Drug-induced interstitial lung disease

Interstitial lung disease (ILD) secondary to drug-induced lung injury is an increasingly common cause of morbidity and mortality. The number of drugs associated with the development of ILD continues to rise, mainly due to the use of novel monoclonal antibodies and biologicals for neoplastic and rheumatological diseases, and includes, among others, chemotherapeutics, molecular targeting agents, immune checkpoint inhibitors, antibiotics, antiarrhythmics and conventional or biological disease-modifying antirheumatic drugs. Drug-induced ILD (DI-ILD) manifests with a variety of clinical patterns, ranging from mild respiratory symptoms to rapidly progressive respiratory failure and death. In most cases, there are no pathognomonic clinical, laboratory, radiological or pathological features and the diagnosis of DI-ILD is suspected in the presence of exposure to a drug known to cause lung toxicity and after exclusion of alternative causes of ILD. Early identification and permanent discontinuation of the culprit drug are the cornerstones of treatment with systemic glucocorticoids being used in patients with disabling or progressive disease. However, for certain drugs, such as checkpoint inhibitors, the frequency of lung toxicity is such that mitigation strategies are put in place to prevent this complication, and occurrence of DI-ILD is not necessarily synonymous with permanent drug discontinuation, particularly in the absence of valid therapeutic alternatives.