Antiviral agent.
Specifically inhibits in vitro influenza viruses A and B (Influenzavirus A, B), including the highly pathogenic subtypes A(H1N1) pdm09 and A(H5N1), as well as other viruses that cause acute respiratory infections (ARIs) (severe acute respiratory syndrome (SARS)-associated coronavirus (Coronavirus), rhinovirus (Rhinovirus), adenovirus (Adenovirus), respiratory syncytial virus (Pneumovirus), and parainfluenza virus (Paramyxovirus).
Based on its mechanism of antiviral action, it is a fusion inhibitor; it interacts with viral hemagglutinin and prevents the fusion of the viral lipid membrane and cell membranes.
It has a moderate immunomodulatory effect and increases the body's resistance to viral infections. It has interferon-inducing activity. In a mouse study, interferon induction was observed after just 16 hours, and high interferon titers persisted in the blood for up to 48 hours after administration. It stimulates cellular and humoral immune responses: it increases the number of lymphocytes in the blood, particularly T cells (CD3), increases the number of T helper cells (CD4) without affecting the level of T suppressor cells (CD8), normalizes the immunoregulatory index, stimulates the phagocytic function of macrophages, and increases the number of natural killer cells (NK cells).
Therapeutic efficacy in viral infections is manifested by a reduction in the duration and severity of the disease and its main symptoms, as well as a decrease in the incidence of complications associated with viral infections and exacerbations of chronic bacterial diseases. A clinical trial demonstrated that umifenovir's effect in treating influenza and acute respiratory viral infections in adults is most pronounced during the acute phase of the disease, resulting in a shorter symptom resolution time, reduced severity of symptoms, and shorter viral clearance time.
Umifenovir therapy results in a higher rate of symptom resolution on the third day of therapy compared to placebo. Sixty hours after the start of therapy, the resolution of all laboratory-confirmed influenza symptoms is more than five times higher than in the placebo group. Umifenovir has been shown to significantly impact the rate of influenza virus clearance, demonstrated, in particular, by a decrease in viral RNA detection on the fourth day.
Umifenovir is classified as a low-toxicity drug (LD50>4 g/kg). It has no adverse effects on the human body when administered orally at recommended doses.
