Eligibility Criteria:
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.