chest tightness, or any type of breathing problem with this medicine. These could be symptoms of a serious lung problem called pneumonitis.

Serious skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis can occur with this medicine. Check with your doctor right away if you have blistering, peeling, or loosening of the skin, chills, cough, diarrhea, itching, joint or muscle pain, red irritated eyes, red skin lesions, often with a purple center, sore throat, sores, ulcers, or white spots in the mouth or on the lips, or unusual tiredness or weakness while you are using this medicine.

This medicine may cause serious allergic reactions, including anaphylaxis, which can be life-threatening and requires immediate medical attention. Call your doctor right away if you have a rash, itching, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth while you are using this medicine.

This medicine may cause serious bowel problems, including perforation (hole). Check with your doctor right away if you have black, tarry stools, diarrhea, fever, severe vomiting, sometimes with blood, or stomach cramps or pain.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Serious side effects of idelalisib

Along with its needed effects, idelalisib 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 immediately if any of the following side effects occur while taking idelalisib:

Other side effects of idelalisib

Some side effects of idelalisib 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:

For healthcare professionals

Applies to idelalisib: oral tablet.

General adverse events

The most commonly occurring adverse reactions were pneumonia, pyrexia, sepsis, febrile neutropenia, cough, abdominal pain, chills, rash, fatigue, and diarrhea.^[Ref]

Hepatic

• Very common (10% or more): Increased ALT (up to 50%), increased AST (up to 41%), increased GGT (up to 26%)^[Ref]

Gastrointestinal

• Very common (10% or more): Diarrhea (up to 47%), nausea (up to 29%), abdominal pain (up to 26%), vomiting (up to 15%)
• Common (1% to 10%): Gastroesophageal reflux disease, stomatitis^[Ref]

Respiratory

• Very common (10% or more): Cough (up to 29%), pneumonia (up to 25%), dyspnea (up to 17%), upper respiratory tract infection (up to 12%)
• Common (1% to 10%): Nasal congestion^[Ref]

Hematologic

• Very common (10% or more): Decreased neutrophils (up to 60%), decreased hemoglobin (up to 28%), decreased platelets (up to 26%), increased lymphocytes (up to 25%), decreased lymphocytes (up to 20%)^[Ref]

Metabolic

• Very common (10% or more): Hypertriglyceridemia (up to 56%), hyperglycemia (up to 54%), hyponatremia (up to 20%), decreased appetite (up to 16%), hypoglycemia (up to 11%)^[Ref]

Other

• Very common (10% or more): Pyrexia (up to 35%), fatigue (up to 30%), chills (up to 21%), asthenia (up to 12%), peripheral edema (up to 10%)
• Common (1% to 10%): Pain^[Ref]

Immunologic

• Common (1% to 10%): Sepsis, bronchitis, sinusitis, urinary tract infection^[Ref]

Dermatologic

• Very common (10% or more): Rash (up to 21%), night sweats (up to 12%)^[Ref]

Musculoskeletal

• Common (1% to 10%): Arthralgia^[Ref]

Nervous system

• Very common (10% or more): Headache (up to 11%)^[Ref]

Psychiatric

• Very common (10% or more): Insomnia (up to 12%)^[Ref]

See also:

Frequently asked questions

• What is Zydelig used for and how does it work?

Further information

Idelalisib side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer