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Peginterferon beta-1a Side Effects

In Summary

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: subcutaneous solution

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 or sore throat
  • 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 and pains
  • muscle cramps
  • pale, clammy skin
  • runny nose
  • shivering
  • sweating
  • thirst
  • trouble sleeping
  • unusual tiredness or weakness
  • vomiting
Less common
  • Dark urine
  • decreased appetite
  • general feeling of tiredness or weakness
  • itching skin
  • light-colored stools
  • stomach or abdominal pain
  • yellow eyes or skin
  • Difficulty with swallowing
  • hives or welts
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • redness of the skin
  • skin rash
  • tightness in the chest

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 stiffness
  • pain, redness, or sloughing of skin at the injection site

For Healthcare Professionals

Applies to peginterferon beta-1a: 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.

The most commonly reported adverse event leading to discontinuation was influenza-like illness (in less than 1% of patients).[Ref]


Frequency not reported: Decreased peripheral blood counts[Ref]


Common (1% to 10%): Increased ALT, increased AST, increased GGT (gamma-glutamyl-transferase)
Frequency not reported: hepatic injury[Ref]


Frequency not reported: Anaphylaxis allergic reactions[Ref]


Frequency not reported: Autoimmune disorders[Ref]


Very common (10% or more): Injection site erythema (up to 62%), influenza like illness (up to 47%), pyrexia (up to 45%), chills (up to 17%), injection site pain (up to 15%), injection site pruritus (up to 13%)
Common (1% to 10%): Injection site edema, injection site warmth, injection site hematoma, injection site rash[Ref]


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

Nervous system

Very common (10% or more): Headache (up to 44%)
Frequency not reported: Seizures[Ref]


Very common: Asthenia (13%)
Common (1% to 10%): Increased body temperature, hyperthermia, pain[Ref]


Frequency not reported: Depression, suicide[Ref]


1. "Product Information. Plegridy (peginterferon beta-1a)." Biogen Idec Inc, Cambridge, MA.

Some side effects of peginterferon beta-1a may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

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