Imatinib (Gleevec)

Imatinib (pronounced [eye MAT eh nib]) is also known by the brand name, Gleevec. Imatinib is an antineoplastic (anti-cancer) drug that belongs to a class called BCR-ABL tyrosine kinase inhibitors. It is a type of chemotherapy that prevents cancer cells from multiplying and slows down their growth.

What Is Chemotherapy?

Chemotherapy is a cancer treatment in which certain drugs are used to kill cancerous cells. These drugs are usually cytotoxic chemical substances that are toxic to the cells, restrict their growth, prevent their division, and ultimately kill the cells. 

Protection From Chemotherapy

This drug is considered to be a hazardous agent, and normally, these pills are covered by a thin coating of material, but if this coating is damaged, removed, melted, or if the pill is broken into pieces, the chemical inside the pill can cause damage to your skin if you touch it. Therefore, it is important to take appropriate precautions for receiving, handling, storing, administering, and disposing of this medication. It is highly recommended to wear gloves if touching this medication or avoid touching it entirely by using the cap of the bottle to scoop up the tablet and put it directly into the mouth. 

How Is Imatinib Used?

Imatinib has been approved by the Food and Drug Administration (FDA) to treat chronic myeloid leukemia (CML), acute lymphoblastic leukemia (ALL), gastrointestinal tumors, and many other types of cancers as well as blood disorders. 

Available Formulations

Imatinib is available in the form of oral tablets only. The tablets are available in two different strengths: 100 mg and 400 mg. Typically, the dose should not exceed 600 mg daily and will depend on the type of disease being treated. The dose will also depend on whether you have other conditions, such as kidney or liver damage (the dose will be adjusted according to kidney or liver function).

Directions for Use

Imatinib is typically dosed once a day, ranging between 100 mg to 600 mg per dose, depending on cancer type and severity. Verify the correct dose and frequency with your provider. The dose should not be more or less than what is prescribed. 

Administer dose with a meal and a large glass of water. While taking the tablet, swallow it whole; do not break, crush, chew, or allow it to be dissolved in your mouth. Avoid skin contact with crushed tablets; if contact occurs, wash thoroughly.

Tablets may be dispersed in water or apple juice using: 

• 50 ml for a 100 mg tablet 
• 200 ml for a 400 mg tablet

Stir until the tablet dissolves and administer immediately. To ensure the full dose is administered, add more water to rinse the glass and administer. Do NOT disperse in grapefruit juice.

Imatinib tablets can be made into an oral suspension with Ora-Sweet. Shake the suspension well before use and be aware of the date of use. 

Missed Dose

If you miss a dose of this medicine, skip the missed dose and take your next dose when you normally would. Do not take extra medicine to make up for a missed dose.

Storage

Store tablets in a cool, dry place at room temperature and ensure the bottle is tightly closed. The oral suspension, once made, is stable for up to 14 days refrigerated or at room temperature.

What To Avoid While Taking Imatinib?

While taking imatinib therapy, you must follow some precautions. Always tell your physician about any medications you are already taking. Do not take any drug or medicine (even herbals, vitamins, or over-the-counter medications) without prior consent from your physician or pharmacist. They may have some significant interactions with imatinib. Avoid grapefruit, grapefruit juice, and any foods or supplements containing grapefruit or grapefruit juice throughout therapy as they may interact with the medication as well.

Pregnancy and Imatinib

Pregnancy status must be checked prior to starting imatinib therapy in women of childbearing age, and effective contraception must be used during treatment and for 2 weeks after the last dose. Imatinib may cause fetal harm and is therefore not recommended for women who are breastfeeding during therapy. Breastfeeding should also be avoided for at least 1 month after the last dose. 

Imatinib Side Effects

As with any other medication, you may encounter side effects while taking imatinib. A few things to remember are:

• You may not have all the side effects listed below. Many people may experience little to no side effects.
• The severity of side effects may vary from person to person, so don’t compare your side effects with other people’s experiences.
• Most of the side effects will improve when therapy is discontinued.
• These side effects are easily manageable most of the time, either by readjusting the dose of imatinib or using additional medications to treat the symptoms. Consult with your physician or pharmacist to explore available options.
• Do not hide any symptoms; if you feel any discomfort, do not hesitate to tell your physician or pharmacist about it.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions. 

Some of the more serious side effects of imatinib are listed below:

Hair Loss

One of the most conspicuous side effects of chemotherapy encountered is hair loss. This happens because most chemotherapies, including imatinib, act on rapidly dividing cancerous cells as well as healthy cells of the body like hair cells. However, the hair usually grows back once the chemotherapy is stopped. 

Liver Complications

In certain cases, imatinib can affect the liver and cause liver damage. The condition of the liver is monitored through blood tests that are able to detect liver function. Contact your physician immediately if you experience liver problems like dark urine, fatigue, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or yellow skin or eyes. These may be indications of liver complications.

