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Peginterferon beta-1a Side Effects

Medically reviewed by Last updated on May 29, 2022.


Commonly reported side effects of peginterferon beta-1a include: arthralgia, asthenia, fever, flu-like symptoms, headache, myalgia, chills, erythema at injection site, pain at injection site, and swelling at injection site. Other side effects include: suicidal ideation, hyperthermia, increased serum alanine aminotransferase, pruritus, vomiting, decreased white blood cell count, depression, increased serum aspartate aminotransferase, and increased body temperature. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to peginterferon beta-1a: solution

Side effects requiring immediate medical attention

Along with its needed effects, peginterferon beta-1a may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking peginterferon beta-1a:

More common

  • Blue-green to black skin discoloration
  • chills
  • cough
  • diarrhea
  • dizziness
  • extremely high fever or body temperature
  • fast, shallow breathing
  • fast, weak heartbeat
  • fever
  • general feeling of discomfort or illness
  • joint pain
  • muscle aches, cramps, and pains
  • pale, clammy skin
  • runny nose
  • seizures
  • shivering
  • sore throat
  • sweating
  • thirst
  • trouble sleeping
  • unusual tiredness or weakness
  • vomiting

Less common

  • Dark urine
  • decreased appetite
  • itching skin
  • light-colored stools
  • stomach pain
  • yellow eyes or skin


  • Chest tightness
  • difficulty with swallowing
  • hives or welts, skin rash
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • redness of the skin

Side effects not requiring immediate medical attention

Some side effects of peginterferon beta-1a may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  • Difficulty with moving
  • itching, rash, redness, soreness, swelling, or warmth at the injection site
  • lack or loss of strength
  • muscle aches, cramps, pains, or stiffness
  • pain, redness, or sloughing of the skin at the injection site

For Healthcare Professionals

Applies to peginterferon beta-1a: intramuscular solution, subcutaneous kit, subcutaneous solution


Frequency not reported: Congestive heart failure[Ref]


Common (1% to 10%): Pruritus[Ref]


Common (1% to 10%): Nausea, vomiting[Ref]


The most common side effects were injection site erythema, influenza-like illness, pyrexia, headache, myalgia, chills, injection site pain, asthenia, injection site pruritus, and arthralgia.[Ref]


Frequency not reported: Decreased peripheral blood counts[Ref]


Common (1% to 10%): Alanine aminotransferase increased, aspartate aminotransferase increased, gamma-glutamyl-transferase increased

Frequency not reported: hepatic injury[Ref]


Uncommon (0.1% to 1%): Anaphylaxis, angioedema, urticaria[Ref]


Very common (10% or more): Influenza like illness (47%)

Frequency not reported: Autoimmune disorders[Ref]


Very common (10% or more): Injection site erythema (62%), injection site pain (15%), injection site pruritus (13%)

Common (1% to 10%): Injection site edema, injection site warmth, injection site hematoma, injection site rash[Ref]


Very common (10% or more): Myalgia (19%), arthralgia (11%)[Ref]

Nervous system

Very common (10% or more): Headache (44%)

Uncommon (0.1% to 1%): Seizures[Ref]


Very common (10% or more): Pyrexia (45%), chills (17%), asthenia (13%)

Common (1% to 10%): Hyperthermia, pain[Ref]


Common (1% to 10%): Depression, suicide[Ref]

Frequently asked questions


1. "Product Information. Plegridy (peginterferon beta-1a)." Biogen Idec Inc (2014):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.