Idelalisib (Generic Name)

Other Names: Zydelig®

About This Drug  

Idelalisib is a drug used to treat cancer.  It is given by mouth.

Possible Side Effects (More Common)

  • Diarrhea (loose bowel movements 4 or more times a day or a loose bowel movement with weakness or a feeling of being dizzy)
  • Rash
  • Fever/Chills
  • Pneumonia
  • Change in liver function
  • Change in blood sugar level
  • Decrease in white blood cell count, which can raise your risk for infection

Possible Side Effects (Less Common)

  • Stomatitis (sores in the mouth)
  • Bronchitis
  • Muscle pain
  • Intestinal perforation

Treating Side Effects

  • Drink 6-8 cups of fluids each day unless your doctor has told you to limit your fluid intake due to some other health problem. A cup is 8 ounces of fluid. If you throw up or have loose bowel movements, you should drink more fluids so that you do not become dehydrated (lack water in the body from losing too much fluid).
  • For diarrhea that causes symptoms such as feeling dizzy or weakness, ask your doctor or nurse about medicine to help stop or lessen the loose bowel movements.
  • Your doctor will check your liver function tests, electrolytes, and blood sugar levels as needed.
  • Mouth care is very important.  Your mouth care should consist of routine, gentle cleaning of your teeth or dentures and rinsing of your mouth with a mixture of ½ teaspoon of salt in 8 ounces of water or ½ teaspoon of baking soda in 8 ounces of water.  This should be done at least after every meal and at bedtime.
  • If you have sores in your mouth, avoid mouthwash that has alcohol.  Also avoid alcohol and smoking because they can bother your mouth and throat.
  • If you get a rash, do not put anything on it unless your doctor or nurse says you may.  Keep the area around the rash clean and dry.  Ask your doctor for medicine if the rash bothers you. 
  • A rash that looks like acne may happen on your face and upper back while taking this medication.  Your doctor can give you medicine to help treat this.

Important Information

  • Take this medicine with water. Swallow it whole.  Do not chew, break or crush the tablet.
  • Missed dose:
    • If you miss a dose by less than 6 hours, take the missed dose right away.  Then take your next dose as usual. 
    • If you miss a dose by more than 6 hours, wait and take the next dose of the drug at your usual time.

Food and Drug Interactions

There are no known interactions of idelalisib with food. This drug may interact with other medicines. Tell your doctor and pharmacist about all the medicines and dietary supplements (vitamins, minerals, herbs and others) that you are taking at this time. The safety and use of dietary supplements and alternative diets are often not known. Using these might affect your cancer or interfere with your treatment. Until more is known, you should not use dietary supplements or alternative diets without your cancer doctor's help.

When to Call the Doctor

Call your doctor or nurse right away if you have any of these symptoms:

  • Shaking chills and/or fever of 100.5°F (38.0°C)
  • Rash or itching
  • Feeling dizzy or lightheaded
  • Loose bowel movements (diarrhea) more than 4 times a day or diarrhea with weakness or feeling lightheaded
  • Signs of liver problems:  dark urine, pale bowel movements, bad stomach pain, feeling tired and weak, unusual itching or yellowing of the eyes or skin
  • Severe abdominal pain

Call your doctor or nurse as soon as possible if any of these symptoms happen:

  • Pain in your mouth or throat that makes it hard to eat or drink
  • Rash that is not relieved by prescribed medicines

Reproduction Concerns

  • Pregnancy warning: This drug may have harmful effects on the unborn child, so effective methods of birth control should be used during your cancer treatment and for at least 4 weeks after your last dose of the drug.
  • Breast feeding warning: It is not known if this drug passes into breast milk.  For this reason, women should talk to their doctor about the risks and benefits of breast feeding during treatment with this drug because this drug may enter the breast milk and badly harm a breast feeding baby.

New: September 2014

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