Kidney Complications

Imatinib may cause kidney complications, leading to kidney dysfunction. Kidney status can be monitored by taking a urine test at the doctor’s office. Contact your physician if you are experiencing any inability to pass urine, changes in how much urine is passed, blood in the urine, or a sudden weight gain.

Bone Marrow Suppression (BMS)

It is essential to keep up with regular blood tests, especially the complete blood count test (CBC). The CBC blood test is capable of detecting BMS, including neutropenia (low neutrophils, a type of white blood cell), thrombocytopenia (low platelet count), and anemia (low red blood cells), all of which are potential side effects from the use of imatinib. BMS is typically prevalent within the first few months of starting therapy, which is why it is recommended to have a weekly CBC test for monitoring during the first few months. Consult with your physician for further details. 

Cardiac Complications

There may be cardiac complications with the use of imatinib, such as left ventricular dysfunction (LVD) or heart failure. Hypertension can be managed with antihypertensive therapy. Due to the severity of this side effect, regular monitoring of the heart is warranted through an echocardiogram (ECG) and blood tests. 

Fluid Retention

Imatinib can commonly cause fluid retention (also known as edema) and weight gain. Edema may lead to significant complications, including liver or heart complications and edema in the lungs. Rapid weight gain or swelling of the abdomen, legs, feet, or arms can all be signs of fluid retention. Contact your physician if you experience any of these symptoms. 

Dizziness/Drowsiness

Imatinib can cause dizziness, drowsiness, fatigue, feelings of tiredness, and blurred vision. Driving or operating heavy machinery while taking imatinib is not advised. 

GI Irritation or Bleeding

GI irritation like upset stomach or nausea may occur with imatinib use. Taking imatinib with food and water may help reduce GI irritation effects. Although rare, severe bleeding, including GI hemorrhage and tumor hemorrhage, is possible with Imatinib use. Contact your physician immediately if you experience vomiting or coughing blood; vomit that looks like coffee grounds; blood in urine; black, red, or tarry stools; bleeding from the gums; abnormal vaginal bleeding; bruises without a reason or that get bigger; or any severe or persistent bleeding.

Skin Rash

On rare occasions, Imatinib may cause a serious skin reaction called Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN). These rashes may appear as red, swollen, hives; itching, blistered, or peeling skin (with or without fever); red or irritated eyes; or sores in the mouth, throat, nose, or eyes. Notify your physician or pharmacist immediately of any signs of a rash or allergic reaction, including wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat. Discontinuation of imatinib should be warranted if SJS or TEN is suspected.

Tumor Lysis Syndrome (TLS)

TLS is caused by the rapid breakdown of cancer cells (bursting of the cells). TLS can cause you to have kidney failure with the need for dialysis treatment or an abnormal heart rhythm. Certain types of conditions are at higher risk for TLS. Consult with your physician to learn more. Tell your healthcare provider right away if you have any of the following signs or symptoms of TLS: trouble passing urine, abnormal heartbeat, passing out, muscle weakness or cramping, constant fatigue, diarrhea, or inability to eat.

Other common side effects may include:

• Gas
• Headache
• Dry skin
• Changes in taste
• Nose or throat irritation
• Back or joint pain
• Muscle spasm
• Weight gain 
• Anxiety
• Night sweats

Precautions

Extra monitoring may be necessary for certain patients.

• Kidney Failure: Patients are at a higher risk for kidney failure if they have other medical conditions such as:
  • Preexisting kidney complications
  • High blood pressure
  • Heart failure 
  • Diabetes
• Growth Impediment: Prepubescent children receiving imatinib are at high risk for growth delays in terms of decreased weight (decreased BMI) and delay in height growth. Growth should be monitored closely. Typically, once puberty is reached, normal growth patterns should be restored. 
• Fluid Retention (Edema): There is a higher risk for fluid retention if the patient is: 
  • Over 65 years old
  • Receiving high imatinib doses

FAQs

Is imatinib a chemo agent?

Chemo drugs are those that are used in the management of various cancers. Imatinib kills the cancer cells. Thus, it is a chemo agent that is advised as a treatment option for various cancer patients. 

How should imatinib be taken?

Administer dose with a meal and a large glass of water. While taking the tablet, swallow it whole; do not break, crush, chew, or allow it to be dissolved in your mouth. Tablets can be mixed in water or apple juice. Do NOT mix with grapefruit juice. Imatinib can also be made into an oral suspension with Ora-Sweet. Shake the suspension well before use and consume within 14 days. 

Can you lose your hair with imatinib?

Like other chemotherapeutic agents, imatinib has the potential to cause hair loss. 

Can you touch imatinib?

As stated earlier, chemo drugs contain chemicals that are hazardous to your health. Therefore, you should avoid touching them. It is recommended to wear gloves or pour the drug directly into the mouth using the cap of the container to avoid and minimize direct contact.