General

Pronunciation:
in-ter-feer-on bay-ta won-bee

Trade Name(s)

• Betaseron

Ther. Class.

anti-multiple sclerosis agents

immune modifiers

Pharm. Class.

interferons

Indications

Relapsing forms of multiple sclerosis (MS), including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive 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 Effect(s):

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

Pharmacokinetics

Absorption: 50% absorbed following SUBQ administration.

Distribution: Unknown.

Metabolism and Excretion: Unknown.

Half-life: 8 min–4.3 hr.

TIME/ACTION PROFILE (plasma concentrations)

Contraindication/Precautions

Contraindicated in:

• Hypersensitivity to natural or recombinant interferon beta or human albumin.

Use Cautiously in:

• History of suicide attempt or depression;
• HF (may worsen HF);
• Latex sensitivity;
• OB:   Safety not established in pregnancy;
• Lactation:  Use while breastfeeding only if potential maternal benefit justifies potential risk to infant;
• Pedi:   Safety and effectiveness not established in children.

Adverse Reactions/Side Effects

CV: edema, chest pain, hypertension

Derm: rash

Endo: menstrual disorders, hyperthyroidism, hypothyroidism, menorrhagia

GI: abdominal pain, constipation, nausea, vomiting, autoimmune hepatitis, ↑ liver enzymes

GU: urgency, erectile dysfunction, spontaneous abortion

Hemat: neutropenia, anemia, HEMOLYTIC UREMIC SYNDROME, thrombocytopenia, THROMBOTIC THROMBOCYTOPENIC PURPURA

Local: injection-site reactions , injection site necrosis

MS: myalgia, pain, muscle spasm

Neuro: depression, headache, incoordination, insomnia, SUICIDAL THOUGHTS

Resp: dyspnea, PULMONARY ARTERIAL HYPERTENSION

Misc: chills, fever, flu-like symptoms, drug-induced lupus erythematosus, HYPERSENSITIVITY REACTIONS(including anaphylaxis)

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

Interactions

Drug-Drug

None reported.

Route/Dosage

SUBQ (Adults): 0.0625 mg every other day, 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

Assessment

• Assess frequency of exacerbations of symptoms of multiple sclerosis periodically during therapy.
• Monitor for injection site abscesses, cellulitis, and injection site necrosis; may require hospitalization for surgical drainage and intravenous antibiotics.
• Monitor for dyspnea or new/increased fatigue. If these symptoms develop, assess patient for pulmonary arterial hypertension.
• 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 (ULN), or if serum bilirubin exceeds 5 times the ULN. 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.

Implementation

• Do not confuse products. Interferon beta-1a and interferon beta-1b are not interchangeable.
  • Premedicate with antipyretics and/or analgesics to prevent flu-like symptoms.
• SUBQ 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. Rubber cap of diluent prefilled syringe of Extavia contains latex and should not be handled by individuals allergic to latex.
  • Following reconstitution, withdraw 1 mL into a syringe with a 27-gauge (Extavia) or 30-gauge (Betaseron) needle, pinch skin and inject SUBQ 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 in 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. Take missed doses as soon as remembered. Take next injection 48 hr after injection; do not take medication on 2 consecutive days. Advise patient to read  Medication Guide  before starting therapy and with each Rx refill in case of changes.
• 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.
• May cause injection site reactions, including injection site necrosis. Periodically assess patient understanding and use of aseptic self-injection techniques, particularly if injection site necrosis has occurred. Discontinuation of therapy following a single site of necrosis is based on the extent of necrosis. For patients who continue therapy after injection site necrosis has occurred, avoid administration into affected area until fully healed. If multiple lesions occur, change injection site or discontinue therapy until healing occurs.
• Advise patient to notify health care professional if shortness of breath, difficulty breathing, fatigue injection site reactions, rash, 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), or signs and symptoms of liver problems (yellowing of eyes, itchy skin, nausea or vomiting, feeling very tired, flu-like symptoms, bruising easily, or bleeding problems) occur.
• Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care professional before taking any new medications.
• Rep:  Advise females of reproductive potential 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.
• Slowed progression of disability in early-stage MS.