Dalteparin
Fragmin
Low-molecular-weight heparin (LMWH)
Antithrombin-mediated factor Xa > IIa inhibition. Similar profile to enoxaparin; preferred LMWH in cancer-associated VTE (CLOT trial).
Indications
- •VTE prophylaxis + treatment
- •Cancer-associated thrombosis
- •ACS
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| VTE prophylaxis | 5000 units SC daily | — |
| Treatment | 200 units/kg SC daily (or 100 units/kg q12h) | — |
| Cancer VTE | 200 units/kg daily × 1 mo, then 150 units/kg daily | — |
Pharmacokinetics
Onset 3–4 h SC. Half-life ~3–5 h. Renally cleared; less accumulation than enoxaparin in mild renal impairment.
Side effects
- !Bleeding
- !HIT (uncommon)
- !Injection-site reaction
Contraindications
- ×Active bleeding
- ×HIT history (relative)
Reversal / antidote
Protamine partial reversal (as for enoxaparin)
Clinical pearls
- ★ASRA neuraxial: same LMWH rules — hold 12 h prophylactic / 24 h therapeutic.
- ★First-line LMWH for cancer-associated VTE historically; DOACs now competitive.
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.
- Tinzaparin
Antithrombin-mediated factor Xa > IIa inhibition; higher mean molecular weight than enoxaparin (anti-Xa:IIa ~1.9:1).
Suggested reading
- •Miller's Anesthesia, 9e
- •FDA package insert
- •ASRA regional anesthesia in the anticoagulated patient guidelines, 2018
