Anticoagulants, Antiplatelets and Thrombolytics
Prevent clots, stop clot growth, or dissolve clots
Anticoagulants
| Drug | Route / monitoring | Key points |
|---|---|---|
| Heparin (unfractionated) | IV infusion or SC; aPTT or anti-Xa; platelets | Fast onset; protocol-based dosing. HIT: platelets fall >50% (usually day 5–10) or new clots → stop all heparin (including flushes), use argatroban or bivalirudin. Safe in pregnancy. Antidote: protamine. |
| Enoxaparin (LMWH) | SC; usually no routine labs (anti-Xa in kidney disease, obesity, pregnancy) | Abdomen ≥2 in (5 cm) from the umbilicus; don't expel the air bubble in the prefilled syringe; don't rub. Lower dose if CrCl <30. Spinal/epidural hematoma risk around neuraxial anesthesia. |
| Warfarin | Oral; PT/INR | Blocks vitamin K–dependent factors (II, VII, IX, X). Takes days to work: overlap with heparin/LMWH until INR is therapeutic. Teratogenic (OK in breastfeeding). Keep vitamin K intake consistent (don't avoid greens, just keep them steady). Many interactions: antibiotics, amiodarone, NSAIDs, alcohol, herbals. |
| DOACs: apixaban, rivaroxaban, edoxaban, dabigatran | Oral; no routine INR | Fewer interactions and fewer brain bleeds than warfarin (GI bleeding can be higher with some). Not for mechanical heart valves or pregnancy. Rivaroxaban 15/20 mg with food. Dabigatran: keep in the original bottle, don't open capsules. Doses adjusted for kidney function. |
Antiplatelets
| Aspirin | Irreversible; effect lasts the platelet's life (7–10 days) |
| Clopidogrel | Prodrug; omeprazole/esomeprazole reduce its effect (pantoprazole preferred) |
| Prasugrel | Not with prior stroke/TIA; caution age ≥75 or weight <60 kg |
| Ticagrelor | Twice daily; shortness of breath; keep aspirin ≤100 mg |
| Cilostazol | Leg claudication; contraindicated in HF |
After a coronary stent: never stop antiplatelets without the cardiologist (stent thrombosis).
Thrombolytics
Alteplase (stroke, STEMI, massive PE); tenecteplase (stroke, STEMI); reteplase (STEMI only). Dissolve existing clots.
Contraindications (examples): active bleeding, any prior brain hemorrhage, recent stroke, surgery or trauma, brain tumor, severe uncontrolled BP, bleeding disorder.
Nursing: place IV lines before; avoid IM injections and new punctures; neuro checks; watch for bleeding (gums, IV sites, urine, stool, neuro change). Stroke timing: within 4.5 h of last known well.
Bleeding precautions (teach)
- Soft toothbrush; electric razor; gentle flossing with waxed floss.
- Avoid contact sports and fall hazards.
- No NSAIDs or aspirin unless prescribed; check with the pharmacist before herbal products.
- Report: black or bloody stools, blood in urine, coffee-ground vomit, nosebleeds that won't stop, unusual bruising, severe headache.
- Wear medical ID; tell all providers and the dentist.
Memory hook
Warfarin → PT/INR ("WarPed Time"); heparin → aPTT.
Warfarin needs Waiting (slow onset); Heparin Happens fast.
Warfarin needs Waiting (slow onset); Heparin Happens fast.