Pharmacological Group and Profile
Arbidol belongs to the class of antiviral agents. Unlike medications aimed merely at alleviating symptoms of acute respiratory viral infections (ARVI), it exerts an etiotropic effect by acting directly on the cause of the disease.
In pharmacology exam questions, it is often necessary to differentiate the drug's effects. It should be clearly remembered that Umifenovir does not possess antibacterial activity (it does not destroy bacteria), antihistaminic activity (it does not block histamine receptors), and is not a direct anti-inflammatory agent. Its true pharmacological profile is a virus-specific action combined with immunomodulation.
Mechanism of Action (Pharmacodynamics)
The pharmacodynamics of the drug relies on three main mechanisms that provide comprehensive protection against viral invasion:
- Fusion Inhibition
This is the core mechanism of its direct antiviral action. For a virus to begin replication, it must enter the target cell. The drug specifically interacts with the viral hemagglutinin—a surface glycoprotein responsible for binding to cell receptors. By blocking this protein, Umifenovir prevents a critical step: the fusion of the virion's lipid envelope with the cell membrane. Without fusion, viral entry is blocked, halting the infection process.
- Interferon Induction
In addition to its direct antiviral hit, the drug activates the body's intrinsic defenses. It acts as an interferon inducer, stimulating the production of endogenous proteins that shift neighboring cells into an «antiviral state».
- Immunomodulation
Paradoxically, the drug stimulates the immune system across two key branches:
- Cellular immunity: Stimulation of cells responsible for destroying infected targets.
- Humoral immunity: Stimulation of specific antibody production to neutralize extracellular viral particles.
Spectrum of Activity and Indications
The drug exhibits a marked tropism for respiratory pathogens. Its activity spectrum includes:
- Influenza viruses types A and B;
- Coronaviruses, including the severe acute respiratory syndrome (SARS) pathogen.
In clinical practice, Umifenovir is prescribed for the prevention and treatment of influenza and other acute respiratory viral infections (ARVI).
Formulation and Prescribing Details
The drug is available in solid oral dosage forms—tablets. Three dosage strengths are available: 0.025 g, 0.05 g, and 0.1 g, allowing dosage titration based on the clinical task.
The route of administration is oral (per os). The standard single dose ranges from 0.1 to 0.2 g.
Example prescription for Arbidol (0.1 g tablets): ```latin Rp.: Tab. Arbidolum 0,1 D.t.d. N. 20 S. Take 1-2 tablets orally per dose. ```