Apixaban
Eliquis
Direct oral anticoagulant — factor Xa inhibitor
Direct factor Xa inhibitor. Lowest bleeding risk among DOACs in many comparisons; least renal dependence (~27% renal).
Indications
- •AF stroke prevention
- •VTE treatment + prevention
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| AF | 5 mg PO BID (2.5 mg BID if ≥2 of: age ≥80, weight ≤60 kg, Cr ≥1.5) | — |
| VTE treatment | 10 mg PO BID × 7 days, then 5 mg BID | — |
Pharmacokinetics
Onset 3–4 h. Half-life ~12 h. ~27% renal clearance (usable in mild-moderate renal impairment). No food effect.
Side effects
- !Bleeding (lower than other DOACs in ARISTOTLE)
- !No routine monitoring
Contraindications
- ×Severe hepatic disease
- ×Mechanical valves
- ×Active bleeding
Reversal / antidote
Andexanet alfa (Andexxa) — specific; 4-factor PCC alternative
Clinical pearls
- ★ASRA neuraxial: hold 72 h before neuraxial block/catheter removal; restart 6 h after.
- ★Least renally dependent DOAC — often preferred in CKD.
- ★Twice-daily dosing — adherence matters more than once-daily agents.
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).
Suggested reading
- •Miller's Anesthesia, 9e
- •FDA package insert
- •ASRA regional anesthesia in the anticoagulated patient guidelines, 2018
