Inclusion Criteria:  Men and women aged 18 and over Can give informed consent Confirmed positive result for SARS-CoV-2 within 72 hours from the date the result was issued (according to the laboratory report) Patient presently symptomatic with one or more of the following symptoms: fever, cough, myalgia, mild dyspnoea, chest pain, diarrhea, nausea, vomiting, anosmia, lack of taste, sore throat, nasal congestion At initial screening, the subject will report at least one and no more than 3 of the following risk factors for clinical worsening: age ≥40, obesity, hypertension, diabetes, pulmonary disease (e.g., asthma, COPD), and immune disorders (e.g. rheumatoid arthritis, lupus), neurological diseases: e.g. after a distant stroke or trauma to the brain, multiple sclerosis, dementia and other neurodegenerative diseases) Patients hospitalized due to meeting the above criteria and requiring observation in a hospital or outpatient setting.  Exclusion Criteria:  Disease severe enough to meet the study's primary endpoint of clinical worsening (eg, current O2 saturation <92% with patient exposure to room air, current use of supplemental oxygen to maintain O2 saturation ≥ 92%). WHO score ≥4 (requires oxygen therapy during hospitalization) Concomitant diseases which, in the opinion of the attending physician, prevent the patient from participating in the study, such as: decompensated cirrhosis, active ulcer disease, epilepsy and symptomatic convulsions, untreated angle-closure glaucoma determined on the basis of the patient's interview and / or medical documentation . In addition, immunocompromised patients (solid organ transplant, BMT, AIDS, renal failure (patients with renal impairment may develop drug poisoning) or other diseases not mentioned and other diseases treated with biological, immunological and / or steroids in high doses will not be eligible for the study. doses (> 20 mg prednisone daily). Hypersensitivity to any component of the preparation, severe congestive heart failure, cardiomyopathy, myocarditis, II-III degree AV block, bradycardia, clinically significant prolongation of the QT interval, or a family history of congenital long QT syndrome, severe ventricular arrhythmias (including torsade de pointes), concomitant use of drugs that prolong the QT interval, hypokalaemia, hypomagnesaemia, Pregnancy, the period of breastfeeding. Parallel intake of memantine or other drugs acting on the CNS (neuroleptics, anxiolytics, antiepileptic drugs, antidepressants). Other neurological conditions with agitation or confusion, delirium syndromes or psychoses. Receipt of a partial or full vaccination schedule against SARS-CoV-2 is also an exclusion criterion from the study.