interferon [IFN]-beta 1A (Avonex)
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Introduction
Tradename: Avonex. Recombinant protein.
Indications
relapsing forms of multiple sclerosis
Contraindications
- hypersensitivity to albumin
- hypersensitivity to E. coli-derived products
- not recommended in patients with liver disease[6]
Caution:
- history of depression
- history of seizures
- history of cardiac disease
Dosage
6 million units (30 ug) SC/IM weekly
Powder for injection: (lyophilized) 33 ug (6.6 million units)
Pharmacokinetics
- filtered by renal tubules
- proteolytic degradation during renal tubular reabsorption
Monitor
- complete blood count (CBC)[6]
- liver function tests every 6 months[5]
- in Canada, baseline, monthly for 1st 6 months, then every 6 months[5]
- serum chemistries
Adverse effects
- common (> 10%)
- less common (1-10%)
- tachycardia, syncope, headache, lethargy, depression, emotional lability, anxiety, suicidal ideation, somnolence, agitation, confusion, hypocalcemia, spasticity, nausea/vomiting, anorexia, diarrhea, chronic weight loss, leukopenia, thrombocytopenia, anemia (mild, dose-related), retinal toxicity, visual changes, renal insufficiency (elevated BUN & serum creatinine) elevated liver function tests (mild & transient)
- uncommon (< 1%)
Drug interactions
- decreased clearance/increased toxicity of zidovudine
Laboratory
Mechanism of action
- reduces frequency of relapse & new brain lesions visualized by MRI
- slows progression of physical disability
- neutralizing antibodies IFN-beta are produced diminishing clinical effectiveness[5]
More general terms
- biological response modifier
- neurologic agent
- recombinant protein; chimer
- interferon beta
- pharmaceutical interferon
References
- ↑ The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- ↑ Kaiser Permanente Northern California Regional Drug Formulary, 1998
- ↑ 3.0 3.1 U.S. Food and Drug Administration (FDA) http://www.fda.gov/medwatch/SAFETY/2005/safety05.htm#Avonex
- ↑ Department of Veterans Affairs, VA National Formulary
requires cosign by neurology chief - ↑ 5.0 5.1 5.2 5.3 Prescriber's Letter 17(7): 2010 Recommended Lab Monitoring for Common Medications Liver Function Test Scheduling Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=260704&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ 6.0 6.1 6.2 6.3 Medical Knowledge Self Assessment Program (MKSAP) 17, 18. American College of Physicians, Philadelphia 2015, 2018