Nokea
You prescribed digoxin for the treatment of chronic heart failure. The following is an indicator of improvement:
- A. Decreased heart rate
- B. Decreased parasympathetic flow
- C. Increased aldosterone
- D. Increased rennin secretion
Correct Answer: A
Rationale: Digoxin slows heart rate via vagal stimulation, indicating improved heart failure control.
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A 72-year-old man with long-standing heart failure managed with digoxin and a ß-blocker suddenly collapses in a shopping mall. Attempts to revive him are unsuccessful. Autopsy is performed. Which of the following changes in his heart would be expected to be noted?
- A. Dilated cardiac chambers
- B. Heart appears small
- C. Heart appears smooth
- D. Increased ability to eject blood
Correct Answer: A
Rationale: Chronic heart failure leads to dilated cardiomyopathy with enlarged chambers due to volume overload and remodeling.
Tick the drug, inhibiting oxidative phosphorylation in some species of helminthes:
- A. Niclosamide
- B. Piperazine
- C. Praziquantel
- D. Mebendazole
Correct Answer: A
Rationale: Niclosamide inhibits oxidative phosphorylation by blocking the electron transport chain in helminthes. It disrupts their energy production, leading to paralysis and death. Piperazine acts on GABA receptors, Praziquantel disrupts the parasite's tegument, and Mebendazole inhibits microtubule function. Therefore, Niclosamide is the correct choice for inhibiting oxidative phosphorylation in helminthes.
Which of the following antihyperlipidemic drugs would be relatively contraindicated in this patient?
- A. Cholestyramine
- B. Niacin
- C. Ezetimibe
- D. Lovastatin
Correct Answer: B
Rationale: The correct answer is B: Niacin. Niacin can cause hepatotoxicity and exacerbate liver conditions, which would be a concern in this patient. Cholestyramine (A) works in the intestines, Ezetimibe (C) inhibits cholesterol absorption, and Lovastatin (D) inhibits cholesterol synthesis in the liver, none of which are contraindicated in liver conditions.
The nurse is preparing to administer adenosine (Adenocard) to a patient who is experiencing an acute episode of paroxysmal supraventricular tachycardia. When giving this medication, which is important to remember?
- A. The onset of action occurs in 5 minutes.
- B. The medication must be given as a slow intravenous (IV) push.
- C. Asystole may occur for a few seconds after administration.
- D. The medication has a long half-life, and therefore duration of action is very long.
Correct Answer: C
Rationale: The correct answer is C. After administering adenosine, asystole may occur for a few seconds due to its rapid action on the heart's conduction system. Here's the rationale:
1. Adenosine works by slowing down conduction through the AV node, interrupting reentry pathways causing tachycardia.
2. This brief pause in electrical activity can cause a temporary stop in the heart's pumping action, resulting in asystole.
3. Asystole is expected and normal after adenosine administration, as it helps reset the heart's electrical activity and may terminate the tachycardia.
In contrast, options A and D are incorrect because adenosine has a rapid onset of action within seconds and a very short half-life of less than 10 seconds, leading to a quick duration of action. Option B is incorrect as adenosine should be given as a rapid IV push to ensure its effectiveness.
Tolerance and drug resistance can be a consequence of:
- A. Change in receptors, loss of them or exhaustion of mediators
- B. Increased receptor sensitivity
- C. Decreased metabolic degradation
- D. Decreased renal tubular secretion
Correct Answer: A
Rationale: The correct answer is A: Change in receptors, loss of them or exhaustion of mediators. Tolerance and drug resistance often occur due to changes in receptors, such as downregulation or desensitization, leading to decreased drug efficacy. Loss of receptors or exhaustion of mediators can also contribute to reduced drug response over time.
Explanation of why other choices are incorrect:
B: Increased receptor sensitivity would not lead to tolerance or drug resistance, as it would result in enhanced drug effects.
C: Decreased metabolic degradation would increase drug levels in the body, potentially leading to increased drug effects rather than tolerance.
D: Decreased renal tubular secretion may alter drug excretion but would not directly cause tolerance or drug resistance.