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: A headache is not likely due to the anxiety about the chest pain, as anxiety usually causes other symptoms, such as palpitations, sweating, or trembling. A headache is more likely related to the vasodilating action of nitroglycerin, which causes increased blood flow to the brain.

Choice B reason: A headache does not indicate tolerance to the medication, as tolerance usually manifests as a reduced effect of the medication on relieving chest pain. A headache is more likely a sign of the medication's potency, as it indicates that the nitroglycerin is reaching the systemic circulation.

Choice C reason: A headache is an expected adverse effect of the medication, as nitroglycerin causes vasodilation of the cerebral vessels, which can result in increased intracranial pressure and pain. A headache is usually mild and transient, and can be relieved by taking analgesics, such as acetaminophen.

Choice D reason: A headache is not an indication of an allergy to the medication, as an allergic reaction usually causes other symptoms, such as rash, itching, swelling, or difficulty breathing. A headache is more likely a pharmacological effect of the medication, rather than an immunological response.

Choice A reason: Vomiting is not a specific sign of a hemolytic reaction, as it can be caused by many other factors, such as anesthesia, infection, or medication. Vomiting may occur in other types of transfusion reactions, such as allergic or febrile reactions, but it is not indicative of hemolysis.

Choice B reason: Flushing is not a specific sign of a hemolytic reaction, as it can be caused by many other factors, such as fever, infection, or medication. Flushing may occur in other types of transfusion reactions, such as allergic or febrile reactions, but it is not indicative of hemolysis.

Choice C reason: Dyspnea is often linked with transfusion-associated circulatory overload (TACO) or transfusion-related acute lung injury (TRALI). Both of these conditions primarily impact the respiratory system, leading to difficulty breathing. Although respiratory symptoms can accompany severe reactions, dyspnea is not a key feature of a hemolytic reaction.

Choice D reason: Hypotension is a significant indicator of an acute hemolytic reaction. When the recipient’s immune system attacks the donor red blood cells, widespread inflammatory and immune responses occur, leading to vascular collapse. This can manifest as sudden low blood pressure, which is life-threatening if not recognized and treated immediately. Alongside other findings such as fever, chills, flank pain, and hemoglobinuria, hypotension is a classic hallmark of hemolysis during transfusion.