Inclusion Criteria:  Male and female patients ≥ 18 years receiving DEX for COVID-19 Stable dose of DEX for at least 24 hours BMI between 18.5 and 25 or ≥ 30 kg/m2 Understanding of French orEnglish languages and ability to give a written inform consent  Exclusion Criteria:  Medical history of cirrhosis (Child Pugh B and C) or/and nonalcoholic fatty liver disease. History of bariatric or other gastric surgery that may affect the drug absorption Patient already included in a clinical trial of an investigational drug Use of drugs that may affect CYP3A activity * *based on the 'drug interactions and cytochromes P450' table published by The Division of clinical Pharmacology and Toxicology [15], HUG and on the investigator's knowledge and on the drug interactions website from the University of Liverpool (https://www.covid19- druginteractions.org/checker).