There is no fixed period of time for how long the side effects of taking Afatinib will disappear, and the time for the side effects to disappear is related to the type of side effects, the degree of side effects and the treatment. Afatinib is indicated for patients with locally advanced or metastatic non-small cell lung cancer with sensitive mutations in the EGFR gene who have not been previously treated with EGFR-TKI analogues, or locally advanced or metastatic squamous lung cancer whose disease has progressed during or after platinum-based chemotherapy. Some of the more common side effects of afatinib are diarrhea, vomiting, rash, and malaise. Different patients may experience different side effects, the extent of which varies from person to person, and the management of the side effects may also vary. For example, some people experience severe diarrhea and others experience mild malaise. Severe diarrhea may last for weeks if left untreated, and mild malaise may disappear on its own after a few days without treatment. Medications should be applied under the direction of a doctor, not on your own.