Betaseron

interferon beta-1a

Avonex, Rebif

interferon beta-1b

Betaferon (UK), Betaseron, Extavia

Pharmacologic class: Biological response modifier

Therapeutic class: Antiviral, immunoregulator

Pregnancy risk category C

Action

Binds and competes with specific receptors on cell surface, inducing various interferon-induced gene products. Also inhibits proliferation of T cells.

Availability

Lyophilized powder for injection (beta-1a): 22 mcg (6 million international units; Rebif), 33 mcg (6.6 million international units; Avonex), 44 mcg (12 million international units; Rebif)

Lyophilized powder for injection (beta-1b): 0.3 mg in glass, single-use, 3-ml vial

Powder for injection (beta-1b): 0.3 mg (9.6 million international units; Betaseron)

Prefilled syringes (beta-1a): 30 mcg/0.5 ml (Avonex)

Indications and dosages

➣ To reduce frequency of exacerbations in relapsing-remitting multiple sclerosis

Adults ages 18 and older: 8.8 mcg Rebif subcutaneously three times weekly, increased over a 4-week period to 44 mcg three times weekly. Or 30 mcg Avonex I.M. once a week. Or 8 million international units (0.25 mg) Betaseron subcutaneously every other day. Or initially, 0.0625 mg (0.25 ml) (Extavia) subcutaneously every other day, increased over 6 weeks to 0.25 mg (1 ml) every other day.

Contraindications

• Hypersensitivity to drug, its components, or albumin

Precautions

Use cautiously in:

• cardiac disease, seizure disorders, mental disorders, depression, suicidal tendencies

• women of childbearing age

• pregnant or breastfeeding patients

• children ages 18 and younger.

Administration

• Reconstitute Avonex (I.M. injection) and Rebif (subcutaneous injection) using diluent provided, according to instructions provided.

• Reconstitute Betaseron (subcutaneous injection) using 1.2 ml of diluent supplied by manufacturer, to yield a concentration of 0.25 mg/ml. Swirl gently to mix; don't shake. Use reconstituted drug within 3 hours; discard unused portion.

• Reconstitute Extavia (subcutaneous injection) by attaching prefilled, single-use syringe containing 1.2 ml of diluent supplied by manufacturer to vial using vial adapter. Slowly inject 1.2 ml of diluent into vial to yield a concentration of 0.25 mg/ml. Swirl gently to mix; don't shake. Use reconstituted drug within 3 hours; discard unused portion.

Adverse reactions

CNS: dizziness, confusion, rigors, paresthesia, lethargy, depression, difficulty thinking or concentrating, insomnia, anxiety, fatigue, amnesia, nervousness, drowsiness, asthenia, malaise, suicidal ideation

CV: chest pain, hypertension, palpitations, arrhythmias

EENT: visual disturbances, stye, hearing disorders, nasal congestion, sinusitis, rhinitis, pharyngitis

GI: nausea, vomiting, diarrhea, constipation, abdominal pain, dyspepsia, flatulence, eructation, stomatitis, dry mouth, intestinal obstruction

GU: gynecomastia, breast pain, early or delayed menses, menstrual bleeding or spotting, shortened duration of menstrual flow, menorrhagia

Hematologic: anemia, neutropenia, leukopenia, thrombocytopenia

Metabolic: hypocalcemia

Musculoskeletal: joint pain, back pain, myalgia, myasthenia

Respiratory: cough, dyspnea

Skin: rash, dry skin, pruritus, flushing, alopecia, dermatitis, diaphoresis

Other: gingivitis, flulike symptoms, weight loss, edema, candidiasis, lymphadenopathy, inflammation, pain

Interactions

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, blood urea nitrogen, creatinine, glucose, lactate dehydrogenase, neutralizing antibodies, phosphorus, uric acid: increased values

Hemoglobin, neutrophils, white blood cells: decreased values

Patient monitoring

See Before therapy and monthly during therapy, assess CBC with white cell differential, glucose and electrolyte levels, and liver and kidney function tests.

• Assess fluid intake and output. Keep patient well hydrated.

• Watch for GI upset. Provide small, frequent meals to minimize nausea and vomiting.

See Monitor for mental status changes, depression, and suicidal ideation.

• Evaluate for bleeding and bruising.

• Institute infection-control measures. Monitor for infection symptoms.

Patient teaching

• Teach patient or caregiver how to administer drug subcutaneously or I.M., rotate injection sites, and track dosing schedule and injection sites on calendar.

• Advise patient to avoid sources of potential infection, such as crowds and people with known infections.

• Tell patient to eat small, frequent meals to combat nausea, vomiting, and appetite loss.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration, alertness, and vision.

See Tell patient to contact prescriber immediately if depression or suicidal ideation occurs.

• Inform female patient that drug is linked to fetal abnormalities. Advise her not to get pregnant during therapy, and to use barrier contraception. Tell her to consult prescriber before breastfeeding.

See Instruct patient to immediately report signs or symptoms of infection (such as fever, chills, sore throat, achiness), unusual bleeding or bruising, mental status changes, dizziness, palpitations, or chest pain.

• Tell patient he'll need regular follow-up examinations and blood tests to monitor drug effects.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the tests mentioned above.

interferon beta-1b

(in-ter-feer-on bay-ta won-bee) interferonbeta1b,

Betaseron

(trade name),

Extavia

(trade name)

Classification

Therapeutic: anti multiple sclerosis agents
Pharmacologic: interferons
Pregnancy Category: C

Indications

Relapsing forms of multiple sclerosis (MS).MS patients who have experienced a first clinical episode and have MRI features consistent with the disease.

