A B S T R A C T
Doxycycline is a broad-spectrum tetracycline antibiotic that is frequently used to treat zoonotic illnesses, skin and soft tissue infections, atypical bacterial infections, and respiratory tract infections. A 75-year-old woman was diagnosed with Acute Coronary Syndrome-ST Elevation Anterior Wall Myocardial Infarction (ACS-STEAWMI) due to acute thrombotic blockage of the left anterior descending artery after presenting with significant retrosternal chest discomfort. After a successful first percutaneous coronary intervention with drug-eluting stent insertion, she experienced acute kidney injury, bronchopneumonia with Type I respiratory failure, and significant left ventricular dysfunction. Intravenous piperacillin-tazobactam and oral doxycycline were used as empirical antibacterial therapy for bronchopneumonia. The patient experienced trouble swallowing and decreased oral intake after developing several painful aphthous ulcers involving the oral mucosa around two days after beginning doxycycline. while receiving piperacillin-tazobactam treatment. She also experienced temporary heparinassociated haematuria and hypokalaemia while in the hospital, were treated conservatively without stopping vital cardiovascular medication. Both the Naranjo Adverse Drug Response Probability Scale and the WHO-Uppsala Monitoring Center causation evaluation classified the adverse drug response as probable. This case demonstrates how doxycycline-induced aphthous ulcers in an elderly patient with numerous comorbidities and polypharmacy can be an uncommon but clinically significant adverse medication event. Complete recovery without compromising treatment of the underlying infection was achieved by promptly identifying the temporal link between doxycycline therapy and mouth ulcers, stopping the suspected medication right away, and providing adequate supportive care. This paper highlights the significance of pharmacovigilance, clinical chemist engagement, and interdisciplinary care in detecting rare adverse drug reactions and enhancing patient safety.
Keywords: Doxycycline; Aphthous ulcer; Adverse drug reaction; Pharmacovigilance; Polypharmacy Bronchopneumonia.