J Clin Pharm Ther. 2020;00:1–6. wileyonlinelibrary.com/journal/jcpt | 1 © 2020 John Wiley & Sons Ltd Received: 23 September 2020 | Revised: 6 October 2020 | Accepted: 7 October 2020 DOI: 10.1111/jcpt.13305 ORIGINAL ARTICLE Observational study of the effects of Favipiravir vs Lopinavir/Ritonavir on clinical outcomes in critically Ill patients with COVID-19 Havva Kocayiğit MD 1 | Kezban Özmen Süner MD 2 | Yakup Tomak MD 1 | Gürkan Demir MD 1 | Selçuk Yaylacı MD 3 | Hamad Dheir MD 4 | Ertuğrul Güçlü MD 5 | Ali Fuat Erdem MD 1 Presentation at a meeting: None. 1 Department of Anaesthesiology and Reanimation, Sakarya University Education and Research Hospital, Sakarya, Turkey 2 Department of Intensive Care, Sakarya University Education and Research Hospital, Sakarya, Turkey 3 Department of Internal Medicine, Sakarya University Education and Research Hospital, Sakarya, Turkey 4 Department of Nephrology, Sakarya University Education and Research Hospital, Sakarya, Turkey 5 Department of Infectious Diseases and Clinical Microbiology, Sakarya University Education and Research Hospital, Sakarya, Turkey Correspondence Havva Kocayigit, Department of Anaesthesiology and Reanimation, Sakarya University Education and Research Hospital, Adnan Menderes Caddesi Saglik Sokak. 54100, Sakarya, Turkey. Email: havvakocayigit@gmail.com Abstract What is known and objectives: In November 2019, several patients were diagnosed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Wuhan, China. So far, there are no specific treatments with proven high efficacy in patients with SARS-CoV-2. Presently, several drugs, such as hydroxychloroquine, ribavirin, favipiravir (FVP), lopinavir/ritonavir (LPV/r), remdesivir and oseltamivir, have been suggested as effective treatments for SARS-CoV-2. The aim of this study was to de- scribe the clinical experience with FPV and LPV/r in critically ill patients with COVID- 19 at Sakarya University Education and Research Hospital. Methods: The study included 107 consecutive patients who had a laboratory confir- mation of COVID-19 and were admitted to the intensive care unit (ICU) between 19 March and 19 May 2020. Follow-up continued through 30 May 2020 when the last observed patients were discharged. Results and discussion: Of the 107 patients, 65 received FPV (Group FPV) and 42 received LPV/r (Group LPV/r). The two groups were similar in terms of demographic data and clinical findings. 43 (66.2%) of the 65 patients in the FPV group and 23 (54.8%) of the 42 patients in the LPV/r group died ( p = 0.237). The median ICU stay was 6.6 (IQR, 3–10) days in the FPV group and 9 (IQR, 6–16) days in the LPV/r group, which was a statistically significant difference ( p = 0.010). What is new and conclusion: The length of hospital stay was significantly lower in the FVP group compared to the LPV/r group among patients who were discharged from the ICU. Although the analysis was done with a limited number of patients and the observed difference in mortality rate is of some concern, FVP treatment may be more beneficial than LPV/r in terms of effective use in the ICU. KEYWORDS COVİD-19, favipiravir, lopinavir