What enzyme cleaves plasminogen to form active plasmin?

Correct Answer: A

Rationale: Plasminogen is cleaved by the enzyme plasmin to form active plasmin. Plasminogen is the inactive precursor of plasmin, which is responsible for breaking down fibrin clots. Fibrinogen is a protein involved in blood clotting but does not cleave plasminogen to form plasmin. Thrombin is also involved in blood clotting but does not directly cleave plasminogen. Streptokinase is a bacterial enzyme that can activate plasminogen, but it does so indirectly by forming a complex with plasminogen.

Correct Answer: A

Rationale: The correct answer is A) Increase. Explanation: When a patient on oral anticoagulant therapy is started on sulfamethoxazole-trimethoprim, a medication combination known to interact with anticoagulants, it can lead to an increase in the international normalized ratio (INR). Sulfamethoxazole-trimethoprim can inhibit the metabolism of warfarin, increasing its anticoagulant effect and leading to a higher INR. This interaction can potentially increase the risk of bleeding in patients. Why others are wrong: B) Decrease: This is incorrect because the interaction between sulfamethoxazole-trimethoprim and oral anticoagulants typically leads to an increase in the INR due to enhanced anticoagulant effect. C) Remain unchanged: This is incorrect as the interaction between these medications is known to impact the INR values, leading to changes rather than remaining stable. Educational context: Understanding drug interactions is crucial in healthcare to prevent adverse effects and ensure optimal patient care. Healthcare providers need to be aware of potential interactions between medications, like the one discussed here, to make informed decisions when prescribing or adjusting drug regimens for patients on anticoagulant therapy. Monitoring INR levels and adjusting anticoagulant doses accordingly can help manage and prevent complications from drug interactions.

Correct Answer: B

Rationale: In the context of digitalis-induced arrhythmias, the drug of choice is Phenytoin (Option B). Phenytoin is a class IB antiarrhythmic agent that helps stabilize cardiac cell membranes and prevent further arrhythmias caused by digitalis toxicity. Propranolol (Option A) is a non-selective beta-blocker and can worsen digitalis-induced arrhythmias by further slowing conduction through the AV node. Xylocaine (Option C) is a local anesthetic and not indicated for the treatment of digitalis-induced arrhythmias. Phenylephrine (Option D) is a sympathomimetic agent and does not address the underlying mechanism of digitalis toxicity. In an educational context, it is important for healthcare professionals to understand the appropriate pharmacological interventions for various types of arrhythmias. Digitalis-induced arrhythmias require specific management strategies, and selecting the correct antiarrhythmic agent like Phenytoin can prevent further complications and improve patient outcomes. Understanding the mechanisms of action of different drugs and their effects on cardiac electrophysiology is crucial in making informed treatment decisions in clinical practice.

Correct Answer: C

Rationale: In this scenario, the correct answer is C) Hydrochlorothiazide decreases potassium, increasing the risk of digoxin toxicity. Hydrochlorothiazide is a diuretic that can lead to hypokalemia (low potassium levels) due to its mechanism of action of increasing the excretion of potassium in the urine. Digoxin, on the other hand, is a medication used to treat heart conditions but has a narrow therapeutic range. Low potassium levels can increase the risk of digoxin toxicity as digoxin's effects are potentiated in the presence of low potassium levels. Option A is incorrect because hydrochlorothiazide does not increase digoxin levels; in fact, it can lead to decreased levels due to increased excretion. Option B is incorrect as hydrochlorothiazide can decrease digoxin levels but the focus here is on the risk of toxicity due to hypokalemia. Option D is incorrect as there is no evidence to support that digoxin increases the effectiveness of hydrochlorothiazide. From an educational perspective, this question highlights the importance of understanding potential drug interactions and adverse effects when administering multiple medications to a patient. It underscores the need for healthcare providers to monitor electrolyte levels, especially potassium, in patients taking both hydrochlorothiazide and digoxin to prevent adverse outcomes like digoxin toxicity.

Correct Answer: C

Rationale: In the context of switching a client from warfarin to Pradaxa, the correct indication to give Pradaxa when the INR is less than 2 is C. This is because Pradaxa, a direct thrombin inhibitor, does not require monitoring of INR levels like warfarin does. Pradaxa's dosing is not influenced by INR levels, making it a more convenient option for patients. Option A, waiting for the INR to normalize, is incorrect because Pradaxa does not rely on INR monitoring. Option B, giving Pradaxa when warfarin is stopped, is incorrect as it does not consider the patient's current INR status. Option D, giving Pradaxa 2 days after stopping warfarin, is incorrect as there is no specific waiting period required between stopping warfarin and starting Pradaxa. Educationally, this question highlights the differences in monitoring requirements between warfarin and newer anticoagulants like Pradaxa. It emphasizes the importance of understanding the unique characteristics of each medication to ensure safe and effective patient care. Nurses need to be knowledgeable about these nuances to provide optimal care and prevent medication errors.