peginterferon beta-1a


peg-in-ter-feer-on bay-ta

Trade Name(s)

  • Plegridy

Ther. Class.
immune modifiers

Pharm. Class.


Relapsing forms of multiple sclerosis, including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease.


Antiviral and immunoregulatory properties produced by interacting with specific receptor sites on cell surfaces may explain beneficial effects. Produced by recombinant DNA technology. Pegylation prolongs duration of action.

Therapeutic Effect(s):

Reduced incidence of relapse (neurologic dysfunction) and slowed physical disability.


Absorption: Absorption follows subcutaneous administration.

Distribution: Unknown.

Metabolism and Excretion: Undergoes catabolism; excretion is mainly renal.

Half-life: 78 hr.

TIME/ACTION PROFILE (reduction in relapse rate)

subcutaneouswithin one mo24–36 wkunknown


Contraindicated in:

  • Hypersensitivity to natural or recombinant interferon beta or peginterferon.

Use Cautiously in:

  • History of depression or suicidal ideation;
  • History of seizures;
  • Renal impairment (risk of adverse reactions may be ↑);
  • OB:  Use during pregnancy only if potential maternal benefit justifies potential fetal risk;
  • Lactation: Use cautiously if breast feeding;
  • Pedi:  Safety and effectiveness not established;
  • Geri:  Safety and effectiveness not established.

Adverse Reactions/Side Effects

CNS: SEIZURES, SUICIDAL IDEATION, headache, depression, weakness


Derm: pruritus

GI: HEPATOTOXICITY, nausea, vomiting


Local: injection site pain/pruritus/reactions

MS: arthralgia, myalgia


* CAPITALS indicate life-threatening.
Underline indicate most frequent.



  • ↑ myelosuppression may occur with other  myelosuppressives  including  antineoplastics.
  • Concurrent use of  hepatotoxic agents  may ↑ the risk of hepatotoxicity (↑ liver enzymes).

Drug-Natural Products:

Avoid concommitant use with  immunomodulating natural products such as  astragalus,  echinacea, and  melatonin .


SC (Adults): 63 mcg initially, followed by 94 mcg on day 15, then 125 mcg every 14 days.


Solution for injection (prefilled pens and prefilled syringes): 63 mcg/0.5 mL, 94 mcg/0.5 mL, 125 mcg/0.5 mL


  • Assess frequency of exacerbations of symptoms of multiple sclerosis periodically during therapy.
  • Monitor patient for signs of depression during therapy. If depression occurs, notify health care professional immediately.
  • Monitor for injection site reactions (erythema, pain, pruritus, edema, bruising, drainage, necrosis). Avoid injecting near area of reaction.
  • Monitor patient with significant cardiac disease for worsening symptoms during initiation and periodically during therapy.

Lab Test Considerations: Monitor serum AST, ALT and bilirubin periodically during therapy.

  • Monitor CBC with differential and platelet counts periodically during therapy. May cause anemia, ↓ lymphocyte, ↓ neutrophil, and ↓ platelet counts.

Potential Diagnoses


  • Administer prophylactic analgesics and/or antipyretics to prevent or minimize flu-like symptoms.
  • SC Inject subcut in abdomen, back of upper arm, and thigh every 14 days; rotate sites. Prefilled pens are for single dose; discard after use.

Patient/Family Teaching

  • Instruct patient in correct technique for injection and care and disposal of equipment. Avoid injecting into areas of skin irritation, redness, bruising, infection, or scarring. Check injection site 2 hr after injection for redness, swelling, and tenderness. Notify health care professional if skin reaction does not clear in a few days. Caution patient not to reuse needles or syringes and provide patient with a puncture-resistant container for disposal.
  • Instruct patient to take medication as directed; do not change dose or schedule without consulting health care professional. Advise patient to read  Medication Guide  prior to starting therapy and with each Rx refill in case of changes.
  • Inform patient that flu-like symptoms (headache, fever, chills, myalgia, sweating, malaise, tiredness) may occur during therapy. Acetaminophen may be used for relief of fever and myalgias. Flu-like symptoms are not contagious.
  • Advise patient to notify health care professional immediately if signs and symptoms of liver disease (yellowing of skin or whites of eyes, nausea, loss of appetite, tiredness, bleeding easily, confusion, sleepiness, dark colored urine, pale stools), depression, suicidal thoughts, seizures, allergic reactions (itching; swelling of face, eyes, lips, tongue, throat; trouble breathing; feeling faint; anxiousness; rash; hives) or autoimmune diseases (easy bleeding or bruising, thyroid gland problems, autoimmune hepatitis) occur.
  • Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
  • Rep:  Advise patient to notify health care professional if pregnancy is planned or suspected or if breast feeding. Encourage patients to enroll in Pregnancy Registery by calling 1-866-810-1462 or visiting

Evaluation/Desired Outcomes

Decrease in the frequency of relapse (neurologic dysfunction) in patients with relapsing-remitting multiple sclerosis.

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