Nokea
Which of the following inhaled anesthetics decreases metheonine synthase activity and causes megaloblastic anemia?
- A. Desflurane
- B. Halothane
- C. Nitrous oxide
- D. Soveflurane
Correct Answer: C
Rationale: The correct answer is C: Nitrous oxide. Nitrous oxide inhibits methionine synthase activity by inactivating vitamin B12, leading to megaloblastic anemia. Desflurane, Halothane, and Sevoflurane do not affect methionine synthase or cause megaloblastic anemia. Nitrous oxide is the only anesthetic among the choices known for this specific mechanism of action.
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A 47-year-old man is recovering from a heart attack. He takes a daily baby aspirin to prevent further attacks. He also takes phenelzine for refractory panic disorder. Which of the following characteristics do aspirin and phenelzine share?
- A. Antiplatelet activity
- B. Irreversible inhibition
- C. Inhibit the same enzyme
- D. Should not be taken with tyramine-containing foods
Correct Answer: B
Rationale: Aspirin irreversibly inhibits COX-1, and phenelzine irreversibly inhibits MAO, sharing the characteristic of irreversible enzyme inhibition.
A 67-year-old man with insulin-dependent diabetes mellitus, hypertension, and congestive heart failure develops exacerbation of heart failure symptoms. Pathophysiology of this condition that relates to potential roles of drug therapy include which of the following?
- A. Peripheral nervous system activity
- B. Loss of cardiac myocytes
- C. Muscle hyperplasia
- D. Muscle inflammatory scar formation
Correct Answer: B
Rationale: Loss of cardiac myocytes from infarction or chronic stress drives heart failure, targetable by drugs like ACE inhibitors or ß-blockers.
Indicate the drug belonging to fibrinoliytic inhibitors:
- A. Aminocapronic acid
- B. Ticlopidine
- C. Streptokinase
- D. Vitamin K
Correct Answer: A
Rationale: Step-by-step rationale for why Aminocaproic acid (A) is the correct answer:
1. Aminocaproic acid is a fibrinolytic inhibitor that prevents the breakdown of blood clots.
2. It works by inhibiting the activation of plasminogen to plasmin, which is essential for clot dissolution.
3. Therefore, Aminocaproic acid belongs to the class of fibrinolytic inhibitors.
Summary of why the other choices are incorrect:
- Ticlopidine (B) is a platelet aggregation inhibitor, not a fibrinolytic inhibitor.
- Streptokinase (C) is a fibrinolytic drug that promotes clot breakdown, not an inhibitor.
- Vitamin K (D) is essential for clotting factors synthesis, not a fibrinolytic inhibitor.
Which of the following drugs was most likely administered to the patient to prevent further fibrillatory episodes?
- A. Mexiletine
- B. Sotalol
- C. Quinidine
- D. Amiodarone
Correct Answer: D
Rationale: The correct answer is D: Amiodarone. Amiodarone is a potent antiarrhythmic drug commonly used to prevent fibrillatory episodes like atrial fibrillation. It has a broad spectrum of action, affecting multiple ion channels to stabilize cardiac rhythm. Mexiletine (A) is used for ventricular arrhythmias, not fibrillatory episodes. Sotalol (B) is also used for ventricular arrhythmias and can actually increase the risk of torsades de pointes in patients with atrial fibrillation. Quinidine (C) is an older antiarrhythmic that is less commonly used due to its potential for proarrhythmic effects.
The nurse is reviewing the food choices of a patient who is taking a monoamine oxidase inhibitor (MAOI). Which food choice would indicate the need for additional teaching?
- A. Orange juice
- B. Fried eggs over-easy
- C. Salami and Swiss cheese sandwich
- D. Biscuits and honey
Correct Answer: C
Rationale: The correct answer is C: Salami and Swiss cheese sandwich. This is because salami and Swiss cheese are high in tyramine, which can cause a hypertensive crisis in patients taking MAOIs due to their inhibitory effect on monoamine oxidase. Orange juice (A) does not contain tyramine. Fried eggs over-easy (B) and biscuits with honey (D) are also safe choices as they do not contain high levels of tyramine. Therefore, the need for additional teaching is indicated by the selection of foods high in tyramine like salami and Swiss cheese.