Idelalisib (Oral)


Idelalisib is an anti-cancer drug that stops cancer cells from growing and spreading in the body.

It is combined with Rituxan (Rituximab) for the treatment of chronic lymphocytic leukemia that's relapsed.

Idelalisib also helps treat some kinds of lymphoma that haven't responded to certain treatments or those that have relapsed.

The FDA recently approved Idelalisib rather hurriedly. People in clinical studies showed a good response to this medication. However, it's not been proven that Idelalisib can lengthen survival time or improve symptoms.

This medicine is available as a tablet under the Zydelig brand name and is typically taken twice daily, with or without meals. Please don't break, divide, or chew Idelalisib tablets. Swallow them whole.

Common Idelalisib side effects include fever, diarrhea, nausea, fatigue, pneumonia, cough, rash, chills, and abdominal pain.

Idelalisib can also be taken for other purposes not mentioned in this medicine guide.

Conditions Treated

Type Of Medicine

  • Kinase inhibitor

Side Effects

In addition to its helpful effects, Idelalisib can cause some undesirable effects. While not all the effects below may happen, if they happen they may require medical intervention.

Please see your doctor at once if you develop any of these effects:

More common:

Clay colored stools


Body pain or aches

Tarry, black stools

Stomach or abdominal tenderness or pain



Dark urine

Cough producing mucus


Fast heartbeat


Ear congestion


Difficulty with breathing

Decreased appetite

Dark urine


Nausea and vomiting

Loss of voice

Loss of appetite


Skin rash or itching


Yellow eyes/skin

Bloody/watery diarrhea

Unusual tiredness/weakness

Unusual bleeding/bruising

White spots, sores, ulcers in the mouth

Troubled breathing

Tightness in chest

Swelling of the lower legs or feet

Runny/stuffy nose

Stomach cramps

Sore throat


Fast, shallow breathing

Pale skin

Difficult or painful urination

Tenderness or pain around the cheekbones and eyes

Less common:

Side pain or lower back pain

Constant urge to urinate

Difficult, painful, or burning urination

Cloudy/bloody urine

Bladder pain

Incidence unknown:

Chest pain

Loosening, peeling, or blistering of the skin




General feeling of illness or discomfort

Difficulty with swallowing

Cracks in skin

Vomiting of substance that bears a resemblance to coffee grounds, persistent and severe

Thickening of secretions from the bronchi

Severe stomach/abdominal pain, burning, or cramping

Scaly skin

Swollen, red skin

Red, irritated eyes

Red skin lesions, usually with a purple middle

Joint/muscle pain

Loss of body heart

Swelling or puffiness of eyelids, or around eyes, lips, face, or tongue

Some Idelalisib effects may develop that usually don't require medical intervention. These effects may clear during treatment while you get used to Idelalisib. Moreover, your healthcare specialist may recommend ways to reduce or prevent some of the effects. Please see your healthcare specialist at once if you have questions about these side effects, if they bother you, or if they don't go away.

More common:

Unusual weight loss or weight gain

Trouble sleeping

Tingling of the feet or hands

Rapid weight gain

Pain in joints

Night sweats

Muscle stiffness/pain

Difficulty with moving

Decreased appetite

Swelling or bloating of the feet, lower legs, hands, arms, or face

Some rare, but very serious Idelalisib side effects may occur. They include:

Colitis or severe diarrhea - diarrhea is quite common with Idelalisib treatment and may sometimes be very serious. Tell your healthcare specialist at once if you have up to 4-6 bowel movements in a day.

Liver problems - your healthcare specialist will carry out blood tests prior to and during your Idelalisib treatment to check if there are liver problems. Call up your healthcare specialist at once if you develop any of the symptoms of liver issues below:

Brown or dark urine

Bruising/bleeding more easily than normal

Pain in the right upper side of stomach area

Yellowing of skin or eyes (jaundice)

Breathing or lung problems (pneumonitis) - be sure to alert your healthcare specialist immediately if you have a worsening or new cough, wheezing, difficulty with breathing, or shortness of breath.

Perforation (tear in intestinal wall) - make sure to alert your healthcare professional and get treated at once if you have worsening or new stomach pain, fever, chills, vomiting, or nausea.

