A systematic review of clinical patterns and outcomes of acute organophosphate poisoning in Nigeria

Abstract

Organophosphate (OP) poisoning is a major public health concern in Nigeria, driven by the widespread availability of pesticides such as Sniper (dichlorvos) and Otapiapia. Despite its high morbidity and mortality, local evidence remains fragmented across isolated case reports and single-centre reviews. This systematic review aggregated the clinical patterns, exposure characteristics, management approaches, and outcomes of OP poisoning in Nigeria. A comprehensive search was conducted (January 2000–August 2025) across PubMed, AJOL, Scopus, and Google Scholar, using PRISMA guidelines. Eligible studies were case reports, case series, retrospective or prospective clinical reviews, cross-sectional and cohort studies that reported OP-specific data in Nigerian patients. Data on demographics, exposure, clinical features, management, and outcomes were extracted using a standardised form and pooled together descriptively. Twenty-three studies (176 OP cases) were reported. Males constituted 54.5% of cases (M: F ratio 1.2:1). Children accounted for 55.0% of cases, with accidental ingestion predominating (60.3%). The pooled case fatality rate was 23.9% (42/176). Intensive Care Unit (ICU) admission was documented in at least 7 cases across studies that reported it. Atropine was the most commonly used antidote (reported in 12/23 studies); pralidoxime was reported in only 2 studies, reflecting widespread unavailability. OP poisoning in Nigeria is common, particularly among children (accidental) and young adults (intentional). Resource limitations, delayed presentation, and antidote shortages are major barriers. Strengthening regulation, education on safe storage, poison control centres, and mental health support are urgently needed.