Were medicine quality and pharmaceutical management contributing factors in diminishing artemisinin efficacy in Guyana and Suriname?

BACKGROUND: Recent studies in Guyana and Suriname unveiled diminished efficacy of artemisinin derivatives based on day-3 parasitaemia. The migrant characteristics of the population at risk and the potential development of resistance pose a serious health threat in the region. Assessment of factors that may have contributed to this situation is warranted, and analysis of the data generated in those countries on quality and pharmaceutical managements of anti-malarials may contribute to a better understanding of this occurrence. METHODS: Data on malaria medicine quality and pharmaceutical management, generated in the context of the Amazon Malaria Initiative (AMI), was reviewed and discussed. RESULTS: Numerous substandard artemisinin-containing malaria medicines were identified in both countries, particularly in Guyana, where a larger number and variety of anti-malarials were sampled. Poor quality was more frequent in the private and informal sector than in the public sector, posing a greater threat to the populations at risk, which are mostly located in hard to reach areas with scarce public facilities. Stock-outs identified in the public sector in Guyana could enhance the need to access those alternative sectors, exacerbating the risk of utilizing poor quality medicines. The availability of monotherapies and other non-recommended therapies for Plasmodium falciparum malaria, could also have contributed to the diminished efficacy. The type of quality deficiencies identified -reduced content of active pharmaceutical ingredient (API) and/or poor dissolution- and the irrational use of non-recommended treatments could result in non-sustained or lower levels of API in blood, favouring survival of more resistant mutants by exposing parasites to sub-lethal doses of the active ingredient. CONCLUSIONS: The quality of malaria medicines and the availability and use of non-recommended treatments could have played a role in the diminished efficacy of artemisinin derivatives described in Guyana and Suriname. However, also other factors need to be considered and a more comprehensive and extensive assessment on quality and pharmaceutical management is necessary to establish a tighter cause-effect correlation. Nevertheless, relevant authorities in these and neighbouring countries should take into consideration the reviewed data to properly address the problem when implementing corrective actions.