PRAXBIND

Clinical safety rating: caution

Comprehensive clinical and safety monograph for PRAXBIND (PRAXBIND).

How it works

Idarucizumab is a humanized monoclonal antibody fragment (Fab) that binds specifically to dabigatran and its acylglucuronide metabolites with high affinity (approximately 350-fold higher than the affinity of dabigatran for thrombin), neutralizing their anticoagulant effect in a concentration-dependent manner.

What the body does with it

Metabolism	Idarucizumab is a monoclonal antibody fragment, not metabolized by cytochrome P450 enzymes; it is degraded via catabolic pathways to small peptides and amino acids.
Excretion	Primarily renal: ~80% of the dose is excreted unchanged in urine within 6-12 hours. A small fraction (approximately 1-2%) undergoes hepatic metabolism via amidase cleavage to form a carboxylic acid metabolite (M2), which is excreted renally. Fecal excretion accounts for <5%.
Half-life	Terminal elimination half-life is approximately 1.1 hours (range 0.9-1.4 hours) in healthy subjects. This short half-life allows rapid reversal of anticoagulant effect; however, sustained reversal requires continuous intravenous infusion due to idarucizumab's own elimination.
Protein binding	Idarucizumab exhibits negligible protein binding (<1%) as it is a humanized monoclonal antibody fragment.
Volume of Distribution	Volume of distribution is approximately 0.8 L/kg (range 0.4-1.2 L/kg), indicating distribution primarily within the extracellular fluid space, consistent with a large protein molecule.
Bioavailability	Not applicable for intravenous administration; bioavailability is 100% when given IV.
Onset of Action	Intravenous bolus: Reversal of anticoagulant effect begins within minutes; 100% reversal of dabigatran anticoagulant activity is achieved within 5 minutes as measured by diluted thrombin time or ecarin clotting time.
Duration of Action	After a single 5 g IV dose, reversal of dabigatran-induced anticoagulation is sustained for up to 24 hours based on clotting assays. However, clinical duration may be shorter if dabigatran has a prolonged half-life (e.g., renal impairment), and reversal may diminish as idarucizumab is cleared. Re-dosing may be required if dabigatran levels rebound.

Classification & Brands

Dosing & administration

5 g intravenous bolus, followed by a second 5 g dose if needed (max 10 g total). Administer as two consecutive 50 mL infusions over 5-10 minutes each.

Dosage form	INJECTABLE
Renal impairment	No dose adjustment required for renal impairment. Idarucizumab is not removed by dialysis.
Liver impairment	No dose adjustment required for hepatic impairment.
Pediatric use	Safety and efficacy not established in pediatric patients. No approved dosing guidelines.
Geriatric use	No specific dose adjustment required. Use standard dosing based on clinical response and bleeding severity.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for PRAXBIND (PRAXBIND).

Breastfeeding	Unknown if excreted in human milk; likely minimal due to large molecular weight and short half-life. M/P ratio not established. Caution advised.
Teratogenic Risk	PRAXBIND (idarucizumab) is a monoclonal antibody fragment. No adequate human studies; animal studies not reproductive. Theoretical risk of fetal harm is low due to IgG class crossing placenta only after first trimester, but no direct teratogenic effects known. Use only if clearly needed.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Common Effects	Diarrhea Stomach pain
Serious Effects

Absolute Contraindications

["None known."]

Clinical Precautions

Precautions

["Thromboembolic risk: Reversal of anticoagulant effects may expose patients to the thrombotic risk of their underlying disease. Reinitiate anticoagulation as soon as medically appropriate.","Hypersensitivity reactions: Allergic reactions (including anaphylaxis) have been reported.","Re-elevation of dabigatran levels: In patients with severe renal impairment (CrCl ≤30 mL/min) or those who received a second dose of dabigatran within 12 hours after idarucizumab, dabigatran levels may re-elevate. Monitor for rebleeding and consider repeat dosing.","Not for use in patients not on dabigatran therapy."]

Clinical Tips & Counseling

Drug interactions

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PRAXBIND

Clinical safety rating: caution

Comprehensive clinical and safety monograph for PRAXBIND (PRAXBIND).

How it works

What the body does with it

Metabolism	Idarucizumab is a monoclonal antibody fragment, not metabolized by cytochrome P450 enzymes; it is degraded via catabolic pathways to small peptides and amino acids.
Excretion	Primarily renal: ~80% of the dose is excreted unchanged in urine within 6-12 hours. A small fraction (approximately 1-2%) undergoes hepatic metabolism via amidase cleavage to form a carboxylic acid metabolite (M2), which is excreted renally. Fecal excretion accounts for <5%.
Half-life	Terminal elimination half-life is approximately 1.1 hours (range 0.9-1.4 hours) in healthy subjects. This short half-life allows rapid reversal of anticoagulant effect; however, sustained reversal requires continuous intravenous infusion due to idarucizumab's own elimination.
Protein binding	Idarucizumab exhibits negligible protein binding (<1%) as it is a humanized monoclonal antibody fragment.
Volume of Distribution	Volume of distribution is approximately 0.8 L/kg (range 0.4-1.2 L/kg), indicating distribution primarily within the extracellular fluid space, consistent with a large protein molecule.
Bioavailability	Not applicable for intravenous administration; bioavailability is 100% when given IV.
Onset of Action	Intravenous bolus: Reversal of anticoagulant effect begins within minutes; 100% reversal of dabigatran anticoagulant activity is achieved within 5 minutes as measured by diluted thrombin time or ecarin clotting time.
Duration of Action	After a single 5 g IV dose, reversal of dabigatran-induced anticoagulation is sustained for up to 24 hours based on clotting assays. However, clinical duration may be shorter if dabigatran has a prolonged half-life (e.g., renal impairment), and reversal may diminish as idarucizumab is cleared. Re-dosing may be required if dabigatran levels rebound.

Classification & Brands

Dosing & administration

5 g intravenous bolus, followed by a second 5 g dose if needed (max 10 g total). Administer as two consecutive 50 mL infusions over 5-10 minutes each.

Dosage form	INJECTABLE
Renal impairment	No dose adjustment required for renal impairment. Idarucizumab is not removed by dialysis.
Liver impairment	No dose adjustment required for hepatic impairment.
Pediatric use	Safety and efficacy not established in pediatric patients. No approved dosing guidelines.
Geriatric use	No specific dose adjustment required. Use standard dosing based on clinical response and bleeding severity.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for PRAXBIND (PRAXBIND).

Breastfeeding	Unknown if excreted in human milk; likely minimal due to large molecular weight and short half-life. M/P ratio not established. Caution advised.
Teratogenic Risk	PRAXBIND (idarucizumab) is a monoclonal antibody fragment. No adequate human studies; animal studies not reproductive. Theoretical risk of fetal harm is low due to IgG class crossing placenta only after first trimester, but no direct teratogenic effects known. Use only if clearly needed.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Common Effects	Diarrhea Stomach pain
Serious Effects

Absolute Contraindications

["None known."]

Clinical Precautions

Precautions

Clinical Tips & Counseling

Drug interactions

Loading safety data…