Persistent Chloroquine use in Nigeria: Evidence, Drivers, Drug Resistance and Implications for Antimalarial Stewardship

Abstract

Chloroquine was once the mainstay of uncomplicated malaria treatment in Nigeria because of its low cost, wide availability, simple dosing regimen, and long history of use. However, widespread use and increasing Plasmodium falciparum resistance led to declining therapeutic effectiveness and the subsequent adoption of artemisinin-based combination therapies (ACTs) as the recommended treatment for uncomplicated malaria. Despite its withdrawal from national treatment policy, chloroquine remains available and is reportedly used in some Nigerian communities and medicine outlets. This review examines the persistence of chloroquine use in Nigeria, with particular attention to Northern Nigeria, and considers its implications for antimalarial stewardship, drug-resistance containment, and sustainable malaria control. A narrative review of published evidence and relevant malaria-treatment policies was undertaken. Evidence on continued chloroquine use, medicine availability, self-medication, treatment-seeking behaviour, provider and vendor practices, and molecular markers of chloroquine resistance was examined. Available evidence indicates that chloroquine remains accessible and is still used in some settings despite its withdrawal from recommended malaria-treatment protocols. Its continued use appears to be associated with historical familiarity, low cost, easy access, self-medication, presumptive treatment of fever, limited diagnostic services, variable availability or affordability of ACTs, and practices among medicine vendors and health-care providers. Molecular surveillance indicates that chloroquine-resistance markers have declined in some settings following withdrawal of chloroquine, but resistant parasite genotypes remain detectable. However, declining resistance-marker frequencies alone do not provide sufficient evidence to support routine reintroduction of chloroquine. Persistent chloroquine use remains a policy-practice concern with implications for appropriate malaria case management and sustainable malaria control. Strengthening antimalarial stewardship requires reliable access to quality-assured ACTs and rapid diagnostic tests, improved regulation of medicine outlets, provider and vendor training, community education, routine surveillance of antimalarial medicine use, and continued molecular and therapeutic-efficacy surveillance.