Silva‑Pinto et al. Malar J (2017) 16:43 DOI 10.1186/s12936‑017‑1698‑y RESEARCH Artemether‑lumefantrine and liver enzyme abnormalities in non‑severe Plasmodium falciparum malaria in returned travellers: a retrospective comparative study with quinine‑doxycycline in a Portuguese centre André Silva-Pinto * , Rogério Ruas, Francisco Almeida, Raquel Duro, André Silva, Cândida Abreu and António Sarmento Abstract Background: Artemisinin-based therapy is the current standard treatment for non-severe malaria due to Plasmo- dium falciparum. The potential for asymptomatic liver toxicity of this therapy and its implication in clinical practice is currently unknown. The aim of this study is to assess the hepatic function in patients treated with a standard three- day artemisinin-based regimen and to compare it with the quinine-doxycycline regimen. Methods: Retrospective and comparative study of returned adult travellers admitted with non-severe P. falciparum malaria. Fifty-seven patients were included: 19 treated with artemisinin-based therapy and 38 with quinine-doxycy- cline therapy. Results: During treatment, when compared with quinine-doxycycline group, the artemisinin-lumefantrine group presented a higher proportion of significant liver enzyme abnormalities (42 vs. 5%, p < 0.01) and a higher peak value of aspartate aminotransferase (131 vs. 64 U/L, p < 0.01) and alanine aminotransferase (99 vs. 75 U/L, p = 0.05). None of the patients was symptomatic, there were no treatment interruptions and all patients achieved clinical cure. Conclusions: Treatment of uncomplicated falciparum malaria with artemisinin-based therapy might cause asympto- matic liver enzyme abnormalities in the first days of treatment. Nevertheless, these liver enzyme abnormalities seem to be harmless, asymptomatic and self-limited. Keywords: Malaria, Artemether–lumefantrine, Liver dysfunction, Plasmodium falciparum © The Author(s) 2017. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Background Artemisinin based combination therapy (ACT) is the current standard treatment for uncomplicated malaria caused by Plasmodium falciparum [1]. Owing to their rapid onset of action and quick elimination, artemisinin derivatives are very efective in reducing parasite load and have favourable safety and tolerability profles [2, 3]. In Portugal, artemether/lumefantrine fxed dose combi- nation (AL), currently the only available ACT, came into medical use in 2013 and is an alternative to quinine plus doxycycline (QD), the previous frst-line regimen [1]. Te main reasons for this paradigm change are the safety and tolerability profles of AL and the remaining ACT regi- mens compared to QD [3, 4]. Open Access Malaria Journal *Correspondence: pintoandre@gmail.com Infectious Diseases Department, Centro Hospitalar São João, Alameda Professor Hernani Monteiro, 4200 Porto, Portugal