Chart — Pharmacology
Anticoagulants Chart
Anticoagulants prevent clot formation or extension and are among the most commonly used and highest-risk medications in clinical practice. This chart compares mechanism, monitoring, therapeutic targets, and reversal for the major anticoagulant classes.
Educational use only. Anticoagulant dosing, monitoring parameters, and reversal protocols vary by indication, patient weight, renal function, and institutional protocol. Always follow provider orders and current clinical guidelines. Data sourced from ACCP/ISTH guidelines. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
Anticoagulant Comparison
| Drug | Mechanism | Route | Monitoring | Reversal Agent |
|---|---|---|---|---|
| Heparins | ||||
| Unfractionated Heparin (UFH) | Activates antithrombin III → inhibits thrombin (IIa) and Factor Xa | IV infusion, SQ | aPTT (goal: 60–100 s); anti-Xa; platelet count (HIT risk) | Protamine sulfate |
| LMWH — Enoxaparin | Primarily inhibits Factor Xa via antithrombin III | SQ | Anti-Xa level (if indicated: renal failure, obesity, pregnancy) | Protamine sulfate (partial) |
| Fondaparinux | Selective Factor Xa inhibitor via antithrombin III | SQ | Anti-Xa level; renal function | No specific reversal agent |
| Vitamin K Antagonists | ||||
| Warfarin (Coumadin) | Inhibits Vitamin K-dependent clotting factors (II, VII, IX, X) | PO | INR (goal: 2.0–3.0 standard; 2.5–3.5 mechanical valves) | Vitamin K (slow), FFP / PCC (urgent) |
| Direct Oral Anticoagulants (DOACs) | ||||
| Dabigatran (Pradaxa) | Direct thrombin (Factor IIa) inhibitor | PO | Renal function (renally cleared); no routine INR/aPTT | Idarucizumab (Praxbind) |
| Rivaroxaban (Xarelto) | Direct Factor Xa inhibitor | PO (with food for > 10 mg doses) | Renal function; no routine lab monitoring | Andexanet alfa (Andexxa) |
| Apixaban (Eliquis) | Direct Factor Xa inhibitor | PO | Renal function; no routine lab monitoring | Andexanet alfa (Andexxa) |
| Direct Thrombin Inhibitors (IV) | ||||
| Argatroban | Direct thrombin inhibitor; used in HIT | IV infusion | aPTT (goal: 1.5–3× baseline); liver function | No specific reversal agent |
Heparin-Induced Thrombocytopenia (HIT)
HIT is a life-threatening immune-mediated complication of heparin therapy. It is paradoxically associated with thrombosis — not just bleeding — despite causing low platelet counts.
- Suspect HIT when platelets drop > 50% from baseline, typically 5–10 days after heparin initiation (or within 24 hours if prior heparin exposure)
- All forms of heparin must be immediately discontinued — including heparin flushes and heparin-coated catheters
- Switch to a non-heparin anticoagulant (argatroban or fondaparinux)
- 4Ts scoring tool is commonly used to assess HIT probability
Nursing Safety Considerations
- Assess for bleeding at every interaction — urine, stool, skin bruising, neurological changes, prolonged oozing from puncture sites
- Independent double check required for IV heparin infusions at most facilities
- Smart pump drug library with heparin-specific dose limits must be used for all IV heparin infusions
- Hold anticoagulants before invasive procedures — timing varies by drug half-life and procedure; coordinate with provider and procedural team
- Warfarin interactions — many drugs, foods (especially vitamin K-rich foods), and herbal supplements affect INR; consistent dietary vitamin K intake is more important than avoidance
- DOACs generally do not require routine lab monitoring but renal function must be monitored — dose adjustments or contraindications apply in renal impairment
Related Guides & References
Standards & sources
Fact-checked Jun 20, 2026This page is written to align with ACCP / ISTH Guidelines. It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →