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Plegridy 63 micrograms solution for inject pre‑filled pen – patient leaflet, side effects, dosage

Last updated: · Text from the MHRA, as of · About this document

Medicine strength:
63/94 micrograms
Contains active substance:
Similar medicines:

Patient leaflet - Plegridy 63/94 micrograms solution for injection in Pre Filled pen

What Plegridy is used for

This medicine is used to treat relapsing‑remitting m sclerosis (MS) in adults aged 18 or over.

ultiple

MS is a long term illness that affects the central nervo system (CNS), including the brain and spinal cord, in

us

which

the body’s immune system (its natural defences) dam the protective layer (myelin) that surrounds the nerve brain and spinal cord. This disrupts the messages bet brain and other parts of the body, causing the sympt MS. Patients with relapsing‑remitting MS have period the disease is not active (remission) in between flare‑symptoms (relapses).

ages

s in the ween the oms of

s when ups of

Everyone has their own set of MS symptoms. These include:

can

Feeling off‑balance or light headed, walking proble stiffness and muscle spasms, tiredness, numbness i face, arms or legs

ms,

n the

Acute or chronic pain, bladder and bowel problems problems and problems with vision

, sexual

Difficulty thinking and concentrating, depression.

How Plegridy works

Plegridy seems to work by stopping the body’s immu system from damaging your brain and spinal cord. Thi help to reduce the number of relapses that you have and down the disabling effects of MS. Treatment with Plegrid to prevent you from getting worse, although it will not cu

ne

s can

slow

y can help re MS.

peginterferon beta-1a

2. What you need to know b use Plegridy

efore you

Do not use Plegridy

  • If you are allergic to peginterferon be

    ta‑1a, interferon is medicine (listed in toms of an allergic

    beta‑1a or any of the ingredients of th section 6). See section 4 for the symp reaction.

  • If you have severe depression or thin

    k about committing suicide.

Warnings and precautions

Talk to your doctor if you have ever had

:

  • Depression or problems affecting you

    r mood

  • Thoughts about committing suicide

    Your doctor may still prescribe Pleg it’s important to let your doctor kno depression or any similar problems mood in the past.

    ridy for you, but w if you have had affecting your e before injecting ns listed below.

Talk to your doctor, pharmacist or nurs

Plegridy if you have any of the conditio They may get worse while using Plegrid

y:

  • Serious liver or kidney problems
  • Irritation at an injection site, which ca

    n lead to skin and tissue damage (injection site necro are ready to inject, carefully follow the section 7 “Instructions for injecting Ple at the end of this leaflet. This is to redu injection site reactions.

    sis). When you instructions in gridy pre-filled pen”, ce the risk of

  • Epilepsy or other seizure disorders, n

    ot controlled by medicine

  • Heart problems, which can cause sym

    ptoms such as chest pain (angina), particularly after ankles, shortness of breath (congestiv an irregular heartbeat (arrhythmia).

    any activity; swollen e heart failure); or

  • Thyroid problems platelets, which n, or bleeding
  • A low number of white blood cells or can cause an increased risk of infectio

Other things to consider when using Pl

egridy

  • You will need blood tests to determine y

    our numbers of vels of liver enzymes. t using Plegridy, as been initiated even if you have no will be in addition to nitor your MS.

    blood cells, blood chemistry and your le These will be performed before you star regularly after treatment with Plegridy h and then periodically during treatment, particular symptoms. These blood tests the tests which are normally done to mo

  • The functioning of your thyroid gland

    will be checked ary by your doctor

    regularly or whenever thought necess for other reasons.

