Olfactory Hallucinations and Acute Psychosis Induced by Trimethoprim-Sulfamethoxazole: A Case Report and Literature Review

Trimethoprim-sulfamethoxazole (TMP-SMX) is a widely prescribed antibiotic, with neuropsychiatric toxicity being a rare but severe complication. We present a 72-year-old immunocompetent woman who developed acute psychosis, characterized by homicidal ideation and rare olfactory hallucinations, 3 days after treatment with oral TMP-SMX for a urinary tract infection. Symptoms resolved completely within 24 hours of drug discontinuation. A literature review identified 9 similar cases confirming rapid onset and resolution. This case highlights the potential for severe, idiosyncratic central nervous system toxicity from TMP-SMX in immunocompetent adults, emphasizing the need for prompt recognition and drug cessation to ensure patient safety.