Plegridy vs. Avonex

Are Plegridy and Avonex the Same Thing?

Plegridy (peginterferon beta-1a) Autoinjector and Avonex (interferon beta-1a) are forms of interferon beta-1a used to treat patients with relapsing forms of multiple sclerosis.

Side effects of Plegridy and Avonex that are similar include injection site reactions (redness, itching, pain, swelling, warmth, rash, bruising).

Side effects of Plegridy that are different from Avonex include flu-like illness, fever, headache, muscle or joint pain, chills, weakness, nausea, and vomiting.

Side effects of Avonex that are different from Plegridy include dizziness, stomach pain, and runny or stuffy nose.

Plegridy may interact with other drugs.

Avonex may interact with acetaminophen, cancer medications, tuberculosis medications, birth control pills or hormone replacement therapy, methotrexate, arthritis medications, antibiotics, HIV/AIDS medications, cholesterol medications, ACE inhibitors, nonsteroidal anti-inflammatory drugs (NSAIDs), and seizure medications.

What Are Possible Side Effects of Plegridy?

Common side effects of Plegridy include:

  • injection site reactions (redness, itching, pain, swelling, warmth, rash, bruising),
  • flu-like illness,
  • fever,
  • headache,
  • muscle or joint pain,
  • chills,
  • weakness,
  • nausea, and
  • vomiting

What Are Possible Side Effects of Avonex?

Common side effects of Avonex include:

  • injection site reactions (pain, swelling, or redness),
  • dizziness,
  • stomach pain, or
  • runny or stuffy nose.

Flu-like symptoms such as headache, fatigue, fever, chills, and muscle aches may occur when you first start Avonex. These symptoms usually last about a day after the shot and improve or go away after a few months of continued use of Avonex. Some patients using interferon medications such as Avonex have become depressed or had suicidal thoughts. Tell your doctor immediately if this occurs. Tell your doctor right away if you have any serious side effects of Avonex including:

  • mental/mood changes (e.g., depression, thoughts of suicide, new or worsening psychiatric symptoms),
  • hair loss,
  • vision changes,
  • persistent fatigue,
  • numbness/tingling/swelling of the hands/ankles/feet,
  • muscle weakness,
  • trouble breathing,
  • sudden weight gain,
  • gradual change in weight (without a change in diet or exercise),
  • cold or heat intolerance,
  • slow/fast/irregular heartbeat,
  • easy bleeding or bruising,
  • signs of infection (e.g., fever, persistent sore throat),
  • yellowing eyes or skin,
  • persistent nausea or vomiting,
  • stomach or abdominal pain, or
  • dark urine.

What Is Plegridy?

Plegridy (peginterferon beta-1a) Autoinjector is an interferon beta-1a used to treat patients with relapsing forms of multiple sclerosis.

What Is Avonex?

Avonex (Interferon beta-1a) is a 166 amino acid glycoprotein used to treat relapsing multiple sclerosis (MS). Avonex will not cure MS, it will only decrease the frequency of relapse symptoms.

What Drugs Interact With Plegridy?

Tell your doctor all medications and supplements you use. During pregnancy, Plegridy should be used only if prescribed. It is unknown if this drug passes into breast milk. Consult your doctor before breastfeeding.

What Drugs Interact With Avonex?

The recommended dosage of Avonex is 30 mcg injected intramuscularly once a week. This medication is intended for use under the guidance and supervision of a physician. Patients may self-inject only if their physician determines it is appropriate and after proper training in intramuscular injection technique.

How Should Plegridy be Taken?

The recommended dosage of Plegridy is 125 micrograms injected subcutaneously every 14 days.

How Should Avonex be Taken?

The recommended dose for Avonex is 7 mg or 14 mg taken orally, once daily, with or without food.


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Biogen. Plegridy Product Information

Biogen. Avonex Product Information

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