nutrients Review Emergent Drug and Nutrition Interactions in COVID-19: A Comprehensive Narrative Review Duygu A ˘ gagündüz 1, * , Men¸ sure Nur Çelik 1 , Merve Esra Çıtar Dazıro ˘ glu 1 and Raffaele Capasso 2, *   Citation: A˘ gagündüz, D.; Çelik, M.N.; Çıtar Dazıro ˘ glu, M.E.; Capasso, R. Emergent Drug and Nutrition Interactions in COVID-19: A Comprehensive Narrative Review. Nutrients 2021, 13, 1550. https:// doi.org/10.3390/nu13051550 Academic Editors: Carlo Agostoni and Gregorio Paolo Milani Received: 19 March 2021 Accepted: 28 April 2021 Published: 4 May 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Department of Nutrition and Dietetics, Faculty of Health Sciences, Gazi University, Emek, Ankara 06490, Turkey; dyt.mensurenurcelik@gmail.com (M.N.Ç.); esracitar@gmail.com (M.E.Ç.D.) 2 Department of Agricultural Sciences, University of Naples Federico II, 80055 Naples, Italy * Correspondence: duyguturkozu@gazi.edu.tr (D.A.); rafcapas@unina.it (R.C.) Abstract: Coronaviruses are a large family of viruses that are known to cause respiratory tract infections ranging from colds to more severe diseases, such as Middle East Respiratory Syndrome (MERS) and the Severe Acute Respiratory Syndrome (SARS). New Coronavirus Disease 2019 (COVID- 19), which led to deaths as well as social and economic disruptions, is an ongoing worldwide pandemic caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Currently, there is no approved treatment for COVID-19. Hence, only supportive care has been approved by the World Health Organization (WHO) for now. Pharmacological agents used for the adjunctive treatment of COVID-19 following the current literature and clinical experiences include antiviral, anti- inflammatory, and anti-malaria drugs, and other traditional or untraditional treatments. However, it has been reported that the use of these drugs may have some negative effects and comorbidities. Moreover, the current data have indicated that the risk of drug-drug interactions may also be high in polypharmacy cases, especially in elderly people, some comorbidity situations, and intensive care unit (ICU) patients. It is highly possible that these situations can not only increase the risk of drug-drug interactions but also increase the risk of food/nutrition-drug interactions and affect the nutritional status. However, this issue has not yet been entirely discussed in the literature. In this review, current information on the possible mechanisms as well as pharmacokinetic and pharmacodynamic effects of some pharmacological agents used in the treatment of COVID-19 and/or their secondary interactions with nutrition were evaluated and some future directions were given. Keywords: COVID-19; drug; nutrition interaction 1. Introduction Coronaviruses are a large family of viruses that can cause disease in animals or humans. In humans, several coronaviruses are known to cause respiratory tract infections ranging from colds to more severe diseases such as Middle East Respiratory Syndrome (MERS) and the Severe Acute Respiratory Syndrome (SARS). New Coronavirus Disease 2019 (COVID-19) is an ongoing worldwide emergency caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) [1]. The SARS-CoV-2 virus was first reported in a group of patients who developed respiratory symptoms (fever, cough, shortness of breath) in Wuhan Province, China, in late December 2019. As a result of research, it was identified on 13 January 2020. COVID-19, which was declared a pandemic by the World Health Organization (WHO) on 11 March 2020, has and continues to have significant effects in all areas worldwide [2,3]. In the beginning of 2021, several new variants of SARS-CoV-2, such as the South Africa (501Y.V2 or B.1.351), United Kingdom (N501Y or B.1.1.7), and Brazil (P.1) variants, were also detected and have been spreading rapidly worldwide [4]. COVID-19 has often been reported to have a four-stage course. In the first stage, the symptoms are characterized by infection of the upper respiratory tract, while dyspnea and pneumonia begin in the second stage. A cytokine storm is seen in the third stage with a Nutrients 2021, 13, 1550. https://doi.org/10.3390/nu13051550 https://www.mdpi.com/journal/nutrients