Not all Idelalisib side effects are mentioned above. Some of the rare ones (affecting less than 10 percent of patients) aren't listed above. However, be sure to always alert your healthcare specialist if you develop any abnormal symptoms.

Contact your healthcare specialist right away, whatever the time, if you experience any of the symptoms below:

Fever of 38 degrees Celsius or higher, or chills

Sudden onset of cough, shortness of breath, wheezing, or difficulty with breathing

Worsening or new stomach pain, fever, chills, vomiting, or nausea

The following Idelalisib symptoms require medical assistance, but aren't an emergency. Call up your healthcare specialist within 24 hours if you have any of these symptoms:

Decreased appetite

Itchy skin

Yellowing of whites of eyes or skin

Diarrhea (4-6 times in a day)

Nausea (interferes with your appetite and isn't relieved with prescribed medicine)

Peeling skin, rash, or blisters

Painful ulcers or sores on your lips, mouth, or skin

Fatigue that restricts normal day-to-day activities (such as bathing, showering, making meals and so on)

Signs of infection (including cough with/without mucus, burning with urination, nasal drainage, swelling or redness, and pus formation at incision or injury site)

Urine turns brown or dark (tea color)

Inability to drink or eat for a day or signs of dehydration such as thirst, dry mouth, tiredness, decreased amount of urine, dark urine, and dizziness

Always let your healthcare specialist know if you develop any unusual side effects.

Other Idelalisib side effects not mentioned or discussed above can also develop in some patients. Please consult with your healthcare specialist if you develop any other effects.


The dose of Idelalisib will vary with patients. Please follow the directions you see on the label or your doctor's orders. The following information only contains the standard doses of Idelalisib medication. If you have a different dose, don't adjust it unless your healthcare professional tells you otherwise.

The amount of Idelalisib medication you take is based on its strength. In addition, the total doses you have per day, the interval allowed between doses, as well as the duration in which you take Idelalisib depend on the condition for which you're taking Idelalisib.

For follicular B cell non-Hodgkin's lymphoma, small lymphocytic lymphoma, and chronic lymphocytic lymphoma, adults should begin with 150 milligrams per day. If necessary, your doctor may alter your dose. As for children, the dose and use must be decided by your doctor.

Medicines for treating cancer are really strong and may produce numerous side effects. Before you receive Idelalisib, ensure that you understand all its benefits and risks. It's vital for you to cooperate with your healthcare specialist during treatment.

Take Idelalisib exactly as instructed by your healthcare specialist. Don't take less or more of it, take it more times than prescribed, and take it beyond the prescribed period of time.

Idelalisib comes with a patient information leaflet (Medication Guide). Carefully read and stick to the instructions. If you've got any questions, ask your doctor.

Swallow the Idelalisib tablet whole. Don't chew, break, or crush it. You may take Idelalisib with or without your meals.

If you've missed a dose of Idelalisib, take it immediately once you remember. But if it's just about time for the next dose, revert to your normal dosing schedule and skip that missed dose. Don't take double doses of Idelalisib to compensate for missed ones.

If you've missed a dose of Idelalisib, you can still take it 6 hours after when you usually take it. But if it's beyond 6 hours, forget about the dose and revert to your usual dosing schedule.


Idelalisib may interact with any of the medications below:

  • Aripiprazole
  • Aprepitant
  • Bisoprolol
  • Bosentan
  • Amiodarone
  • Almotriptan
  • Calcitriol
  • Brentuximab
  • Cannabis
  • Deferasirox
  • Conivaptan
  • Brinzolamide
  • Buprenorphine
  • Carbamazepine
  • Bromocriptine
  • Buspirone
  • Colchicines
  • Disopyramide
  • Dofetilide
  • Disopyramide
  • Dofetilide
  • Dutasteride
  • Echinacea
  • Everolimus
  • Fingolimod
  • Domperidone
  • Dronedarone
  • Enzalutamide
  • Eplerenone
  • Denosumab
  • Drospirenone
  • Dantrolene
  • Eletriptan
  • Ethosuximide
  • Flutamide
  • Venlafaxine
  • Zolpidem
  • Guanfacine
  • Haloperidol
  • Lomitapide
  • Losartan
  • Tramadol
  • Trazodone
  • Leflunomide
  • Levomilnacipran
  • Lacosamide
  • Lidocaine
  • Maraviroc
  • Mefloquine
  • Mestranol
  • Methadone
  • Oxybutynin
  • Perampanel
  • Chloroquine
  • Cilostazol
  • Dapsone
  • Cyclosporine
  • Darifenacin
  • Zonisamide
  • Zopiclone
  • Trimethoprim
  • Ulipristal
  • Mifepristone
  • Mirtazapine
  • Nateglinide
  • Nefazodone
  • Modafinil
  • Montelukast
  • Ondansetron
  • Phenobarbital
  • Tocilizumab
  • Tolterodine
  • Pimecrolimus
  • Pimozide
  • Primidone
  • Primaquine
  • Ticlopidine
  • Tolvaptan
  • Prasugrel
  • Praziquantel
  • Quetiapine
  • Quinidine
  • Ramelton
  • Repaglinide
  • Quinine
  • Rifabutin
  • Eslicarbazepine
  • Sildenafil
  • Simeprevir
  • Tacrolimus
  • Temsirolimus
  • Rifampin
  • Rilpivirine
  • Romidepsin
  • St. John's wort
  • Theophylline
  • Ticagrelor
  • Roflumilast
  • Salmeterol
  • Teniposide
  • Tetracycline
  • Sirolimus
  • Solifenacin
  • Naloxegol
  • Phenytoin
  • Propafenone
  • Rivaroxaban
  • Tetrahydrocannabinol
  • Alpha blockers (Doxazosin, Alfuzosin, Tamsulosin, Silodosin)
  • Anti-cancer medications (Doxorubicin, Etoposide, Cabazitaxel, Docetaxel, Irinotecan, Vincristine, Ifosfamide)
  • Bacillus Calmette-Guérin/ (BCG)
  • Calcium Channel blockers (Diltiazem, Amlodipine, Verapamil, Nifedipine)
  • Azole antifungals (Ketoconazole, Itraconazole, Voriconazole)
  • Oral corticosteroids (Dexamethasone, Prednisone, Hydrocortisone)
  • Ergot-containing medications (Dihydroergotamine, Ergotamine, or Methysergide)
  • Benzodiazepines (Diazepam, Lorazepam Chlordiazepoxide, Clonazepam)
  • Inhaled corticosteroids (Fluticasone, Budesonide, Ciclesonide)
  • Estrogens (Conjugated Estrogen, Ethinyl Estradiol, Estradiol)
  • Gliptin diabetes medicines (Saxagliptin, Linagliptin, Sitagliptin)
  • Protease inhibitors of HIV (Saquinavir, Indinavir, Nelfinavir, Ritonavir, Atazanavir)
  • Protease inhibitors of hepatitis C (Telaprevir, Boceprevir, Simeprevir)
  • Macrolide antibiotics (Erythromycin, Clarithromycin)
  • Narcotic pain relievers (Oxycodone, Morphine, Codeine, Fentanyl)
  • Nitrates (Isosorbide Mononitrate, Isosorbide Dinitrate)
  • Tricyclic antibiotics (Trimipramine, Despiramine, Clomipramine, Amitriptyline)
  • Progestins (Norethindrone, Medroxyprogesterone, Levonorgestrel, Dienogest)
  • Proton pump inhibitor (Omeprazole, Lansoprazole)
  • Protein kinase inhibitors (Pazopanib, Nilotinib, Lapatinib, Imatinib, Erlotinib, Dasatinib, Bosutinib, Dabrafenib)
  • Phosphodiesterase 5 inhibitors (Vardenafil, Sildenafil, Tadalafil)
  • Statin anti-cholesterol medicines (Simvastatin, Lovastatin, Atorvastatin)
  • Selective serotonin-reuptake inhibitors (Fluoxetine, Duloxetine, Citalopram, Sertraline, Paroxetine)
  • HIV non-nucleoside reverse-transcriptase inhibitors (Nevirapine, Efavirenz, Delaviridine, Etravirine)

This isn't a full list of Idelalisib interactions. For more information about Idelalisib drug interactions, ask your pharmacist and doctor.

If you're using any of the above medications, consult your pharmacist and doctor first.


