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Plegridy Side Effects

Generic name: peginterferon beta-1a

Medically reviewed by Last updated on Oct 28, 2023.

Note: This document contains side effect information about peginterferon beta-1a. Some dosage forms listed on this page may not apply to the brand name Plegridy.

Applies to peginterferon beta-1a: solution.

Serious side effects of Plegridy

Along with its needed effects, peginterferon beta-1a (the active ingredient contained in Plegridy) 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

Less common


Other side effects of Plegridy

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

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.