The most common adverse effects associated with erlotinib hydrochloride are rash and diarrhoea. Moderate or severe diarrhoea should be treated with an appropriate antidiarrhoeal such as loperamide; dose reduction may be needed. In more severe or persistent cases leading to dehydration, therapy should be stopped temporarily. Other common adverse effects include other gastrointestinal disturbances, gastrointestinal bleeding, fatigue, alopecia, stomatitis, pruritus, dry skin, paronychia, conjunctivitis, keratoconjunctivitis sicca, epistaxis, and abdominal pain. Alterations in liver function tests have occurred. Rare cases of hepatic failure, including fatalities, have been reported. Interstitial lung disease has also been reported; fatalities have occurred. Erlotinib treatment should be interrupted if unexplained pulmonary symptoms occur, such as dyspnoea, cough, and fever.