Mouth sores, pain/redness/swelling of lips, dry/itchy skin, acne, nose bleed, runny nose, and loss of appetite may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Diarrhea is a common side effect. Drink plenty of fluids as directed by your doctor to reduce your risk of losing too much body water (dehydration). Your doctor may prescribe anti-diarrhea medication (such as loperamide) to control your symptoms. Tell your doctor right away if you develop: severe or persistent diarrhea, symptoms of dehydration (such as unusual decreased urination, unusual dry mouth/thirst, fast heartbeat, or dizziness/lightheadedness).
Tell your doctor right away if you have any serious side effects, including: signs of eye disease (such as vision changes, eye redness/pain, light sensitivity, eye discharge), signs of low level of potassium in the blood (such as muscle cramps, weakness, irregular heartbeat), signs of bladder infection (such as burning/pain when you urinate, urgent or frequent urination, fever), signs of skin infection around nails/toenails (such as skin irritation/redness around the nail, change in nail color).
Get medical help right away if you have any very serious side effects, including: symptoms of lung problems (such as trouble breathing, chest pain), symptoms of heart failure (such as swelling ankles/feet, unusual tiredness).
Afatinib may infrequently cause serious (possibly fatal) liver disease. Get medical help right away if you have any symptoms of liver damage, including: dark urine, persistent nausea/vomiting/loss of appetite, stomach/abdominal pain, yellowing eyes/skin.
Afatinib can commonly cause a rash that is usually not serious. However, you may not be able to tell it apart from a rare rash that could be a sign of a severe reaction. Therefore, tell your doctor immediately if you develop any rash.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.