Peginterferon Beta-1a
Peginterferon Beta-1a is a pegylated interferon therapy used to treat relapsing forms of multiple sclerosis. It works as an immunomodulator to reduce inflammation and slow disease progression.
A long-acting interferon injection for relapsing MS that reduces relapse frequency and delays disability progression.
Key facts at a glance
- ATC
- L03AB13
- RxNorm
- 1546168
- Generic
- Peginterferon Beta-1a
- Class
- atc-l03
- Brands
- Plegridy
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- prefilled syringe
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 125 mcg
- Maximum
- consult physician
- Frequency
- every 2 weeks
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 125 mcg
- Maximum
- consult physician
- Frequency
- every 2 weeks
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 125 mcg
- Maximum
- consult physician
- Frequency
- every 2 weeks
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
9 groupspregnancy
first trimesteravoid if possible
discontinue therapy prior to conception if possible; avoid use during pregnancy unless benefits to mother clearly outweigh potential risks to fetus
regular fetal ultrasound monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
second and third trimesteravoid if possible
do not initiate during pregnancy; discontinue upon pregnancy confirmation unless absolutely necessary
regular fetal growth monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
lactation
not recommendeddiscontinue breastfeeding
do not breastfeed during peginterferon beta-1a therapy; interferon beta-1a may be excreted in human milk and could harm infant
n/a
Use of this medication in this population requires careful consideration of risks and benefits.
pediatric_age
adolescents 12 to 17 yearsuse with caution
safety and efficacy not established in pediatric patients; use only if benefits outweigh potential risks
close monitoring of growth and development, liver function tests
geriatric
elderly 65 years and olderno specific dose adjustment required but monitor closely
use with caution; geriatric patients may have increased sensitivity to adverse effects including flu-like symptoms, depression, and liver toxicity
regular monitoring of liver function, complete blood count, thyroid function
Use with caution and monitor for adverse effects.
renal_impairment
mild to moderateno initial dose adjustment; monitor renal function
use with caution in patients with mild to moderate renal impairment; monitor serum creatinine and renal function tests regularly
baseline and periodic renal function assessment
Use with caution and monitor for adverse effects.
renal_impairment
severeconsider dose reduction or extended dosing interval
use with caution in severe renal impairment; consider dose adjustment and increased monitoring intervals
frequent renal function monitoring, consider pharmacokinetic evaluation
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderateno initial dose adjustment but monitor closely
use with caution; interferon beta products can cause hepatotoxicity; monitor liver enzymes closely
baseline liver function tests and regular monitoring every 3-6 months
Use with caution and monitor for adverse effects.
hepatic_impairment
severeavoid use
not recommended in severe hepatic impairment due to increased risk of hepatotoxicity and liver failure
n/a - avoid use
Use of this medication in this population requires careful consideration of risks and benefits.
Statistics and clinical data
FDA approval year
Peginterferon Beta-1a (Plegridy) FDA approval date
Drug class
Classification as immunomodulatory therapy
Common uses
Therapeutic indication for MS treatment
Administration frequency
Subcutaneous injection dosing schedule
Peginterferon Beta-1a is indicated for the treatment of relapsing forms of multiple sclerosis (MS), including clinically isolated syndrome, relapsing-remitting MS, and active secondary progressive disease.
As a pegylated form of interferon beta-1a, it modulates immune responses and reduces inflammation. The exact mechanism by which it exerts its effects in MS patients is unknown.
Administered by subcutaneous injection every 2 weeks. Common side effects include flu-like symptoms, injection site reactions, and elevated liver enzymes. Regular monitoring may be required during treatment. Contraindicated in pregnancy and in patients with known hypersensitivity to the product.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy