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?

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.

Correct Answer: B

Rationale: The correct answer is B: FALSE. Intravenous injections are not suitable for oily solutions due to the risk of causing pulmonary embolism or other serious complications. Oily solutions can lead to blockages in the blood vessels, posing significant health risks. Other choices are incorrect because intravenous injections should not be used for all oily solutions (Choice C) or none of them (Choice D) due to the potential harm they can cause.

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.

Correct Answer: C

Rationale: The correct answer is C: Bupivacaine. Bupivacaine is used for spinal anesthesia due to its long duration of action and potency. It provides effective anesthesia for surgeries and pain management. Procaine (A) is not commonly used for spinal anesthesia due to its short duration of action. Lidocaine (B) is used more for regional anesthesia and nerve blocks. Dupivacaine (D) is a duplicate choice and not a valid option. In summary, bupivacaine is the preferred choice for spinal anesthesia due to its duration of action and efficacy.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Succinylcholine is a depolarizing agent because it acts as a nicotinic acetylcholine receptor agonist. 2. It causes initial depolarization of the motor end plate leading to muscle fasciculations. 3. By maintaining depolarization, it prevents repolarization and muscle contraction, inducing muscle relaxation. Summary: A. Vecuronium is a non-depolarizing agent that blocks acetylcholine receptors. B. Scopolamine is an anticholinergic drug used for motion sickness. D. Hexamethonium is a ganglionic blocker used for hypertension.