ABSTRACT
This chapter provides a general overview of allergic drug reactions, focusing where necessary on those affecting the lung. A drug allergy is an immunologically mediated reaction that exhibits specificity and recurrence on re-exposure to the offending drug. Lung effects have been witnessed in up to 6 per cent of patients taking at least 400 mg amiodarone per day; and although lower doses are stated to be safer, acute lung involvement is seen also at 200 mg/day. Acute pulmonary reactions caused by fibrogenic agents such as methotrexate also appear to be mediated by hypersensitivity mechanisms. Host-related factors can predispose to drug allergy probably by acting on the way the drug is handled in the body or by unknown pharmacodynamic mechanisms. T-cell-mediated reactions are probably the most prevalent type of reaction to drugs, and have been implicated in many different types of allergic reactions, including those involving the lungs.
