We report a rare case of concurrent onset of osimertinib-induced heart failure and metronidazole-induced encephalopathy during treatment of a brain abscess. A 78-year-old female with lung adenocarcinoma presented with neurological symptoms and was diagnosed with a brain abscess. During treatment, she developed heart failure and encephalopathy, linked to osimertinib and metronidazole, respectively. Following the discontinuation of these drugs, her symptoms gradually improved. This case underscores the need for careful monitoring of adverse drug reactions, especially in patients with significant weight loss. Regular cardiac and neurological assessments are recommended to promptly identify and manage such events.

Concurrent Onset of Osimertinib-Induced Heart Failure and Metronidazole-Induced Encephalopathy During Brain Abscess Treatment: A Report of a Rare Case