Endocrine / Immunology
Interferons
Immune-signalling protein therapies — Injected versions of natural immune-signalling proteins used in some cancers, infections and multiple sclerosis.
Education and reference only. This is a plain-language class overview — it deliberately contains no doses. Always check the current Summary of Product Characteristics (SmPC), the BNF and your local formulary before prescribing or administering any medicine.
Quick answer
What is Interferons?
Interferons are manufactured copies of proteins the immune system makes naturally to fight viruses and abnormal cells. Given as injections, they are used in relapsing multiple sclerosis, certain cancers and some infections to modify the immune response.
- How it works: Natural interferons are signals released by cells to alert and activate the immune system against viruses and tumours, and to regulate inflammation.
- In practice: In practice interferons are laboratory-made versions of natural immune messenger proteins, given by injection in selected conditions — beta interferons in relapsing multiple sclerosis, and alpha interferons in certain cancers and some viral infections (their role in hepatitis has largely been replaced by better-tolerated tablets).
What it is
Interferons are manufactured copies of proteins the immune system makes naturally to fight viruses and abnormal cells. Given as injections, they are used in relapsing multiple sclerosis, certain cancers and some infections to modify the immune response.
How it works
Natural interferons are signals released by cells to alert and activate the immune system against viruses and tumours, and to regulate inflammation. The medicines supply these signals in larger, sustained amounts — slowing relapses in multiple sclerosis, helping the immune system control certain cancers, and suppressing some viruses. The same powerful immune signalling causes the flu-like and mood effects.
In practice
In practice interferons are laboratory-made versions of natural immune messenger proteins, given by injection in selected conditions — beta interferons in relapsing multiple sclerosis, and alpha interferons in certain cancers and some viral infections (their role in hepatitis has largely been replaced by better-tolerated tablets). They are specialist treatments, and their use is shaped by a very characteristic side-effect profile. Flu-like symptoms — fever, aches, chills and fatigue after each injection — are almost universal early on, eased by timing doses in the evening, paracetamol cover and gradual dose build-up, and usually settling with time. Beyond that, the important effects are on blood counts, liver function and thyroid, and notably mood: interferons can cause or worsen depression, so mental-health history is considered and low mood is actively asked about and acted on. They are generally avoided in significant depression, decompensated liver disease and pregnancy. Injection-site reactions are common with the subcutaneous forms. Regular blood tests track marrow, liver and thyroid effects throughout.
Examples
Practical use
How to take it & use it well
- These treatments are given by injection, and your team will show you or a carer how to inject it safely, rotating between different sites so the skin has time to recover.
- Many people find it helps to inject in the evening and take paracetamol around the time of the injection, as this lessens the flu-like aches and fever that often follow.
- Store the injections as instructed, usually in the fridge, and let a dose reach a comfortable temperature before injecting, never using it if it looks cloudy, discoloured or has been frozen.
- Tell your team straight away if you notice low mood, anxiety or thoughts of harming yourself, as these treatments can affect mood and any change must be taken seriously.
- Keep all your blood tests, as these check your blood counts, liver and thyroid, which can be affected and may need the treatment adjusting.
- Report any injection-site redness, swelling or breakdown, and any new or worsening symptoms such as breathlessness or persistent fever, rather than waiting until your next appointment.
Common uses
- Relapsing multiple sclerosis (beta interferon)
- Certain cancers and viral infections (alpha interferon)
- Selected specialist immune indications
Monitoring
- Full blood count, liver function and thyroid function regularly
- Mood and mental health
- Disease response and injection-site reactions
Weighing it up
Advantages & disadvantages
Advantages
- They can control certain serious conditions, including some chronic infections, cancers and multiple sclerosis.
- In multiple sclerosis, some can reduce how often relapses happen and slow the build-up of disability.
- They harness and direct the immune system to fight disease rather than relying on a separate chemical attack.
- They are well established, with long experience of their use and how to manage their effects.
- Many people learn to self-inject at home, fitting treatment around their own routine.
Disadvantages
- Flu-like symptoms such as fever, aches, chills and tiredness are common, especially after each injection.
- They can cause or worsen low mood and depression, which must be watched for and reported.
- They can lower blood counts and affect the liver and thyroid, so regular monitoring is essential.
- Injection-site reactions, including redness, soreness and occasionally skin breakdown, are common.
- Because they are injections given over a long period, they ask a lot of commitment and can be wearing.
Key safety principles
What to watch for
- Flu-like symptoms after injections are very common early on — ease with evening dosing, paracetamol and gradual build-up; they usually settle.
- Can cause or worsen depression — mental-health history matters and low mood must be reported and acted on.
- Affects blood counts, liver and thyroid — needs regular monitoring; avoided in significant depression, decompensated liver disease and pregnancy.
Key interactions
What to avoid or check alongside
- They can add to the effects of other medicines that lower blood counts, so combinations need careful monitoring.
- Drinking alcohol adds to the strain on the liver, which these treatments can already affect, so it is best limited.
- Other medicines that can affect mood should be reviewed, as interferons themselves can lower mood.
- They can change how some other medicines are handled by the liver, so your full treatment list should be checked.
- Tell your team about every medicine and supplement you take, as several can add to effects on blood, liver or thyroid.
Patient & carer advice
- Flu-like aches and fever after injections are common at first and tend to improve — taking it in the evening and using paracetamol helps
- Tell us straight away if your mood drops, as this medicine can affect it
- Keep up your blood tests so we can watch your liver, thyroid and blood counts
Answers
Interferons: frequently asked questions
Why do I feel like I have flu after each injection?
Flu-like symptoms such as fever, aching and chills are one of the most common effects of interferon treatment, particularly in the hours after an injection. Injecting in the evening and taking paracetamol around that time often helps, and the reaction tends to ease as your body gets used to treatment.
Can interferon treatment affect my mood?
Yes. These treatments can cause or worsen low mood, anxiety and, in some people, depression. This is important to take seriously: tell your team, family or a trusted person straight away if your mood changes, and seek urgent help if you ever have thoughts of harming yourself.
Why do I need so many blood tests on interferon?
Interferons can lower your blood counts and affect your liver and thyroid, often without obvious symptoms at first. Regular blood tests catch these changes early so your treatment can be adjusted before any problem becomes serious.
How should I store my interferon injections?
Most are kept in the fridge and must not be frozen, but always follow the specific advice for your product. Let a dose come to a comfortable temperature before injecting, and never use one that looks cloudy, discoloured or damaged. Ask your pharmacist if you are unsure.
What should I do about the sore lumps where I inject?
Redness, soreness and lumps at injection sites are common. Rotating between different sites, letting the dose warm up first and using good technique all help. Tell your team if the skin breaks down, becomes very painful or does not heal, as the plan may need adjusting.
Authoritative sources
Always verify against the source
This overview is for orientation. For doses, interactions, contra-indications and the full monograph, use:
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