Action

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

Therapeutic effects

Reduce incidence of relapse (neurologic dysfunction) and slowing of physical disability.

Pharmacokinetics

Absorption: 50% absorbed following subcutaneous administration.Distribution: Unknown.Metabolism and Excretion: Unknown.Half-life: 8 min–4.3 hr.

Time/action profile (serum concentrations)

ROUTEONSETPEAKDURATION
SCrapid1–8 hrunknown

Contraindications/Precautions

Contraindicated in: Hypersensitivity to natural or recombinant interferon beta or human albumin.Use Cautiously in: Patients with a history of suicide attempt or depression; Patients with childbearing potential; Congestive HF (may worsen HF) Obstetric / Lactation / Pediatric: Safety not established.

Adverse Reactions/Side Effects

Central nervous system

  • suicidal thoughts
  • depression (most frequent)
  • headache (most frequent)
  • incoordination (most frequent)
  • insomnia (most frequent)

Respiratory

  • dyspnea

Cardiovascular

  • edema (most frequent)
  • chest pain
  • hypertension

Gastrointestinal

  • abdominal pain (most frequent)
  • constipation (most frequent)
  • nausea (most frequent)
  • vomiting (most frequent)
  • autoimmune hepatitis
  • ↑ liver enzymes

Genitourinary

  • urgency (most frequent)
  • erectile dysfunction

Dermatologic

  • rash (most frequent)

Endocrinologic

  • menstrual disorders (most frequent)
  • hyperthyroidism
  • hypothyroidism
  • menorrhagia
  • spontaneous abortion

Hematologic

  • neutropenia (most frequent)
  • anemia
  • thrombocytopenia

Local

  • injection-site reactions (most frequent)
  • injection site necrosis

Musculoskeletal

  • myalgia (most frequent)
  • muscle spasm

Miscellaneous

  • allergic reactions including anaphylaxis
  • chills (most frequent)
  • fever (most frequent)
  • flu-like symptoms (most frequent)
  • pain (most frequent)

Interactions

Drug-Drug interaction

Not known.

Route/Dosage

Subcutaneous (Adults) Initiate with 0.0625 mg every other day and then ↑ dose by 0.0625 mg every 2 wk to target dose of 0.25 mg every other day.

Availability

Powder for injection: 0.3 mg/vial

Nursing implications

Nursing assessment

  • Assess frequency of exacerbations of symptoms of multiple sclerosis periodically during therapy.
  • Monitor patient for signs of depression and suicidal tendencies during therapy. If depression occurs, notify health care professional immediately. Therapy may be discontinued.
  • Lab Test Considerations: Monitor hemoglobin, WBC, platelets, and blood chemistries including liver function tests prior to and 1, 3, and 6 mo after initiation of therapy and periodically thereafter. Therapy may be temporarily discontinued if the absolute neutrophil count is < 750/mm3, if AST or ALT exceeds 10 times the upper limit of normal, or if serum bilirubin exceeds 5 times the upper limit of normal. Once the absolute neutrophil count is > 750/mm3 or the hepatic enzymes have returned to normal, therapy can be restarted at 50% of the original dose. Thyroid function tests should also be monitored every 6 mo, especially in those patients with a history of thyroid abnormalities.

Potential Nursing Diagnoses

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

Implementation

  • Do not confuse products. Interferon beta-1a and interferon beta-1b are not interchangeable.
  • Subcutaneous: To reconstitute, inject 1.2 mL of diluent supplied into interferon beta-1b vial for a concentration of 0.25 mg/mL. Swirl gently to dissolve completely; do not shake. If foaming occurs, allow to sit undisturbed until foam dissipates. Do not use solutions that are discolored or contain particulate matter. Keep reconstituted solution refrigerated; inject within 3 hr of reconstitution.
    • Following reconstitution, withdraw 1 mL into a syringe with a 27-gauge (Extavia) or 30–gauge (Betaseron) needle, pinch skin and inject subcut at a 90° angle into arm, abdomen, hip, or thigh. Rotate sites with each injection to minimize risk of injection site reactions. Discard unused portion; vials are for single dose only.

Patient/Family Teaching

  • Home Care Issues: Instruct patient in correct technique for injection and care and disposal of equipment. 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. Patients should receive a medication guide with each product.
    • Advise patient, family and caregivers to look for suicidality. Notify health care professional immediately if thoughts about suicide or dying, attempts to commit suicide, new or worse depression or anxiety, agitation or restlessness, panic attacks, insomnia, new or worse irritability, aggressiveness, acting on dangerous impulses, mania, or other changes in mood or behavior occur.
    • Inform patients with pre-existing HF to notify health care professional if signs and symptoms of worsening HF (swollen ankles, shortness of breath, decreased ability to exercise, fast heartbeat, tightness in chest, increased need to urinate at night, not being able to lay flat in bed) immediately.
    • Inform patient that flu-like symptoms (fever, chills, myalgia, sweating, malaise) may occur during therapy. Acetaminophen may be used for relief of fever and myalgias.
    • Advise patient to notify health care professional if injection site reactions or necrosis (area is swollen and painful, looks infected, does not heal within a few days, has fluid draining from it, or breaks in your skin or blue-black skin discoloration) occur.
    • Advise patient to notify health care professional if pregnancy is planned or suspected. May cause spontaneous abortion.

Evaluation/Desired Outcomes

  • Decrease in the frequency of relapse (neurologic dysfunction) in patients with relapsing-remitting multiple sclerosis.
  • Slowed progression of disability in early-stage MS.

Betaseron®

Recombinant IFN-β1b, see there.