  • Blood clots in the small blood vessels

    may occur during ld affect your

    your treatment. These blood clots cou kidneys. This might happen several we years after starting Plegridy. Your doc check your blood pressure, blood (pla function of your kidneys.

    eks to several tor may want to telet count) and the

If you accidentally prick yourself or someo needle in Plegridy, the area affected shoul immediately with soap and water and a do should be contacted as soon as possible.

ne else with the d be washed ctor or nurse

Children and adolescents

Plegridy should not be used in children an because it is yet to be established whether them and whether it would be safe.

d adolescents it would work for

Other medicines and Plegridy

Plegridy should be used carefully with me broken down in the body by a group of pr “cytochrome P450” (e.g. some medicines depression).

dicines that are oteins called used for epilepsy or

Tell your doctor or pharmacist if you are recently taken or might take any other m

taking, have edicines, especially those used to treat epilepsy or depressi medicines obtained without a prescripti

on. This includes any on.

Sometimes you will need to remind other h professionals that you are being treated wi example, if you are prescribed other medic a blood test. Plegridy may affect the other test result.

ealthcare th Plegridy. For ines, or if you have medicines or the

Pregnancy and breast‑feeding

If you are pregnant or breast‑feeding, thin pregnant or are planning to have a baby, a pharmacist for advice before taking this m No harmful effects on the breastfed newbo anticipated. Plegridy can be used during b

k you may be sk your doctor or edicine.

rn/infant are reast‑feeding.

Driving and using machines

Plegridy has no or negligible influence on t and use machines.

he ability to drive

Plegridy contains sodium

This medicine contains less than 1 mmol so is to say it is essentially “sodium‑free”.

dium (23 mg), that

3. How to use Plegrid

y

Always use this medicine exact has told you. Check with your d not sure.

ly as your doctor or pharmacist octor or pharmacist if you are

The usual dose

One injection of Plegridy 125 m two weeks). Try to use Plegridy day, every time you inject.

icrograms every 14 days (every at the same time on the same

Starting Plegridy

If you are new to Plegridy, your d gradually increase your dose so t of Plegridy before taking the full an Initiation Pack containing you pen with Plegridy 63 microgram with Plegridy 94 micrograms (fo

octor may advise you to hat you can adjust to the effects dose. You will be provided with r first 2 injections: one orange s (for day 0) and one blue pen r day 14).

After that you will be provided containing grey pens with Pleg 28 and then every two weeks).

with a maintenance pack ridy 125 micrograms (for day

Read the instructions in section

7 “Instructions for injecting

Plegridy pre-filled pen” at the e start using Plegridy.

nd of this leaflet before you

Use the record table printed on Initiation Pack to keep a track o

the inside of the lid of the f your injection dates.

Injecting yourself

Plegridy is to be injected under injection). Alternate the sites yo the same injection site for cons You can inject Plegridy yourself doctor, if you have been trained

the skin (subcutaneous u use for injections. Do not use ecutive injections.

without the help of your how to do this.

Read and follow the advice g section 7 “Instructions for inj before you start.

iven in the instructions in ecting Plegridy pre-filled pen”

If you have trouble handling nurse who may be able to he

the pen, ask your doctor or lp.

How long to use Plegridy

Your doctor will tell you how lo Plegridy. It is important to cont Do not make changes unless yo

ng you need to keep using inue using Plegridy regularly. ur doctor tells you.

If you use more Plegridy t

han you should

You must only inject Plegridy o

nce every 2 weeks.

If you have used more than o

ne injection of Plegridy in a

7‑day period, contact your d

octor or nurse straight away.

If you forget to use Plegri

dy

You need to inject Plegridy onc schedule helps to deliver the tr

e every 2 weeks. This regular eatment as evenly as possible.

If you do miss your usual day, in carry on as usual. However, do a 7‑day period. Do not use two missed injection.

ject as soon as you can and not inject more than once in injections to make up for a

If you have any further quest medicine, ask your doctor, ph

ions on the use of this armacist or nurse.

4. Possible side effec

ts

Like all medicines, this medicin although not everybody gets th

e can cause side effects, em.

Serious side effects Liver problems

(common - may affect up to 1 If you get any of these sympt

in 10 people)

oms:

  • Yellowing of your skin or th

    e whites of your eyes

  • Itching all over
  • Feeling sick, being sick (na

    usea and vomiting)

  • Easy bruising of the skin iately. They may be signs of a

    Contact a doctor immed possible liver problem.