It is vitally important for your progress to be checked regularly by your doctor while you're taking Idelalisib (Zydelig). This will enable your doctor to determine if the medication is working well and to determine if you should keep taking the medication. You may require blood tests to check for adverse effects.

Using Idelalisib while you're expecting can put your unborn baby at risk. Please use an effective birth control method to avoid falling pregnant while you're taking Idelalisib and for around 1 month after you stop taking the medication. If you think you've gotten pregnant, make sure to notify your doctor promptly.

Idelalisib may bring on diarrhea, which may be severe in some cases. Before you take any medication to treat your diarrhea, check with your physician first. Diarrhea medications may make diarrhea persist or worsen. If you've got any queries about diarrhea or if your mild diarrhea gets worse or continues, see your doctor straight away.

Check with your healthcare professional at once if you have shortness of breath, cough, chest pain, or difficulty with breathing while you're using Idelalisib. In addition, alert your doctor at once if you have stomach or abdominal pain, fever, chills, vomiting, or nausea.

Serious skin reactions may occur after you use Idelalisib. See your doctor at once if you develop these symptoms while using Idelalisib: loose, peeling, or blistering skin, severe skin rash or acne, red skin lesions, or ulcers or sores on your skin.

This medication may bring on serious allergic reactions, for example anaphylaxis. Anaphylaxis is potentially fatal and will require urgent medical intervention. Please call up your doctor promptly if you develop itching, a rash, trouble swallowing, trouble breathing, or any kind of swelling of your face, mouth, or hands while you're taking Idelalisib.

Check with your physician if you develop any symptoms of sore throat, chills, or fever. These might be signs of an infection caused by neutropenia (a low level of white blood cells in your body).

Don't take other medications unless you've talked about them with your healthcare specialist. This includes non-prescription (over-the-counter) or prescription medications, as well as vitamin supplements and herbal products (including St John's Wort).


Keep Idelalisib in a sealed container, away from direct light, heat, and moisture. Remember to keep it at room temperature and out of children's reach.

Don't keep out of date medication or medication you no longer use. Ask your healthcare specialist how you should get rid of any medication you don't use.


If you're allergic to Idelalisib, please don't use it. To ensure that Idelalisib is safe to take, tell your healthcare professional if you have: lung disease, liver disease or an intestinal condition like ulcerative colitis.

Idelalisib may bring about serious or potentially fatal liver damage. Let your healthcare professional know if you've ever had liver disease or have it now. There may be an increased risk of damage in people using other medicines known to bring on liver damage, as well as in persons who already suffer with liver disease. Make sure to tell your pharmacist and doctor about the medicines you're using so they can find out whether any of the medications can increase your risk of developing liver damage while you're being treated with Idelalisib.

If you suffer any of these symptoms, call up your healthcare professional immediately: loss of appetite, extreme tiredness, weight loss, vomiting, nausea, unusual bruising/bleeding, pale stools, yellowing of eyes/skin, pain in the right upper area of the stomach, or brown or dark yellow urine.

Idelalisib may bring about severe or potentially fatal swelling of lungs (pneumonitis). Inform your healthcare specialist if you have breathing difficulties or lung disease. If you develop any of these symptoms, call up your doctor promptly: worsening or new cough, wheezing, shortness of breath, or difficulty with breathing.

Idelalisib may cause colitis (swelling of large intestine, also called colon), diarrhea, or perforation (holes) in the intestine or stomach. Let your healthcare provider know if you've ever suffered with colitis, if you have diarrhea, or if you have other disorders that affect your intestine or stomach. If you develop any of these symptoms, give your doctor a call right away: stomach pain or cramps, at least 6 bowel movements during the day, fever, chills, vomiting, or nausea.

Honor all of your doctor and lab appointments. Your doctor will arrange certain tests to assess your response to Idelalisib.

Don't allow anybody else to use your medicine. If you've got any queries about having your prescription refilled, ask your pharmacist.

Consult your doctor about drinking grapefruit juice and eating grapefruit while you're taking Idelalisib.

Discuss the risks of using Idelalisib with your doctor. Idelalisib can be prescribed for various other uses. For more details, ask your pharmacist and doctor.

Last Reviewed:
March 26, 2018
Last Updated:
April 26, 2018