Rituximab Infusion-Related Reactions in Routine Clinical Practice: A Retrospective Pharmacovigilance Study from Iraq

Abstract

Background: Rituximab (RTX) is widely used for autoimmune and haematological diseases, but infusion-related adverse drug reactions (ADRs) remain a clinically important safety concern in routine care. Aim: This retrospective pharmacovigilance study described rituximab-associated adverse drug reactions reported at Marjan Teaching Hospital, Iraq, over a six-month period. Methods: Data were collected from routine pharmacovigilance reports and medical records for patients with suspected rituximab-associated adverse drug reactions from January to 10th June 2026. Extracted variables included demographic characteristics, underlying diagnosis, clinical manifestations, seriousness, management, outcomes, and causality assessment. Causality was assessed using the World Health Organization–Uppsala Monitoring Centre (WHO-UMC) system, and descriptive statistics were performed using GraphPad Prism version 10.0. Results: Among 312 rituximab infusions, 56 patients experienced documented adverse drug reactions, yielding an incidence of 17.9% (95% CI: 13.8–22.5%). Most patients were female (96.4%), and the mean age was 42.8 years. Rheumatoid arthritis was the most common underlying diagnosis (64.3%), followed by systemic lupus erythematosus (25.0%). Shortness of breath, itching, and cough were the most frequently reported manifestations, while 50.0% of reactions were classified as serious. Most reactions were considered probable/likely by WHO-UMC assessment. All patients recovered, and rituximab was resumed at a slower infusion rate in 85.7% of cases. Conclusion: The findings support careful infusion monitoring, prompt recognition of symptoms, and structured pharmacovigilance reporting to improve patient safety during rituximab therapy.