peginterferon beta-1a

(peg-in-ter-feer-on bay-ta ),

Plegridy

(trade name)

Classification

Therapeutic: immune modifiers
Pharmacologic: interferons
Pregnancy Category: C

Indications

Treatment of relapsing forms of multiple sclerosis.

Action

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 effects

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

Pharmacokinetics

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)

ROUTE	ONSET	PEAK	DURATION
subcutaneous	within one mo	24–36 wk	unknown

Contraindications/Precautions

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 ↑); Geriatric: Safe and effective use in geriatric patients has not been established; Obstetric: Use during pregnancy only if potential benefit justifies potential fetal risk; Lactation: Use cautiously if breastfeeding; Pediatric: Safe and effective use in children has not been established.

Adverse Reactions/Side Effects

Central nervous system

seizures (life-threatening)
suicidal ideation (life-threatening)
headache
depression (most frequent)
weakness

Cardiovascular

HF (life-threatening)

Gastrointestinal

hepatotoxicity (life-threatening)
nausea
vomiting

Dermatologic

pruritus

Hematologic

↓ peripheral blood counts

Local

injection site pain/pruritus/reactions (most frequent)

Musculoskeletal

arthralgia (most frequent)
myalgia (most frequent)

Miscellaneous

allergic reactions including anaphylaxis (life-threatening)
autoimmune disorders (life-threatening)
chills (most frequent)
fever (most frequent)
flu-like symptoms (most frequent)

Interactions

Drug-Drug interaction

↑ myelosuppression may occur with other myelosuppressives including antineoplastics. Concurrent use of hepatotoxic agents may ↑ the risk of hepatotoxicity (↑ liver enzymes). Avoid concommitant use with immunomodulating natural products such as astragalus, echinacea, and melatonin

Route/Dosage

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

Availability

Solution for subcutaneous injection in prefilled pens and syringes: 63 mcg/0.5 mL, 94 mcg/0.5 ml, 125 mcg/0.5 mL

Nursing implications

Nursing assessment

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 Nursing Diagnoses

Deficient knowledge, related to medication regimen (Patient/Family Teaching)

Implementation

Administer prophylactic analgesics and/or antipyretics to prevent or minimize flu-like symptoms.
Subcutaneous: 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.
Advise patient to notify health care professional if pregnancy is planned or suspected or if breastfeeding.

Evaluation/Desired Outcomes

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