Depression

(common - may affect up to 1 If you:

in 10 people)

  • Feel unusually sad, anxious

    or worthless or

  • Have thoughts about suici

    de

    Contact a doctor immed

    iately.

Serious allergic reaction

(uncommon - may affect up t If you get any of these:

o 1 in 100 people)

  • Difficulty breathing
  • Swelling around the face (l

    ips, tongue or throat)

  • Skin rashes or redness

    Contact a doctor immed

    iately.

Seizures

(uncommon - may affect up t If you have a seizure or a fit

o 1 in 100 people)

Contact a doctor immed

iately.

Injection site dam

age

(rare - may affect If you get any of t

up to 1 in 1,000 people)

hese symptoms:

  • Any break in th

    e skin together with swelling, inflammation around the injection site

    or fluid leaking

    Contact a do

    ctor for advice.

Kidney problems kidney function

including scarring that may reduce your

(rare - may affect If you get some o

up to 1 in 1,000 people)

r all of these symptoms:

  • Foamy urine
  • Fatigue
  • Swelling, partic

    ularly in the ankles and eyelids, and weight gain.

    Contact a do kidney probl

    ctor as they may be signs of a possible em.

Blood problems

(rare - may affect The following may blood vessels that thrombocytopeni syndrome). Symp bleeding, fever, ex

up to 1 in 1,000 people)

occur: Blood clots in the small can affect your kidneys (thrombotic c purpura or haemolytic uremic toms may include increased bruising, treme weakness, headache, dizziness or light‑headedness. blood and the fun

Your doctor may find changes in your ction of your kidneys.

If you get some o

r all of these symptoms:

  • Increased bruisi

    ng or bleeding

  • Extreme weakn

    ess

  • Headache, dizzi

    ness or light‑headedness

    Contact a do

    ctor immediately.

Other side effec Very common sid

ts e effects

(may affect more

than 1 in 10 people)

  • Flu‑like sympto

    ms. These symptoms are not really flu, can’t pass it on to anyone else.

    see below. You

  • Headache
  • Muscle pain (m

    yalgia)

  • Pain in your join

    ts, arms, legs or neck (arthralgia)

  • Chills
  • Fever
  • Feeling weak a

    nd tired (asthenia)

  • Redness, itchin

    g or pain around the place you have injected

    If any of thes

    e effects trouble you, contact a doctor.

Flu‑like symptoms

Flu‑like symptoms a

re more common when you first start using Plegridy. They injections. See belo symptoms if you ge

gradually get less as you keep using your w for simple ways to manage these flu‑like t them.

Three simple ways to

help reduce the impact of flu‑like symptoms: g of your Plegridy injection. The start and ptoms are different for every patient. On ymptoms begin approximately 10 hours last between 12 and 24 hours.

  1. 1. Consider the timin end of flu‑like sym average, flu‑like s after injection and
  2. 2.

    Take paracetamol

    or ibuprofen half an hour before your and continue to take paracetamol or duration of your flu‑like symptoms. Speak pharmacist about how much to take and t.

    Plegridy injection ibuprofen for the to your doctor or how long to take i

  3. 3.

    If you have a fever,

    drink plenty of water to keep you hydrated.

    Common side eff

    ects

    (may affect up to

    1 in 10 people)

    • Feeling or bein

      g sick (nausea or vomiting)

    • Hair loss (alope

      cia)

    • Itchy skin (pruri

      tus)

    • Increase in bod

      y temperature

    • Changes aroun

      d the place you have injected such as mation, bruising, warmth, rash or colour

      swelling, inflam change

    • Changes in you

      r blood which might cause tiredness or to fight infection

      reduced ability

    • Increases in live

      r enzymes in the blood (will show up in blood tests)

      If any of thes

      e effects trouble you, talk to your doctor.

