Paul N. NewtonFacundo M. FernándezMichael D. GreenJoyce Primo-CarpenterNicholas J. WhiteWellcome Trust-Mahosot HospitalUniversity of OxfordGeorgia Institute of TechnologyCenters for Disease Control and PreventionU.S. PharmacopeiaMahidol University2018-09-242018-09-242010-01-01Antimicrobial Resistance in Developing Countries. (2010), 413-4432-s2.0-84856098870https://repository.li.mahidol.ac.th/handle/20.500.14594/29287© 2010 Springer Science Business Media, LLC. All rights reserved. There is considerable interest in optimizing the therapy for important infections in developing countries and in making the best treatments readily available and inexpensive. There is also great concern that resistance to anti-infective drugs is worsening, putting affordable treatments at risk. We argue that an important, but usually neglected aspect of these problems is drug quality. Drugs may be of poor quality if they are counterfeit, substandard or degraded. Few objective data on the prevalence of poor-quality drugs exist but surveys suggest that an alarming proportion of antimalarials and antibiotics in much of the developing world are of poor quality. For individual patients these will increase mortality and morbidity and lead to loss of faith in medicines and health systems. Counterfeit, substandard or degraded drugs with sub-therapeutic concentrations of the active ingredient or the wrong active ingredient are likely to engender the emergence and spread of resistance to these anti-infectives. Although modelling suggests that poor-quality drug should worsen drug resistance, there is sparse evidence from the field, as there has been little research. It will be very difficult to distinguish the effects of poor-drug quality and reduced patient adherence and incorrect health worker prescribing on the spread of resistance. Strengthening drug regulatory authorities, improving quality of drug production and facilitating the availability of relatively inexpensive, good-quality anti-infectives are likely to be key factors in improving drug quality.Mahidol UniversityImmunology and MicrobiologyChapterSCOPUS10.1007/978-0-387-89370-9-24