Dabigatran
Pradaxa
Direct oral anticoagulant — direct thrombin (IIa) inhibitor
Directly and reversibly inhibits thrombin (factor IIa), both free and clot-bound. Prodrug (dabigatran etexilate).
Indications
- •AF stroke prevention
- •VTE treatment + prevention
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| AF | 150 mg PO BID (75 mg BID if CrCl 15–30) | — |
| VTE | 150 mg PO BID after 5–10 days parenteral anticoagulation | — |
Pharmacokinetics
Onset 1–2 h. Half-life 12–17 h (longer with renal impairment). ~80% RENALLY cleared — most renally dependent DOAC.
Side effects
- !Bleeding (GI dyspepsia common — tartaric acid core)
- !Accumulation in renal failure
Contraindications
- ×CrCl <15 (or <30 per some labels)
- ×Mechanical valves
- ×Active bleeding
Reversal / antidote
Idarucizumab (Praxbind) — specific, rapid, complete; hemodialysis also removes it
Clinical pearls
- ★ASRA neuraxial: hold 72 h (normal renal function); up to 96–120 h if CrCl reduced.
- ★Has a specific, complete antidote — idarucizumab (Praxbind) 5 g IV.
- ★Most renally cleared DOAC + dialyzable — both matter in bleeding/renal patients.
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
- •ASRA regional anesthesia in the anticoagulated patient guidelines, 2018
