Subcutaneous Apomorphine-Induced Pneumonitis: An Uncommon Pulmonary Adverse Event

Introduction Apomorphine is a potent dopaminergic agonist widely used in the management of motor fluctuations in advanced Parkinson’s disease. Although generally well tolerated, rare pulmonary adverse drug reactions (ADRs) may occur. We report a case of probable apomorphine-induced pneumonitis associated with subcutaneous administration. Case Presentation A 62-year-old Caucasian male with multiple comorbidities presented to the emergency department with headache, non-productive cough, central chest pain, fever, and dyspnea over the past 48 hours ( 3 weeks after initiation of subcutaneous apomorphin). Chest X-ray revealed bilateral hilar infiltrates and basal consolidation. CT scan showed organizing pneumonia (OP)-like pattern. Extensive microbiological evaluation of bronchoalveolar lavage and bronchial aspirate samples, including bacterial, fungal, mycobacterial, viral, and atypical pathogen testing, was negative. Lack of response to broad-spectrum antibiotics raised the suspicion of drug-induced pneumonitis due to subcutaneous apomorphine. Antibiotics were discontinued, and corticosteroid therapy (methylprednisolone 40 mg/day) was initiated with gradual tapering resulted in rapid clinical improvement and complete radiological resolution within one month. Conclusion The temporal relationship between apomorphine initiation and symptom onset, compatible clinical and radiological findings, extensive microbiological exclusion of infectious causes, and favourable response after drug withdrawal and corticosteroid therapy supported the diagnosis of probable apomorphine-induced pneumonitis.