Afatinib belongs to a class of drugs known as tyrosine kinase inhibitors. Tyrosine kinase inhibitors are designed to block the action of a specific enzyme called tyrosine kinase. This enzyme plays a big role in the function of cells, and is active in cancer cells to promote tumor growth and progression. Afatinib works to inhibit the function of two types of tyrosine kinases: epidermal growth factor receptor (EGFR) and Her2, which are "over-expressed" by several types of cancer. By blocking the function of these tyrosine kinases, Afatinib may prevent cancer cells from dividing and growing.
Afatinib works in tumors with specific abnormalities in EGFR and your healthcare provider will have your tumor tested for these abnormalities before prescribing this medication.
How to Take Afatinib
Afatinib comes as a tablet to take by mouth. It should be taken on an empty stomach, at least 1 hour before or 2 hours after eating a meal or snack. Take afatinib at around the same time every day. If you miss a dose, take it as soon as you remember. If it is within 12 hours of your next scheduled dose, skip the missed dose and take the next dose at your regular time. Do not take 2 doses to make up for the missed dose. Certain medications and supplements can interfere with how afatinib works, so be sure to tell your healthcare team about all medications, vitamins and supplements you are taking.
Possible Side Effects of Afatinib
There are a number of things you can do to manage the side effects of Afatinib. Talk to your doctor or nurse about these recommendations. They can help you decide what will work best for you. These are some of the most common side effects:
Nail and Skin Changes
Afatinib has some unique nail and skin side effects that you may develop. Patients may develop a rash. While this rash may look like acne, it is not, and should not be treated with acne medications. The rash may appear red, swollen, crusty and dry and feel sore. You may also develop very dry skin, which may crack, be itchy or become flaky or scaly. The rash typically starts in the first week of treatment, but can occur at any time during treatment. Tips for managing your skin include:
While receiving afatinib, you may develop an inflammation of the skin around the nail bed/cuticle areas of toes or fingers, which is called paronychia. It can appear red, swollen or pus filled. Nails may develop "ridges" in them or fall off. You may also develop cuts or cracks that look like small paper cuts in the skin on your toes, fingers or knuckles. These side effects may appear several months after starting treatment, but can last for many months after treatment stops.
Afatinib can cause diarrhea that can become severe, lead to dehydration and even death. Notify your oncology team right away if you experience diarrhea. They can recommend medications to relieve diarrhea. In addition to medications, try eating low-fiber, bland foods, such as white rice and boiled or baked chicken. Avoid raw fruits, vegetables, whole grain breads, cereals and seeds. Soluble fiber is found in some foods that absorbs fluid and can help relieve diarrhea. Foods high in soluble fiber include: applesauce, bananas (ripe), canned fruit, oranges, boiled potatoes, white rice and products made with white flour, oatmeal, cream of rice, cream of wheat, and farina. Drink 8-10 glasses on non-alcoholic, un-caffeinated fluid a day to prevent dehydration. Read Low Fiber Diet for Diarrhea for more tips.
While receiving afatinib, some patients may develop irritation or damage to the cornea (clear part covers the eyeball) or changes in your eyesight. Notify your healthcare team if you develop any eye pain, swelling, redness or any vision changes, including blurriness and sensitivity to light.
Nausea and/or Vomiting
Take anti-nausea medications as prescribed. If you continue to have nausea or vomiting, notify your doctor or nurse so they can help you manage this side effect. In addition, dietary changes may help. Avoid things that may worsen the symptoms, such as heavy or greasy/fatty, spicy or acidic foods (lemons, tomatoes, oranges). Try antacids, (e.g. milk of magnesia, calcium tablets such as Tums), saltines, or ginger ale to lessen symptoms. Read the Nausea & Vomiting Tip Sheet for more suggestions.
Call your doctor or nurse if you are unable to keep fluids down for more than 12 hours or if you feel lightheaded or dizzy at any time.
Exposure of an unborn child to this medication could cause birth defects, so you should not become pregnant or father a child while on this medication or for 2 weeks following the last dose of afatinib. Effective birth control is necessary during treatment, even if your menstrual cycle stops or you believe your sperm is affected. Afatinib can also be passed through breast milk, therefore women should not breast feed while using this medication.
While on cancer treatment you may need to adjust your schedule to manage fatigue. Plan times to rest during the day and conserve energy for more important activities. Exercise can help combat fatigue; a simple daily walk with a friend can help. Talk to your healthcare team and see OncoLink's section on fatigue for helpful tips on dealing with this side effect.
Mouth Ulcers (Sores)
Certain cancer treatments can cause sores or soreness in your mouth and/or throat. Notify your doctor or nurse if your mouth, tongue, inside of your cheek or throat becomes white, ulcerated or painful. Performing regular mouth care can help prevent or manage mouth sores. If mouth sores become painful, your doctor or nurse can recommend a pain reliever.
Read the mouth ulcer tip sheet for more information.
In a few cases, patients developed a rare lung problem called Interstitial Lung Disease (ILD) while receiving afatinib. Notify your healthcare team right away if you develop shortness of breath, new or worsening cough or have any difficulty breathing.
Other Side Effects
Afatinib can affect the function of your liver or cause problems with your heart. Tell your healthcare provider right away if you develop yellowing of the skin or eyes, dark, tea colored urine, pain in the upper abdomen, bleeding/excess bruising, swelling of the feet or ankles, sudden weight gain, shortness of breath or a feeling that your heart is pounding or racing.