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Plegridy Side Effects

Generic Name: peginterferon beta-1a

Note: This page contains side effects data for the generic drug peginterferon beta-1a. It is possible that some of the dosage forms included below may not apply to the brand name Plegridy.

In Summary

Common side effects of Plegridy 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

As well as its needed effects, peginterferon beta-1a (the active ingredient contained in Plegridy) may cause unwanted side effects that require medical attention.

Major Side Effects

If any of the following side effects occur while taking peginterferon beta-1a, check with your doctor immediately:

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

Minor Side Effects

Some peginterferon beta-1a side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned 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.

It is possible that some side effects of Plegridy may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.