Loeffler's syndrome: an uncommon adverse reaction to imipramine

Loeffler's syndrome (simple pulmonary eosinophilia) is an uncommon side effect of tricyclic antidepressants. It is an allergic reaction characterised by diffuse eosinophilic lung infiltrates and a peripheral blood eosinophilia. It is often asymptomatic, but can also present with mild to moderate pulmonary symptoms. Although it has been only rarely reported with imipramine and desmethylimipramine, it may be a more common side effect to tricyclic antidepressants than has been previously recognized.