Version July 2025
| Absolute contraindications to anticoagulation and risk factors for bleeding | Examples and qualifying remarks |
| Absolute contraindications* | |
| Active major bleeding | |
| Acute intracranial or spinal hemorrhage | |
| Major trauma | Eg, intra-abdominal or intrathoracic injuries related to high-speed motor vehicle collision or gunshot wounds |
| Recent, planned, or emergency high-bleeding-risk surgery/procedure | Eg, emergency abdominal aortic aneurysm repair, exploratory laparotomy, craniotomy |
| Severe bleeding diathesis | Eg, disseminated intravascular coagulation or decompensated cirrhosis (often presenting with prolonged coagulation times and low platelets, though presentation may vary) |
| Severe thrombocytopenia | Eg, platelet counts <25,000/microL |
| Relative contraindications¶ | |
| Intracranial or spinal tumors | |
| Recurrent gastrointestinal bleeding | Eg, from multiple gastrointestinal telangiectasias |
| Large abdominal aortic aneurysm with concurrent severe hypertension | |
| Stable aortic dissection | |
| Recent, planned, or emergent low-bleeding-risk surgery/procedure | Eg, cholecystectomy, knee or hip replacement |
| Other risk factors for bleeding¶ | |
| Older age | |
| Non-severe thrombocytopenia | Eg, platelet counts >25,000 to 50,000/microL |
| History of bleeding | |
| Active cancerΔ | Patients with cancer are at increased risk of bleeding (as well as thrombosis) |
| Acute ischemic stroke◊ | Anticoagulation initiation and timing is individualized in acute ischemic stroke |
| Comorbidities | Patients with liver failure, kidney failure, and diabetes are at increased risk of bleeding |
| Concomitant medications | Eg, antiplatelets or nonsteroidal anti-inflammatory drugs, aspirin |
| Anemia | Eg, hemoglobin <10 g/dL (100 g/L) |
| Excess alcohol use | |
| History of poor anticoagulant control | |
| Fall risk or history of frequent falls | |
* Absolute contraindications: Anticoagulation is not initiated when an active absolute contraindication to anticoagulation is present. Individual judgement is required in assessing the recency and severity of each factor.
¶ Relative contraindications and bleeding risk factors: Relative contraindications and risk factors do not portend the same degree of bleeding risk, vary with the severity of the risk factor, recency of occurrence, and how effectively previous bleeding was controlled.
Δ Active cancer is defined by the International Society on Thrombosis and Hemostasis as cancer diagnosed within the previous 6 months; recurrent, regionally advanced, or metastatic cancer; cancer for which treatment has been administered within 6 months; or hematologic cancer that is not in complete remission.
◊ Refer to UpToDate content on prevention and treatment of venous thromboembolism in patients with acute stroke.
