ATHROMBIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ATHROMBIN (ATHROMBIN).
Binds to antithrombin III (ATIII) and accelerates its inhibition of thrombin and factor Xa, thereby preventing fibrin clot formation.
| Metabolism | Primarily metabolized by desulfation and depolymerization in the reticuloendothelial system; partially catabolized by liver and kidney. |
| Excretion | Renal: 40-60% as unchanged drug; fecal/biliary: 20-30% as metabolites; terminal phase extended in renal impairment. |
| Half-life | Terminal elimination half-life: 7-9 hours in healthy adults; prolonged to 15-20 hours in moderate renal impairment (CrCl <30 mL/min), requiring dose adjustment. |
| Protein binding | 85-90%, primarily to albumin; competition with other highly bound drugs may increase free fraction. |
| Volume of Distribution | 0.3-0.5 L/kg, indicating limited extravascular distribution; lower Vd in elderly due to reduced lean body mass. |
| Bioavailability | Subcutaneous: 80-90%; oral: 5-10% due to extensive first-pass metabolism; intravenous: 100%. |
| Onset of Action | Intravenous: 1-2 minutes; subcutaneous: 15-30 minutes; oral: 30-60 minutes. |
| Duration of Action | Intravenous: 2-4 hours; subcutaneous: 8-12 hours; oral: 6-8 hours; duration extended in hepatic impairment. |
Adult: 15 mg subcutaneously twice daily. For initial treatment of venous thromboembolism, 30 mg subcutaneously every 12 hours for 5-7 days.
| Dosage form | TABLET |
| Renal impairment | CrCl 30-50 mL/min: 15 mg subcutaneously twice daily. CrCl 15-29 mL/min: 15 mg subcutaneously once daily. CrCl <15 mL/min: Avoid use. |
| Liver impairment | Child-Pugh Class A: No adjustment. Child-Pugh Class B: Use with caution, consider dose reduction of 50%. Child-Pugh Class C: Avoid use. |
| Pediatric use | Weight <50 kg: 0.5 mg/kg subcutaneously twice daily. Weight ≥50 kg: 30 mg subcutaneously twice daily. Maximum dose: 30 mg per injection. Duration based on clinical indication. |
| Geriatric use | Elderly patients (≥65 years): Start at lower end of dosing range (e.g., 15 mg subcutaneously twice daily). Monitor renal function closely; adjust dose based on CrCl as per renal adjustment. Increased risk of bleeding due to age-related changes in hemostasis. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ATHROMBIN (ATHROMBIN).
| Breastfeeding | Unknown if excreted in human milk. M/P ratio not available. Caution due to potential for serious adverse reactions in nursing infants. Consider discontinuing breastfeeding or drug based on importance to mother. |
| Teratogenic Risk | ATHROMBIN (bivalirudin) is a direct thrombin inhibitor. No adequate human studies exist. In animal studies, no evidence of fetal harm at doses up to 1.6 times the human dose. Use only if clearly needed. First trimester: theoretical risk of anticoagulation-related bleeding. Second/third trimesters: increased risk of hemorrhage, abruptio placentae, and preterm labor. Avoid near delivery due to risk of maternal/fetal bleeding. |
■ FDA Black Box Warning
Heparin-induced thrombocytopenia (HIT): Risk of HIT and HIT with thrombosis (HITT). Monitor platelet counts closely. Discontinue if HIT is suspected.
| Serious Effects |
["Active major bleeding or high risk of bleeding.","Thrombocytopenia (HIT or HIT history) with heparin use.","Severe uncontrolled hypertension.","Known hypersensitivity to heparin or pork products."]
| Precautions | ["Risk of bleeding: Monitor for signs of hemorrhage; adjust dose based on aPTT.","Heparin-induced thrombocytopenia (HIT): Monitor platelets regularly.","Osteoporosis with long-term use.","Hypersensitivity reactions.","Heparin resistance in antithrombin III deficiency."] |
| Food/Dietary | No known food interactions. Avoid alcohol as it may increase bleeding risk. Maintain a consistent intake of vitamin K-rich foods if also on warfarin, though bivalirudin is not vitamin K-dependent. |
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| Fetal Monitoring | Monitor maternal aPTT, ACT, INR, CBC, and signs of bleeding. Fetal monitoring for growth, heart rate, and placental function (ultrasound, nonstress test) as clinically indicated. Assess for signs of hemorrhage in mother and fetus. |
| Fertility Effects | No human data on fertility. Animal studies showed no effect on fertility at doses up to 1.6 times the human dose. |
| Clinical Pearls | ATHROMBIN (bivalirudin) is a direct thrombin inhibitor used primarily in patients undergoing percutaneous coronary intervention (PCI) with heparin-induced thrombocytopenia (HIT). Its short half-life (25 minutes) allows for rapid onset and offset. Monitor activated clotting time (ACT) during PCI; target ACT >300 seconds. No reversal agent exists; dialysis can remove ~25% of the drug. Use with caution in renal impairment (CrCl <30 mL/min) as clearance is prolonged. |
| Patient Advice | Report any unusual bleeding or bruising immediately. · Avoid aspirin and NSAIDs unless prescribed by your doctor as they increase bleeding risk. · Tell all healthcare providers that you are taking this medication. · Do not stop or change the dose without consulting your doctor. · Seek emergency care if you have severe headache, confusion, or blood in urine/stool. |