Drug Guide
Interferon Beta-1b
Classification
Therapeutic: Immunomodulator, used in Multiple Sclerosis
Pharmacological: Interferon, cytokine
FDA Approved Indications
- Relapsing forms of multiple sclerosis (MS)
Mechanism of Action
Modulates the immune system by inhibiting the proliferation of activated T-cells, reducing inflammatory cytokines, and limiting blood-brain barrier permeability, thereby decreasing MS relapses.
Dosage and Administration
Adult: Initial dose is 250 mcg subcutaneously every other day. Dose may be increased gradually based on response and tolerability.
Pediatric: Not approved for pediatric use.
Geriatric: Use with caution, as response may be variable and side effects more prominent.
Renal Impairment: No specific dosage adjustment; monitor kidney function.
Hepatic Impairment: Use with caution; no specific dosage guidelines.
Pharmacokinetics
Absorption: Subcutaneously absorbed with peak levels in 3-10 hours.
Distribution: Distributed mainly in plasma and extracellular fluid.
Metabolism: Metabolized by proteolytic enzymes.
Excretion: Excreted mainly in the urine after degradation; no significant renal clearance.
Half Life: Approximately 8 hours.
Contraindications
- Hypersensitivity to interferons or any component of the formulation.
Precautions
- Monitor for development of neutralizing antibodies, flu-like symptoms, liver function abnormalities, depression, and injection site reactions. Use with caution in patients with depression or suicidal ideation.
- Pregnancy Category C; use only if clearly needed.
Adverse Reactions - Common
- Injection site reactions (redness, swelling, pain) (Very common)
- Flu-like symptoms (fever, chills, malaise) (Common)
Adverse Reactions - Serious
- Hepatotoxicity (elevated liver enzymes, hepatitis) (Uncommon)
- Neuropsychiatric effects (depression, suicidal ideation) (Rare)
- Myelosuppression (neutropenia, thrombocytopenia) (Uncommon)
- Autoimmune disorders (thyroiditis) (Rare)
Drug-Drug Interactions
- Live vaccines (contraindicated)
- Other immunomodulators
Drug-Food Interactions
- None significant
Drug-Herb Interactions
- None established
Nursing Implications
Assessment: Baseline and periodic liver function tests, CBC, thyroid function, neuropsychiatric assessment.
Diagnoses:
- Risk for infection
- Imbalanced nutrition: less than body requirements due to flu-like symptoms
- Risk for mood disturbance
Implementation: Administer subcutaneously as prescribed; educate patient on injection technique and side effects; monitor for adverse reactions.
Evaluation: Assess reduction in relapse rate, monitor for adverse effects, ensure laboratory parameters remain within normal limits.
Patient/Family Teaching
- Instruct on proper injection site rotation and technique.
- Report severe side effects like depression or liver issues.
- Explain the importance of regular blood tests.
- Discuss flu-like symptoms and measures to alleviate them.
- Emphasize adherence to therapy.
Special Considerations
Black Box Warnings:
- Suicide warning: Use with caution due to possible neuropsychiatric effects.
Genetic Factors: Presence of neutralizing antibodies can reduce efficacy.
Lab Test Interference: May cause transient abnormal liver function tests and hematological changes.
Overdose Management
Signs/Symptoms: Severe flu-like symptoms, injection site reactions, or symptoms of hypersensitivity.
Treatment: Supportive care; no specific antidote.
Storage and Handling
Storage: Refrigerate at 2°C to 8°C (36°F to 46°F). Do not freeze.
Stability: Stable until the expiration date when stored properly.