Uncommon side e

ffects

(may affect up to

1 in 100 people)

  • Hives
  • Changes in you

    r blood which might cause unexplained ding.

    bruising or blee

    If any of thes

    e effects trouble you, talk to your doctor.

Frequency not kno

wn

(frequency cannot b

e estimated from the available data) rial hypertension: A disease of severe e blood vessels in the lungs resulting ressure in the blood vessels that carry heart to the lungs. Pulmonary arterial s been seen at various time points during ding several years after starting treatment beta‑products.

  • Pulmonary arte narrowing of th in high blood p blood from the hypertension ha treatment, inclu with interferon

Children (10 years o

f age and above) and adolescents

In clinical trials, som commonly in both a injection site, flu‑like

e side effects were reported very dults and children, e.g., redness at the symptoms, headache, and fever.

Reporti

ng of side effects

If you ge or nurse. this leafl national

t any side effects, talk to your doctor, pharmacist This includes any possible side effects not listed in et. You can also report side effects directly via the reporting system:

United K

ingdom

Yellow C Website: Yellow C

ard Scheme www.mhra.gov.uk/yellowcard or search for MHRA ard in the Google Play or Apple App Store

By repor informati

ting side effects you can help provide more on on the safety of this medicine.

In order doctor o number file. You you are a

to improve the traceability of this medicine, your r pharmacist should record the name and the lot of the product you have been given in your patient may also wish to make a note of these details in case sked for this information in the future.

5. Ho

w to store Plegridy

Keep this

medicine out of the sight and reach of children.

Do not u on the ca to the las

se this medicine after the expiry date which is stated rton and the label after “EXP”. The expiry date refers t day of that month.

Store i Only o

n the original package in order to protect from light. pen the pack when you need a new pen.

n a refrigerator (fridge), 2°‑8°C.

Store i

  • Do n

    ot freeze. Throw away any Plegridy that is dentally frozen.

    acci

Plegrid to 25°C

y can be kept outside a fridge at room temperature (up ) for up to 30 days but it must be kept away from light. s can be taken out of the fridge and then put back in dge more than once if you need to.

  • Pack a fri
  • Mak

    e sure the time the pens spend out of a fridge is no e than 30 days in total.

    mor

  • Thro

    w away any pen that is kept out of the fridge for e than 30 days.

    mor

  • If yo

    u are unsure of the number of days you have kept a out of the fridge, throw the pen away.

    pen

Do not

use this medicine if you notice any of the following: e pen is broken.

  • If th
  • If th

    e solution is coloured, cloudy or you can see particles ing in it.

    float

Do not house medici protec

throw away any medicines via wastewater or hold waste. Ask your pharmacist how to throw away nes you no longer use. These measures will help t the environment.

6. Con

tents of the pack and other information

What P

legridy contains

The activ

e ingredient is peginterferon beta‑1a.

Each 63 peginterf Each 94 peginterf Each 125 peginterf

microgram pre‑filled pen contains 63 micrograms of eron beta‑1a in 0.5 mL solution for injection. microgram pre‑filled pen contains 94 micrograms of eron beta‑1a in 0.5 mL solution for injection. microgram pre‑filled pen contains 125 micrograms of eron beta‑1a in 0.5 mL solution for injection.

The othe acid glac for inject

r ingredients are: Sodium acetate trihydrate, acetic ial, arginine hydrochloride, polysorbate 20 and water ions (see Section 2 “Plegridy contains Sodium”).

What P

legridy looks like and contents of the pack

Plegridy glass pre

is a clear and colourless solution for injection in a ‑filled pen with an attached needle.

Pack size

s:

  • The Ple

    gridy Initiation Pack contains one orange pre‑filled pen icrograms and one blue pre‑filled pen of 94 micrograms. 5 micrograms grey pens are provided in a pack ning either two or six pre‑filled pens.

    of 63 m

  • The 12 contai

Not all p

ack sizes may be marketed.

