Comprehensive Anticoagulant Transition Table (UFH, LMWH, Fondaparinux, Warfarin, NOACs)
| Feature | UFH | LMWH | Fondaparinux | Warfarin | NOACs (Apixaban, Rivaroxaban, Dabigatran, Edoxaban) |
|---|---|---|---|---|---|
| Mechanism | Potentiates antithrombin III → inhibits thrombin & factor Xa | Potentiates antithrombin III → mainly inhibits factor Xa | Synthetic pentasaccharide → selectively inhibits factor Xa via antithrombin | Vitamin K antagonist → inhibits synthesis of factors II, VII, IX, X | Direct Xa inhibitors (apixaban, rivaroxaban, edoxaban) or direct thrombin inhibitor (dabigatran) |
| Indications | VTE treatment, ACS, bridging, HIT alternative | VTE prophylaxis & treatment, ACS | VTE prophylaxis & treatment (esp. HIT alternative), ACS off-label | VTE treatment & prevention, AF stroke prevention, mechanical valves, APS | VTE treatment & prevention, AF stroke prevention, post-orthopedic prophylaxis |
| Route | IV infusion or SC | SC | SC | Oral | Oral |
| Onset of Action | Immediate (IV) | 3–5 hrs peak | 2–3 hrs | Delayed (36–72 hrs) | Rapid (1–4 hrs) |
| Dosing (Adults) | VTE: 80 units/kg IV bolus → 18 units/kg/hr infusion | Enoxaparin: 1 mg/kg SC q12h or 1.5 mg/kg SC q24h | 5–10 mg SC daily (weight-based: <50kg: 5 mg; 50–100kg: 7.5 mg; >100kg: 10 mg) | 5 mg PO daily (adjust per INR) | Apixaban: 10 mg PO BID ×7d → 5 mg PO BID; Rivaroxaban: 15 mg PO BID ×21d → 20 mg daily; Dabigatran: 150 mg BID after 5d parenteral; Edoxaban: 60 mg daily after 5d parenteral |
| Half-life | 1–2 hrs | 4–5 hrs | 17–21 hrs | 36–72 hrs | 8–14 hrs (variable by agent) |
| Renal Adjustment | Not required | CrCl<30 ml/min: adjust or extend interval | Contraindicated if CrCl<30 ml/min | Not required directly, but monitor INR | CrCl dependent (dabigatran avoid <30 ml/min, others reduced dose) |
| Monitoring | aPTT (1.5–2.5× control) or anti-Xa | Anti-Xa if obesity, renal, pregnancy | No routine monitoring | INR (target 2–3; mechanical mitral valve 2.5–3.5) | Renal function; CBC; not routinely anti-Xa or coagulation tests |
| Transition / Bridging | Often bridge to Warfarin until INR therapeutic | Bridge to Warfarin or initial therapy for dabigatran/edoxaban VTE | Bridge to Warfarin or NOAC if needed; no direct oral switch unless overlapping for VTE | Requires overlap ≥5 days with parenteral anticoagulant (UFH/LMWH/Fondaparinux) | Minimal bridging; dabigatran/edoxaban require 5 days parenteral for VTE |
| Reversal Agent | Protamine sulfate | Protamine partial (≤60% reversal) | No specific antidote; PCC may be considered | Vitamin K ± PCC or FFP | Idarucizumab (dabigatran), Andexanet alfa (Xa inhibitors), PCC (off-label) |
| Special Considerations / Pharmacist Pearls | Preferred in renal failure, unstable patients; rapid titration | Outpatient bridging, predictable PK, lower HIT risk | Only SC; contraindicated in severe renal impairment; caution in elderly <50 kg | Narrow therapeutic index, multiple drug & food interactions; patient education critical | Rapid onset/offset; fewer interactions; monitor renal function; some require parenteral start for VTE |
| Pregnancy | Safe (does not cross placenta) | Safe | Limited data; generally avoided; consult hematology | CI (teratogenic) | CI (except selected cases under hematology guidance) |
Key Clinical Notes for Fondaparinux
- Renal caution: contraindicated if CrCl <30 mL/min.
- HIT alternative: safe in patients with history of heparin-induced thrombocytopenia.
