Pharmacology Practice Test #10: Anticoagulants

Answer: B. "Keep eating about the same amount of these foods each week, and tell your provider before you make a big change in your diet."

Rationale: Warfarin works by blocking the vitamin K-dependent clotting factors, so vitamin K in food can change its effect. The goal is a consistent intake, not avoidance. When vitamin K intake stays steady, the prescriber can set a warfarin dose that keeps the INR in the client's target range. A sudden increase in leafy greens can lower the INR and raise clot risk; a sudden decrease can raise the INR and bleeding risk. Option A is wrong because cutting out these foods is unnecessary and would itself shift the INR. Option C is wrong because clients should never try to adjust their own INR with food; an abnormal INR is reported to the prescriber, who decides on dose changes. Option D is wrong because vitamin K-rich foods such as spinach, kale, broccoli and collard greens do affect warfarin.

Answer: D. "Acetaminophen is usually the preferred choice, but check with your provider or pharmacist about the amount, and avoid ibuprofen, naproxen and aspirin unless your provider approves them."

Rationale: NSAIDs such as ibuprofen and naproxen, and aspirin, inhibit platelet function and can irritate the stomach lining. Combined with warfarin they raise the risk of serious bleeding, especially GI bleeding. Acetaminophen is generally the preferred over-the-counter analgesic for clients on warfarin, but regular or high intake can raise the INR in some clients, so the amount should be confirmed with the provider or pharmacist and any change in use reported. Options A, B and C are wrong because each involves a drug that adds to bleeding risk; taking ibuprofen with food does not remove the antiplatelet effect, and aspirin is an antiplatelet drug, not simply a mild pain reliever.

Answer: A. Unfractionated heparin: protamine sulfate

Rationale: Protamine sulfate binds unfractionated heparin and neutralizes it; it only partly reverses low-molecular-weight heparins such as enoxaparin. Warfarin is reversed with vitamin K (phytonadione), and for serious bleeding a prothrombin complex concentrate may be given as well, according to the prescriber and facility protocol. Idarucizumab is the specific reversal agent for dabigatran, a direct thrombin inhibitor. The factor Xa inhibitors apixaban and rivaroxaban have their own reversal options, chosen by the provider and facility protocol. Option B is wrong because protamine does not reverse warfarin. Option C is wrong because vitamin K does not reverse dabigatran. Option D is wrong because idarucizumab is specific to dabigatran and has no effect on enoxaparin.

Answer: C. Notify the provider or anesthesia team immediately and hold the next enoxaparin dose until the client is evaluated

Rationale: Low-molecular-weight heparins such as enoxaparin carry a boxed warning for epidural or spinal hematoma in clients with neuraxial anesthesia or an epidural catheter. A hematoma can compress the spinal cord and cause permanent paralysis, so new or worsening numbness, leg weakness, back pain, or bowel or bladder dysfunction must be reported immediately. Prompt imaging and surgical decompression may be needed. Anticoagulant timing around epidural placement and removal follows the facility protocol and anesthesia guidance. Option A is wrong because waiting delays treatment of a time-sensitive emergency. Option B is wrong because the local anesthetic could explain some numbness, but a new bilateral motor change in a client on enoxaparin must be assumed to be a hematoma until proven otherwise, and the decision belongs to the anesthesia team. Option D is wrong because walking a client with new leg weakness creates a fall risk and does not address the cause.

Answer: B. "Please do not stop clopidogrel on your own. Ask your dentist to talk with your cardiologist before the procedure."

Rationale: After a coronary stent, dual antiplatelet therapy (a P2Y12 inhibitor such as clopidogrel plus aspirin) prevents stent thrombosis, a clot inside the stent that can cause a heart attack or death. The risk is highest in the months after placement, and stopping either drug early without a plan raises that risk sharply. Many dental procedures can be done without stopping antiplatelet therapy, using local measures to control bleeding. Any decision to pause, and for how long, belongs to the cardiologist in coordination with the dentist. Options A, C and D are wrong because they all involve the client stopping an antiplatelet drug without the cardiologist's direction; Option A also gives a fixed number of days that is not universal.

Answer: D. Stop the alteplase infusion and notify the provider or stroke team immediately

Rationale: A sudden severe headache, new nausea and vomiting, acute hypertension or a decline in neurological status during or after thrombolytic therapy suggests intracranial hemorrhage, the most feared complication of alteplase. Current AHA/ASA stroke guidelines direct that the infusion be stopped and the provider notified at once; an emergency head CT and blood work are expected next, and blood pressure is managed according to the stroke protocol. Option A is wrong because treating the headache masks a warning sign and delays action. Option B is wrong because slowing the infusion still delivers the thrombolytic; it should be stopped. Option C is wrong because positioning and an antiemetic do not address the likely bleed.

Answer: A. "Warfarin takes several days to reach its full effect, so the heparin protects you until your INR has reached the target range your provider sets."

Rationale: Warfarin reduces the production of new vitamin K-dependent clotting factors, but factors already in the blood take days to clear, so its full anticoagulant effect is delayed. Heparin acts immediately. The two are overlapped for several days and until the INR is in the therapeutic range the prescriber has set for that client, then heparin is stopped. Option B is wrong because neither heparin nor warfarin dissolves an existing clot; they prevent the clot from growing and new clots from forming while the body breaks the clot down. Option C is wrong because heparin does not protect against warfarin side effects. Option D is wrong because heparin is a short-term drug here, and the length of warfarin therapy depends on the cause of the clot and the prescriber's plan.

Answer: C. "Swallow the capsule whole with a full glass of water. Don't open, crush or chew it, and talk with your provider if you can't swallow it."

Rationale: The labeling for dabigatran states the capsules must be swallowed whole. Opening, chewing or crushing them can greatly increase the amount of drug absorbed and raise the risk of bleeding. Taking it with a full glass of water also helps reduce stomach upset. Dabigatran capsules should be kept in the original bottle or blister pack to protect them from moisture, which is why Option B is wrong; check product labeling for specific storage instructions. If the client cannot swallow the capsule, the prescriber may choose a different anticoagulant. Options A and D are wrong because opening or chewing the capsule increases absorption.

Answer: B. "Call 911 or get to the emergency department now. Bring the medication list."

Rationale: Clients taking anticoagulants are at higher risk of bleeding inside the skull after even a minor head injury, and older adults are especially vulnerable. A worsening headache and new or increasing confusion are signs of a possible intracranial hemorrhage, which needs emergency imaging and, if confirmed, possible reversal of the anticoagulant. Bringing the medication list (including the time of the last dose) helps the emergency team decide on reversal. Options A and D are wrong because they delay emergency care for a neurological change. Option C is wrong because holding a future dose does nothing for a bleed that may already be happening, and the decision about the anticoagulant belongs to the provider.

Answer: D. Notify the provider promptly so pregnancy testing and the anticoagulation plan can be addressed right away

Rationale: Warfarin crosses the placenta and can cause birth defects (warfarin embryopathy), fetal bleeding and pregnancy loss. It is generally avoided in pregnancy, with rare exceptions such as some clients with mechanical heart valves, decided by specialists. A possible pregnancy needs prompt confirmation, and the provider will usually switch the client to a low-molecular-weight heparin, which does not cross the placenta. Clients of childbearing potential on warfarin should be counseled about reliable contraception. Option A is wrong because warfarin is not considered safe in pregnancy. Option B is wrong because folic acid does not prevent warfarin's effects. Option C is wrong because stopping all anticoagulation on her own would leave her unprotected from another clot; the change must be directed by the provider.