Idelalisib Side Effects

Medically reviewed by Philip Thornton, DipPharm. Last updated on Jan 2, 2025.

Applies to idelalisib: oral tablet.

Important warnings This medicine can cause some serious health issues

Oral route (tablet)

Serious hepatotoxicity, including fatalities, has been reported in 16% of patients administered idelalisib.

Fatal and/or serious diarrhea and colitis has also been reported in 20% of idelalisib patients.

Monitor hepatic function before and during treatment and monitor for the development of diarrhea or colitis.

Fatal and/or serious pneumonitis occurred in 4% of idelalisib patients.

Monitor for pulmonary symptoms and bilateral interstitial infiltrates.

Serious infections, including fatalities, have been reported in 48% of idelalisib patients.

Monitor for signs and symptoms of infection.

Fatal and serious intestinal perforation may occur.

Interrupt, reduce dose, or discontinue treatment with idelalisib as recommended.

Discontinue use if intestinal perforation occurs.

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:

More common side effects

• black, tarry stools
• body aches or pain
• chest tightness
• chills
• clay colored stools
• confusion
• cough
• cough producing mucus
• dark urine
• decreased appetite
• difficulty with breathing
• dizziness
• ear congestion
• fainting
• fast heartbeat
• fever
• headache
• itching or skin rash
• lightheadedness
• loss of appetite
• loss of voice
• lower back or side pain
• nausea and vomiting
• pain
• pain or tenderness around the eyes and cheekbones
• painful or difficult urination
• pale skin
• rapid, shallow breathing
• sneezing
• sore throat
• stomach cramps, pain, or tenderness
• stuffy or runny nose
• swelling of the feet or lower legs
• trouble breathing
• ulcers, sores, or white spots in the mouth
• unusual bleeding or bruising
• unusual tiredness or weakness
• watery or bloody diarrhea
• yellow eyes or skin

Less common side effects

• bladder pain
• bloody or cloudy urine
• difficult, burning, or painful urination
• frequent urge to urinate
• lower back or side pain

Incidence not known

• blistering, peeling, or loosening of the skin
• chest pain
• cracks in the skin
• difficulty with swallowing
• general feeling of discomfort or illness
• heartburn
• hives
• indigestion
• joint or muscle pain
• loss of heat from the body
• puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
• red skin lesions, often with a purple center
• red, irritated eyes
• red, swollen skin
• scaly skin
• severe abdominal or stomach pain, cramping, or burning
• thickening of bronchial secretions
• vomiting of material that looks like coffee grounds, severe and continuing

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:

More common side effects

• bloating or swelling of the face, arms, hands, lower legs, or feet
• decreased appetite
• difficulty with moving
• muscle pain or stiffness
• night sweats
• pain in the joints
• rapid weight gain
• tingling of the hands or feet
• trouble sleeping
• unusual weight gain or loss

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]

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