Marketin

g Authorisation Holder Manufacturer

Biogen N Prins Ma 1171 LP B

etherlands B.V. Biogen Netherlands B.V. uritslaan 13 Prins Mauritslaan 13 adhoevedorp 1171 LP Badhoevedorp

The Neth

erlands The Netherlands

For any i local rep

nformation about this medicine, please contact the resentative of the Marketing Authorisation Holder:

United K

ingdom

Biogen I ( +44 (0

dec Limited

) 1628 50 1000

This leafl

et was last revised in 01/2026

Instru

ctions overleaf

  1. 7.

    Instructions for injecting Plegridy p

    Caution! Do not remove the cap until you are read

How to Inject Plegridy

Read the instructions for use before you start using P prescription. There may be new information. This info doctor or nurse about your medical condition or your

Note:

  • Before you use the pen for the first time, your doc

    prepare and inject the pen.

  • The pen is for use under the skin only (subcutaneo
  • Each pen can be used once only.

    Do not share the pen with anyone else to avoid giv from them.

    Do not use more than 1 pen every 14 days (every 2 Do not use the pen if it has been dropped or is vis

    Dosage schedule

The Initiation Pack contains your first two injections to from a pack.

When Which dose

re‑filled pen y to inject.

legridy and each time you get a refill of your rmation does not take the place of talking to your treatment.

tor or nurse should show you or your carer how to us).

ing an infection to them or getting an infection weeks).

ibly damaged.

gradually adjust your dose. Choose the correct pen

Which pack

Step 4: Choose and clean your injection site a. Choose an injection site in your thigh, abdomen, or t

(see highlighted areas in Figure D).

  • If some areas are too difficult for you to reach, as trained to help you.

    Do not inject into an area of your body where the tattooed, infected, or scarred.

    Do not inject directly into your belly button.

b. Wipe your skin with an alcohol wipe.

Note: Do not touch or blow on this area again be c. Let your injection site dry on its own before injectin

Giving your injection

Step 5: Remove the Plegridy pen cap a. Pull the pen cap straight off and set it aside (see Fig

Your pen is now ready to inject.

Warning! Do not touch, clean, or manipulate the nee needle injury or the pen may lock.

Caution! Do not re‑cap your pen. This could lock the

he back of your upper arm k a carer who has been skin is irritated, red, bruised, fore giving your injection.

g your dose.

ure E).

dle cover. You could get a pen

Day 0

First injection 63 micrograms, choose

(63 micrograms)

Day 14

Second injectio 94 micrograms, choos

(94 micrograms)

Day 28 and

Full dose injecti 125 micrograms, c

then every two weeks after that (125 micrograms)

grey pen

Do not use more than one pen per 14‑day period (

:

orange pen

n:

e blue pen

Step 6: Give the injection a. Hold the pen over your injection site. Make sure you the injection status window (see Figure F).

  • You should hold the pen over your injection site a

Warning! Do not rest the pen on the injection site un This may cause the pen to accidently lock.

can see the green stripes in t 90o angle.

til you are ready to inject.

on:

hoose

every 2 weeks).

ction:

n site, the needle cover will lock to protect against e right way to throw away the used pen.

plaster to the injection site.

After the injection

After Use – Parts of your Plegridy pen (see Figure K):

Note: After the pen has been removed from the injectio needle injury. Do not re‑cap the pen.

Step 9: Dispose of used Plegridy pen

  • Check with your doctor, pharmacist or nurse about th Do not re‑cap the pen.

Step 10: Care for your injection site

  • If needed, apply a gauze pad or adhesive bandage or

Supplies needed for your Plegridy Pen inje

  • 1 Plegridy Pen (see Figure A)

Before use – Parts of Plegridy Pen (Figure A)

b. Firmly press and hold down the pen on your injectio clicking sounds start. This tells you that the injection c. Continue to hold the pen firmly down on your injecti sounds have stopped (see Figure H).

Do not lift your pen off your injection site until the c

n site. You will hear the is happening (see Figure G).

on site until the clicking licking sounds stop and you

Step 11: Check injection site

  • After 2 hours, check the injection site for redness, sw
  • If you have a skin reaction and it does not clear up in

    Record date and location

  • Record the date and location of each injection.
  • For the Initiation Pack injections, you can use the rec

    Initiation Pack.

