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Interferon Drugs

*Interferona*

For medical students2 min readUpdated 2026-10-10

Interferons are a family of small regulatory glycoproteins that protect the body against viral infections and control cell growth. In pharmacology, they are used as potent antiviral, antineoplastic, and immunomodulating agents.

Main TargetViral infections (hepatitis, HIV, HPV, herpes, influenza)

Route of AdministrationParenteral or topical only (completely degraded in the gastrointestinal tract)

Common Side EffectFlu-like syndrome (fever, chills, myalgia)

Mechanism of ActionBlockade of viral RNA translation inside the cell

Classification and Production Methods

In medical practice, interferon (IFN) preparations are classified according to two main criteria: chemical-biological properties and production technology.

Based on chemical and biological properties, six types are distinguished. The most clinically significant are IFN-α (alpha), IFN-beta (beta), and IFN-γ (gamma). There are also IFN-δ (delta), IFN-ω (omega), and IFN-τ (tau).

By production method, two major groups of dosage forms are distinguished:

Natural preparations. These are obtained from leukocyte cultures isolated from donor blood. To trigger interferon synthesis, the cells are induced with a specific virus. This group includes IFN-α, IFN-β, and IFN-α-n1.
Recombinant preparations. These are products of modern genetic engineering. In laboratory conditions, plasmids containing the human interferon gene are inserted into bacterial strains, after which the bacteria synthesize the required glycoprotein. Examples of such agents include IFN-α-2a, IFN-α-2b, and IFN-α-1b.

Pharmacokinetics and Mechanism of Action

The pharmacokinetics of interferons have strict limitations. These drugs are completely inactive when taken orally, as their protein structure is rapidly degraded in the gastrointestinal tract. Therefore, they are administered exclusively parenterally (subcutaneously, intramuscularly, or intravenously) or applied topically.

The initial stage of drug action involves the interaction of the molecule with specific receptors located on the target cell membrane. This binding triggers a complex cascade of intracellular reactions that leads to the induction of various enzyme syntheses.

At the cellular level, interferons exert three main effects: antiviral, antitumor, and immunomodulatory.

Antiviral mechanism: interferon activates a specific enzyme that directly inhibits (blocks) the translation of viral RNA. This prevents further viral replication inside the cell.
Effect on the cell cycle: the drugs exert strict control over cell proliferation (division), regulate cell differentiation, and can induce apoptosis (programmed cell death) in defective structures.
Immune response: activation of immune effectors—macrophages—occurs, alongside a significant increase in lymphocyte cytotoxicity.

Clinical Application

Indications for prescription depend on the specific type of interferon and its dosage form.

IFN-α (alpha) preparations have the widest spectrum of application. In infectious disease practice, they are prescribed for viral hepatitis B and C, HIV infection, and human papillomavirus infection. In oncology, they have proven effective in treating Kaposi sarcoma, various leukemias, and melanoma.
IFN-β (beta) preparations have found their niche in neurology. They are used as potent immunomodulators in the complex management of multiple sclerosis.
IFN-γ (gamma) preparations (e.g., interferon gamma-1b) are used to treat severe pathologies, particularly chronic granulomatous disease.
Local and topical application covers various types of IFN:
Ophthalmology: treatment of herpetic eye lesions (using drops and subconjunctival injections).
Dermatovenerology: management of herpes simplex (localized on the skin, mucous membranes, and genitals) and shingles. Special hydrogel-based ointments are used for this.
Respiratory infections: prevention and treatment of influenza and ARVI using intranasal drops.

Side Effects

Despite their high efficacy, interferon therapy is characterized by a wide range of side effects. The most frequent adverse event is flu-like syndrome.

In addition, the drugs can exert negative effects on various organ systems:

Central Nervous System (CNS): patients frequently complain of dizziness, visual disturbances, insomnia, and tremor. In severe cases, confusion, depression, and paresthesia may develop.
Gastrointestinal Tract (GIT): nausea and pronounced loss of appetite are characteristic.
Hematology and Kidneys: transient leukopenia and proteinuria may be observed in laboratory tests.
Cardiovascular System: symptoms of heart failure may appear.
Other reactions: dermatological manifestations (skin rash, itching, alopecia), epistaxis, and temporary impotence.

Mnemonic

To remember the main indications of the three major types, use this association: Alpha — Attacks viruses and tumors (hepatitis, melanoma), Beta — Blocks autoimmune aggression (multiple sclerosis), Gamma — Granulomatous disease.

Frequently asked questions

Which specific drugs belong to the group of recombinant interferons?

Recombinant interferon preparations obtained by genetic engineering include:

Interferon alfa-2a
Interferon alfa-2b
Interferon alfa-1b
Recombinant interferon alfa products
Recombinant interferon beta products

What specific enzymes are synthesized in the cell under the action of interferons?

Under the action of interferons, the cell initiates the synthesis of key effector proteins and specific enzymes that provide the antiviral effect:

2'-5'-Oligoadenylate synthetase (Oligoadenylate-2'-5'-synthetase) — activates cellular endoribonuclease (RNase L), which cleaves viral RNA
Protein kinase R (PKR) (Protein kinase P1) — a serine-threonine kinase that phosphorylates translation initiation factor eIF-2 and cellular enzymes, blocking protein synthesis
Mx protein (Mx protein) — binds to viral RNA polymerase, halting its replication

Which exact receptors do interferons bind to on the target cell membrane?

Interferons bind to specific membrane receptors on target cells, which are subdivided into families depending on the interferon type:

Type I interferon receptor (IFNAR) — consists of two molecular chains: IFNAR1 (or β1) and IFNAR2 (or β2), to which alpha and beta interferons bind simultaneously
Type III interferon receptor — represented by two molecules: IFNAR1 and IL10R2, containing a chain shared with the interleukin-10 receptor

What changes in blood tests can interferon therapy cause?

Interferon therapy can lead to alterations in blood parameters, among which the development of transient leukopenia is noted as a hematological adverse effect on the hematopoietic system.

Why are interferons not available in oral tablets?

Interferons have a protein structure (they are glycoproteins); therefore, when taken orally, they are completely degraded by gastrointestinal enzymes and lose their pharmacological activity.

What is the difference between natural and recombinant interferons?

Natural preparations are obtained from human donor leukocytes after stimulation with an inducing virus. Recombinant preparations are produced using genetic engineering methods by cultivating bacterial strains with an inserted human interferon gene plasmid.

How exactly does interferon stop a viral infection?

It does not destroy the virus directly. The drug binds to cell receptors and induces the synthesis of a specific enzyme that blocks viral RNA translation, making viral replication impossible.

Go deeper

The process of obtaining natural interferons from donor leukocyte cultures.
Technology for cultivating bacterial strains to produce recombinant IFNs.
Mechanisms of cell cycle control, proliferation, and apoptosis induction.
Specific enzymes inhibiting viral RNA translation.
Application of IFN-alpha preparations in oncology (melanoma, Kaposi sarcoma, leukemias).