Fitusiran
Fitusiran is an RNAi therapeutic designed to treat hemophilia by reducing antithrombin, a natural anticoagulant protein. By lowering antithrombin levels, it aims to rebalance the coagulation cascade and reduce bleeding episodes in patients with hemophilia A or B.
Fitusiran is an siRNA therapy that reduces antithrombin production to help prevent bleeding in hemophilia patients.
This medication carries a boxed (black box) warning — the strongest type of FDA warning. Review the full prescribing information before use.
Key facts at a glance
- ATC
- B02BX12
- RxNorm
- 2709439
- Generic
- Fitusiran
- Class
- atc-b02
- Brands
- Qfitlia
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- injection
- 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
- 500mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 250mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 400mg daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
10 groupspregnancy
first trimesteravoid if possible
avoid use during pregnancy unless benefits outweigh risks; insufficient data available
regular fetal monitoring recommended
pregnancy
second third trimesteravoid if possible
continue only if already receiving therapy and benefits outweigh risks
regular fetal monitoring and growth assessments
lactation
not applicableno adjustment
discontinue breastfeeding or avoid use; excretion in breast milk unknown
monitor infant for adverse effects
pediatric_age
adolescents 12 to 17 yearsno adjustment
approved for use in patients 12 years and older with hemophilia A or B
regular monitoring of antithrombin levels and liver function
pediatric_age
children under 12use with caution
not recommended in children under 12 years due to limited safety and efficacy data
close monitoring required if used off-label
geriatric
65 years and olderindividualize dosing
use with caution; consider renal and hepatic function; limited data in elderly
monitor renal function, hepatic function, and antithrombin levels regularly
Use with caution and monitor for adverse effects.
renal_impairment
mild moderateno specific adjustment recommended
use with caution; monitor renal function and antithrombin levels
regular monitoring of renal function and drug levels
Use with caution and monitor for adverse effects.
renal_impairment
severeuse with caution
use with caution; limited clinical data available
close monitoring of renal function and antithrombin levels recommended
Use with caution and monitor for adverse effects.
hepatic_impairment
mildno specific adjustment recommended
use with caution; limited data available
monitor liver function tests
Use with caution and monitor for adverse effects.
hepatic_impairment
moderate severeavoid
not recommended in patients with moderate to severe hepatic impairment
regular hepatic function monitoring if used
Use of this medication in this population requires careful consideration of risks and benefits.
Statistics and clinical data
Drug class
Fitusiran is a small interfering RNA (siRNA) therapeutic
Mechanism of action
Targets liver-expressed serpin family C member 1 mRNA
Therapeutic indication
Treatment of hemophilia in adults and adolescents
Route of administration
Subcutaneous administration with dosing every 3 months
Fitusiran is indicated for the treatment of hemophilia A and B to prevent or reduce the frequency of bleeding episodes.
Fitusiran is a double-stranded siRNA that selectively degrades antithrombin messenger RNA (mRNA) through RNA interference, thereby reducing plasma antithrombin levels and promoting a pro-coagulant state.
As a subcutaneous injection, Fitusiran requires monitoring for liver function and antithrombin levels. Patients should be aware of potential thrombotic risks and the need for regular follow-up with their healthcare provider.
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