The recommended starting dose of Giotrif is 40 mg by mouth once daily.  Take on an empty stomach at least 1 hour before or 3 hours after eating.

Afatinib belongs to the class of anti-cancer medications called protein kinase inhibitors. It  attaches to epidermal growth factor receptor (EGFR) molecules that have certain kinds of mutations. It then helps block cancer-causing signals that come from these molecules.

The most common side effects:

• diarrhea
• rash
• mouth sores
• nail inflammation
• dry skin
• acne
• decreased appetite,
• nausea, vomiting
• itching

Other possible side effects:

• Inflammation of the urinary bladder resulting in a burning sensation during urination and frequent urgent need to urinate
• Dehydration
• Low blood potassium levels
• Taste disturbance or loss of taste
• Inflammation or infection of the membrane lining the eyelids
• Dry eye
• Runny nose
• Indigestion, stomach pain
• Inflammation of the lips
• Redness, swelling, and pain on the palms of the hands and/or the soles of the feet
• Muscle spasm
• Kidneys not working properly or failing
• Fever or high temperature
• Weight loss
• Increase in liver enzymes
• Inflammation of the cornea
• Inflammation or scarring of the lungs
• Nail disorders

Use afatinib with caution if you:

• have liver disease or kidney disease;
• have a dairy or lactose intolerance;
• have a history of lung inflammation (interstitial lung disease)
• have a history of severe dry eye or eye inflammation (keratitis) or use contact lenses;
• have heart problems;
• are female and have a body weight of less than 50 kg

Drug interactions - The following may interact with afatinib.  Discuss use with your physician or pharmacist:

• Antifungals (such as ketoconazole, itraconazole)
• Macrolide antibiotics such as clarithromycin and erythromycin
• Drugs to treat tuberculosis (TB) (such as rifampicin)
• Drugs to treat HIV-AIDS and viral infections (such as nelfinavir, saquinavir)
• Calcium channel blockers (such as verapamil)
• Antiarrhythmics (such as quinidine, amiodarone)
• Anticonvulsants (such as carbamazepine, phenytoin and phenobarbital)
• Cancer drugs
• Immunosuppressants (such as tacrolimus)
• Atorvastatin
• St. John’s Wort

Use in pregnancy: There are no studies on the use of afatinib in human pregnancy. The animal data suggest risk, so at this time, use during pregnancy is not advised.  Female patients using afatinib are advised to use highly effective birth control methods during use and for 2 weeks after discontinuation.

Use in breastfeeding: It is not known if afatinib passes into breast milk.  Due to the potential for serious harm to a baby if exposed to this medication, use is not recommended.