Pharmacological group and action profile
Arbidol belongs to the class of antivirals. Unlike medications aimed at relieving ARVI symptoms, it has an etiotropic effect—acting directly on the cause of the disease.
Pharmacology test questions often require differentiating drug effects. You should clearly remember that Umifenovir does not possess antibacterial action (does not destroy bacteria), antihistamine action (does not block histamine receptors), and is not a direct anti-inflammatory agent. Its true pharmacological profile is a virus-specific action in an inseparable combination with immunomodulation.
Mechanism of action (Pharmacodynamics)
The drug's pharmacodynamics is based on three main mechanisms that provide comprehensive body protection against viral invasion:
- Fusion inhibition
This is the key mechanism of direct antiviral action. For a virus to begin replication, it must penetrate inside the target cell. The drug specifically interacts with the viral hemagglutinin—a surface protein responsible for binding to receptors. By blocking this protein, Umifenovir prevents a critically important stage: the fusion of the virion's lipid envelope with the cell membrane. No fusion means no virus entry into the cell, interrupting the infectious process.
- Interferon induction
In addition to a direct strike on the virus, the drug activates the body's own defense systems. It acts as an interferon inducer, stimulating the production of endogenous proteins that put neighboring cells into an "antiviral state".
- Immunomodulation
The drug has a stimulating effect on the immune system, affecting both of its key links:
- Cellular immunity: stimulation of cells responsible for destroying already infected targets.
- Humoral immunity: stimulation of specific antibody production to neutralize viral particles outside cells.
Spectrum of activity and indications
The drug exhibits a pronounced tropism for respiratory infection pathogens. Its spectrum of activity includes:
- Influenza A and B viruses;
- Coronaviruses, including the causative agent of SARS (Severe Acute Respiratory Syndrome).
In clinical practice, Umifenovir is prescribed for the prevention and treatment of influenza and other acute respiratory viral infections (ARVI).
Dosage form and prescribing features
The drug is available in a solid dosage form: tablets. Three dosage options are available in pharmacies: tablets of 0.025 g, 0.05 g, and 0.1 g, which allows dose titration depending on the clinical task.
The route of administration is oral (per os). The standard single dose ranges from 0.1 to 0.2 g.
Prescription example for Arbidol (0.1 g tablets): ```latin Rp.: Tab. Arbidoli 0.1 D.t.d. N. 20 S. Orally, 1-2 tablets per dose. ```
Briefly: answers to topical questions
Against which viruses is Arbidol active?
Arbidol (umifenovir) has a broad spectrum of activity against respiratory infection pathogens. The drug specifically inhibits the following viruses:
- Influenza A and B viruses (Influenza virus A, B / Influenzavirus A, B) — including highly pathogenic subtypes A(H1N1)pdm09 and A(H5N1).
- Coronaviruses (Coronavirus) — including SARS causative agents and SARS-CoV-2.
- Rhinoviruses (Rhinovirus) — including rhinovirus type 14.
- Adenoviruses (Adenovirus).
- Respiratory syncytial virus (Pneumovirus) — RSV.
- Parainfluenza viruses (Paramyxovirus) — including parainfluenza virus type 3.
What are the contraindications for prescribing umifenovir?
Contraindications to prescribing umifenovir include:
- Hypersensitivity to any component of the drug.
- First trimester of pregnancy.
- Breastfeeding period.
In the second and third trimesters of pregnancy, the drug is used with caution.
"ARBIDOL prevents the virus from BOARDING the cell" — binds hemagglutinin and blocks the fusion of the viral envelope with the cell membrane.
Class and exam questions
What pharmacological group does Arbidol belong to?
The drug belongs to antivirals. It has a direct virus-specific action and is not an antibiotic or an antihistamine.
What is the virus-specific action of umifenovir?
It acts as a fusion inhibitor. By binding to viral hemagglutinin, the drug blocks the fusion of the virus lipid envelope with the target cell membrane.
Which viruses does the drug act against?
The spectrum of activity includes influenza A and B viruses, as well as coronaviruses (including the causative agent of Severe Acute Respiratory Syndrome — SARS).
How does the drug affect the immune system?
It induces interferon and stimulates both cellular and humoral immune responses, increasing the body's overall resistance.
What else to study on this topic
- Structure of the influenza virus: the role of surface proteins (hemagglutinin and neuraminidase).
- Mechanism of enveloped virus entry into the cell (fusion process).
- Interferon system: classification and mechanism of host antiviral defense.
- Cellular and humoral immunity in acute viral infections.
- Comparative characteristics of antiviral drugs (fusion inhibitors, neuraminidase inhibitors, M2 channel blockers).
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