A nurse is obtaining a medical history from a client who is to start warfarin therapy and currently uses herbal supplements at home. The nurse should inform the client that which of the following herbal supplements can interact adversely with warfarin?

Choice A reason: This is incorrect because aspirin is not a suitable medication for preventing venous thromboembolism (VTE) in a client who is postoperative following hip arthroplasty. Aspirin is a nonsteroidal anti-inflammatory drug (NSAID) that has antiplatelet and analgesic effects, but it is not as effective as anticoagulants for VTE prophylaxis.

Choice B reason: This is incorrect because alteplase is not a medication for preventing VTE, but for treating it. Alteplase is a thrombolytic agent that dissolves existing blood clots by activating plasminogen. It is used for acute ischemic stroke, myocardial infarction, and massive pulmonary embolism, but it has a high risk of bleeding and is contraindicated in clients who have had recent surgery.

Choice C reason: This is incorrect because clopidogrel is not a medication for preventing VTE, but for preventing arterial thrombosis. Clopidogrel is an antiplatelet agent that inhibits the adenosine diphosphate (ADP) receptor on platelets, preventing their aggregation. It is used for clients who have had acute coronary syndrome, percutaneous coronary intervention, or ischemic stroke, but it is not effective for VTE prophylaxis.

Choice D reason: This is correct because enoxaparin is a medication for preventing VTE in a client who is postoperative following hip arthroplasty. Enoxaparin is a low molecular weight heparin (LMWH) that inhibits factor Xa and thrombin, preventing the formation of fibrin. It is administered subcutaneously once or twice daily and does not require routine laboratory monitoring. It has a lower risk of bleeding and heparin-induced thrombocytopenia (HIT) than unfractionated heparin.

Choice A reason: Platelets 190,000/mm3 is within the normal range of 150,000 to 450,000/mm3. This result does not indicate a bleeding risk or a need to adjust the warfarin dose.

Choice B reason: Hct 44% is within the normal range of 37% to 47% for females and 42% to 52% for males. This result does not indicate anemia or polycythemia, which could affect the warfarin therapy.

Choice C reason: PT 45 seconds is above the normal range of 11 to 13.5 seconds. This result indicates that the blood is taking too long to clot, which increases the risk of bleeding. The nurse should notify the provider and expect a decrease in the warfarin dose.

Choice D reason: Hgb 16 g/dL is within the normal range of 12 to 16 g/dL for females and 14 to 18 g/dL for males. This result does not indicate anemia or polycythemia, which could affect the warfarin therapy.