Pharmacology · Class
Interferons !
Protein medicines copied from the body's antiviral signals. Once central for hepatitis, they are now used mainly in multiple sclerosis and rare diseases.
Updated 2026-11-01
What they are
Recombinant versions of human interferons. Interferon alfa (and its pegylated forms, injected weekly) treated hepatitis B and C and some cancers; direct-acting antivirals have largely replaced it for hepatitis C. Interferon beta is a treatment for relapsing multiple sclerosis, and interferon gamma reduces infections in chronic granulomatous disease.
Mechanism of action
Interferons bind receptors on the cell surface and activate the JAK-STAT pathway. A STAT complex enters the nucleus and switches on dozens of genes that create an antiviral state: 2'-5' oligoadenylate synthetase activates RNase L, which cuts RNA, and a protein kinase phosphorylates eIF-2 and stops protein synthesis. They also raise MHC class I expression and shape the immune response.
Target: Interferon receptors (IFNAR1/IFNAR2 for type I; IFNGR1/IFNGR2 for interferon gamma)
Drugs in this class
- Interferon alfaAn injected protein that switches on antiviral defences. Once central for hepatitis B and C, it causes flu-like…Type I interferon receptor (IFNAR1/IFNAR2)
- Interferon betaAn injected immunomodulator for relapsing multiple sclerosis. It reduces relapses but does not cure the disease.Type I interferon receptor (IFNAR1/IFNAR2)
- Interferon gammaAn injected immune activator that reduces serious infections in chronic granulomatous disease and slows severe…Interferon gamma receptor (IFNGR1/IFNGR2)
Others in the class
- Peginterferon alfa-2a
- Peginterferon alfa-2b
- Peginterferon beta-1a
- Ropeginterferon alfa-2b
Test yourself
Think of the answer, then tap the question to see it.
Which signalling pathway do interferons activate?
The JAK-STAT pathway, which switches on genes that create an antiviral state.
Which psychiatric adverse effect is most important with interferon alfa?
Depression, which can include suicidal thoughts.
Which interferon is used in relapsing multiple sclerosis, and which in chronic granulomatous disease?
Interferon beta in multiple sclerosis; interferon gamma in chronic granulomatous disease.
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 63 (McGraw Hill, 2023); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.