- Bridging: used as parenteral bridge to Warfarin; can also be initial therapy for VTE before transitioning to NOACs.
- Monitoring: routine anti-Xa levels not required in most adults; monitor renal function.
- Reversal: no specific antidote; in life-threatening bleeding, supportive care + PCC can be considered.
NOACs (DOACs) Comparison Table – Clinical Pharmacist Focus
| Feature | Dabigatran | Rivaroxaban | Apixaban | Edoxaban |
|---|---|---|---|---|
| Class / Mechanism | Direct thrombin inhibitor (factor IIa) | Direct factor Xa inhibitor | Direct factor Xa inhibitor | Direct factor Xa inhibitor |
| Indications | NVAF stroke prevention, VTE treatment & prevention | NVAF stroke prevention, VTE treatment & prevention, post-orthopedic prophylaxis | NVAF stroke prevention, VTE treatment & prevention, post-orthopedic prophylaxis | NVAF stroke prevention, VTE treatment & prevention |
| Route | Oral | Oral | Oral | Oral |
| Onset of Action | 1–2 hrs | 2–4 hrs | 3–4 hrs | 1–2 hrs |
| Half-life | 12–17 hrs | 5–9 hrs (young), 11–13 hrs (elderly) | 12 hrs | 10–14 hrs |
| Dosing – NVAF | 150 mg BID (CrCl >30 mL/min) | 20 mg daily with evening meal (CrCl >50 mL/min) | 5 mg BID (reduce to 2.5 mg BID if ≥2 risk factors: age ≥80, weight ≤60 kg, Scr ≥1.5 mg/dL) | 60 mg daily (CrCl >50 mL/min) |
| Dosing – VTE Treatment | After 5 days LMWH: 150 mg BID | 15 mg BID ×21d → 20 mg daily | 10 mg BID ×7d → 5 mg BID | 60 mg daily after 5 days LMWH |
| Renal Adjustment | CrCl 30–50 mL/min: 150 mg BID; avoid <30 mL/min | CrCl 15–50 mL/min: 15 mg daily; avoid <15 mL/min | CrCl 15–30 mL/min: 2.5 mg BID; avoid <15 mL/min | CrCl 15–50 mL/min: 30 mg daily; avoid <15 mL/min |
| Hepatic Considerations | Avoid severe hepatic impairment | Avoid severe hepatic impairment | Avoid severe hepatic impairment | Avoid severe hepatic impairment |
| Monitoring | Renal function, CBC | Renal function, CBC | Renal function, CBC | Renal function, CBC |
| Reversal Agent | Idarucizumab | Andexanet alfa | Andexanet alfa | Andexanet alfa |
| Drug Interactions | P-gp substrate: avoid with strong P-gp inhibitors (e.g., dronedarone, ketoconazole) | CYP3A4 + P-gp substrate; avoid strong dual inhibitors (ketoconazole, ritonavir) | CYP3A4 + P-gp substrate; avoid strong dual inhibitors | CYP3A4 + P-gp substrate; avoid strong dual inhibitors |
| Bleeding Risk / Pearls | Highest GI bleeding risk among NOACs; nonvalvular AF only | Take with food if ≥15 mg dose; caution GI risk | Lowest risk of major bleeding in elderly; dose adjustment critical in frail/elderly | Slightly lower efficacy if CrCl >95 mL/min for NVAF; monitor renal function |
| Bridging | Requires 5 days parenteral anticoagulation for VTE treatment start | Oral start; no parenteral bridging required | Oral start; no parenteral bridging required | Requires 5 days parenteral anticoagulation for VTE treatment start |
Clinical Pharmacist Notes
- Renal function monitoring is essential before initiation and periodically thereafter.
- Drug-drug interactions: strong CYP3A4/P-gp inhibitors and inducers significantly affect Xa inhibitors; dabigatran mainly affected by P-gp.
- Bridging: only dabigatran and edoxaban require parenteral anticoagulation at VTE initiation.
- Reversal: idarucizumab is specific for dabigatran; andexanet alfa for Xa inhibitors.
- Dose adjustments are critical for elderly, low body weight, renal impairment, or concomitant medications.
- Patient counseling: adherence is crucial due to short half-life; educate on missed dose action.