Idarucizumab
Praxbind
Monoclonal antibody fragment — dabigatran reversal agent
Humanized Fab that binds dabigatran with ~350× the affinity of thrombin → immediate, complete neutralization.
Indications
- •Dabigatran reversal for life-threatening bleeding or emergent surgery
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| Reversal | 5 g IV (two 2.5 g vials), given as bolus or two consecutive infusions | — |
Pharmacokinetics
Onset within minutes — normalizes dilute thrombin time immediately (RE-VERSE AD).
Side effects
- !Thrombotic risk once dabigatran removed (restart anticoagulation when safe)
- !Rare hypersensitivity
Contraindications
- ×None absolute
Clinical pearls
- ★SPECIFIC to dabigatran only — no effect on factor Xa inhibitors.
- ★Re-dosing occasionally needed if dabigatran redistributes (high levels/renal failure).
- ★Resume anticoagulation as soon as clinically appropriate — reversal leaves prothrombotic state.
Other drugs in Coagulation Related
- Heparin (unfractionated)
Activates antithrombin → inactivates IIa (thrombin) and Xa.
- Tranexamic Acid (TXA)
Reversibly binds plasminogen, blocking conversion to plasmin → preserves fibrin clot.
- Protamine Sulfate
Strongly basic (positive-charge) protein binds to highly acidic (negative-charge) heparin → inactive ionic complex → renal excretion. 1 mg protamine neutralizes ~100 units heparin.
- DDAVP (Desmopressin)
Selective V2 agonist (renal water retention + Factor VIII/vWF release from endothelial Weibel-Palade bodies). NO V1 vasopressor activity at therapeutic dose.
- Warfarin
Inhibits vitamin K epoxide reductase (VKORC1) → depletes reduced vitamin K → ↓ synthesis of factors II, VII, IX, X and proteins C/S. Full effect takes days (waits for existing factor decay).
- Enoxaparin
Antithrombin-mediated inhibition, weighted toward factor Xa over IIa (~3.8:1). More predictable than UFH — no routine monitoring.
- Dalteparin
Antithrombin-mediated factor Xa > IIa inhibition. Similar profile to enoxaparin; preferred LMWH in cancer-associated VTE (CLOT trial).
- Tinzaparin
Antithrombin-mediated factor Xa > IIa inhibition; higher mean molecular weight than enoxaparin (anti-Xa:IIa ~1.9:1).
Browse all classes: /reference/drugs
Suggested reading
- •Miller's Anesthesia, 9e
- •FDA package insert