    General warnings

    Do not reuse your Plegridy pen.

    Do not share your Plegridy pen.

  • Keep Plegridy pen and all medicines out of reach of

    Storage

  • Recommended storage is controlled refrigeration 2°C light.
  • If needed, Plegridy may be stored in the closed origin

    30 days.

  • Plegridy can be removed from and returned to the r of refrigeration at a temperature up to 25°C, should

elling, or tenderness.

a few days, contact your doctor or nurse.

ord table printed on the inside of the lid of the
children.
to 8°C in the closed original carton to protect from al carton without refrigeration up to 25°C for up to efrigerator if necessary. The total combined time out not exceed 30 days.

Caution! Do not remove the cap until you are read Re‑capping could cause the pen to lock.

Additional supplies which are not included in the pack (

Alcohol Wipe

Ga P

Figure B

Preparing for your injection

Step 1: Remove your pen from the fridge.

a. Remove your Plegridy pack from the fridge and sel

b. Close the pack and put back in the fridge after rem

c. Let the pen warm to room temperature for at leas

Do not use external heat sources, such as hot w

Step 2: Collect your supplies and wash your

a. Find a well‑lit, clean, flat surface to work on like a t

yourself, or receive, an injection.

b. Wash your hands with soap and water.

y to inject. If you remove the cap, do not re‑cap the pen.

see Figure B):

uze

ad

Adhesive Bandage ect the appropriate pen (dosage) from the pack.

oving one pen.

t 30 minutes.

ater, to warm your pen.

hands.

able. Collect all the supplies you will need to give

see green ticks in the injection status window.

Warning! If you do not hear clicking sounds or you injection status window after attempting to inject, th you may not have received your injection. You shoul nurse or pharmacist.

Step 7: Remove the Plegridy pen from your i a. After the clicking sound has stopped, lift the pen fro needle cover will extend to cover the needle and wil

  • If you see blood at your injection site, wipe it off w an adhesive bandage or plaster

Step 8: Check to make sure you received you a. Check the injection status window. You should see g b. Check the medicine window. You should see a yellow

do not see green ticks in the e pen may have locked and d then contact your doctor, njection site m your injection site. The l lock (see Figure I).

ith the gauze pad and apply r full dose of Plegridy (see Figure J)

reen ticks.

plunger.

Do not freeze or expose to high temperatures.

Step 3: Check your Plegridy pen (see Figure

a. Check the injection status window. You should see

b. Check the expiry date.

c. Check the medicine window and make sure the Ple

clear and colourless.

Do not use the pen if:

  • You do not see the green stripes in the inject
  • It is expired.
  • The liquid is coloured, cloudy or contains flo

Note: You might see air bubbles in the medicine window. not affect your dose.

Do not use the pen if it has been dropped or is visibly

C)

green stripes.

gridy medicine is ion status window.

ating particles.

This is normal and will damaged.

About this document

Source: MHRA - Medicines and Healthcare products Regulatory Agency (products.mhra.gov.uk) · Marketing authorisation: PLGB 22407/0017

Last revision stated in the text: January 2026 · MHRA data as of 13 October 2026

Found a mistake? Tell us on the contact page.

The information on this site does not replace the advice of a doctor or pharmacist.

Facts about Plegridy 63/94 micrograms solution for injection in Pre Filled pen

Active substance Peginterferon beta-1a
Strength 63/94 micrograms
Drug group (ATC)
  1. L Antineoplastic and immunomodulating agents
    1. L03 Immunostimulants
      1. L03A Immunostimulants
        1. L03AB Interferons
          1. L03AB13 peginterferon beta-1a
Marketing authorisation PLGB 22407/0017

Sources: the MHRA product information (products.mhra.gov.uk). Contains public sector information licensed under the Open Government Licence v3.0.