Which of the following opioid analgesics is used as a preferred and rational antitussive agent?

Correct Answer: B

Rationale: The correct answer is B) Codeine. Codeine is a preferred and rational antitussive agent because it acts directly on the brain to suppress the cough reflex. It is commonly used in cough syrups and provides relief for non-productive coughs. Unlike other opioids like Morphine (A), Meperidine (C), and Methadone (D), codeine has a lower potential for abuse and addiction due to its weaker opioid properties. Morphine (A) is a potent opioid analgesic primarily used for pain management, while Meperidine (C) is more commonly used for acute pain relief or anesthesia due to its short duration of action and potential for toxicity. Methadone (D) is primarily used in opioid addiction treatment programs due to its long-acting nature and ability to suppress withdrawal symptoms. In an educational context, understanding the specific uses and properties of different opioid analgesics is crucial for safe and effective clinical practice. Nurses must be able to differentiate between these medications to provide appropriate care for patients with varying needs, such as pain management, cough suppression, or addiction treatment. This knowledge ensures accurate medication administration and promotes patient safety and optimal outcomes.

Correct Answer: B

Rationale: The correct answer is B) 30-40 hours. Ethosuximide is a medication commonly used to treat absence seizures. Understanding the half-life of a drug is crucial in determining dosing intervals and potential drug accumulation in the body. Option A) 10-20 hours is incorrect because it is too short for ethosuximide, which has a longer half-life due to its pharmacokinetic properties. Option C) 50-60 hours and Option D) 60-70 hours are both incorrect as they overestimate the half-life of ethosuximide. A half-life of 50-70 hours would indicate a much slower rate of elimination than what is typically seen with this drug. Educationally, knowing the half-life of drugs is essential for nurses and healthcare professionals in providing safe and effective patient care. It informs medication administration schedules and helps in understanding the duration of drug action in the body. Understanding drug half-lives also aids in predicting potential drug interactions and side effects related to drug accumulation.

Correct Answer: A

Rationale: Local anesthetics primarily affect membrane excitability by inhibiting sodium (Na+) channel inactivation, making option A the correct answer. This mechanism blocks the influx of sodium ions into the cell, preventing the generation and propagation of action potentials. By doing so, local anesthetics effectively block the transmission of pain signals along nerves. Options B and C are incorrect because local anesthetics do not increase sodium (Na+) conductance or potassium (K+) conductance. Instead, they work by reducing the excitability of neurons through their action on sodium channels. In an educational context, understanding the mechanism of action of local anesthetics is crucial for healthcare professionals, especially those working in fields such as anesthesia, surgery, and pain management. Knowing how these drugs affect membrane excitability helps in determining appropriate dosages, predicting potential side effects, and ensuring safe and effective administration to patients undergoing various procedures. This knowledge is also essential for passing exams like the NCLEX, where pharmacological principles play a significant role in assessing a candidate's readiness to practice safely as a nurse.

Correct Answer: D

Rationale: In the context of post-anaesthesia emergency delirium, the correct answer is D) All the above (Enflurane, Isoflurane, Nitrous oxide). This is because all of these anesthetic agents can potentially lead to emergence delirium, a common side effect characterized by agitation, confusion, and disorientation as the patient emerges from anesthesia. Enflurane and Isoflurane are both inhalational anesthetics known to increase the risk of emergence delirium, especially in susceptible individuals such as elderly patients or those with a history of cognitive impairment. Nitrous oxide, when used as part of the anesthetic gas mixture, can also contribute to emergence delirium. It is important for healthcare providers, especially those involved in post-anesthesia care, to be aware of the potential side effects of different anesthetic agents in order to promptly recognize and manage complications like emergence delirium. Understanding the risks associated with specific medications helps in ensuring patient safety and providing optimal care throughout the perioperative period.

Correct Answer: A

Rationale: The correct answer is A) Metabolites are important to the action of these drugs. Rationale: Antipsychotics, also known as neuroleptics, exert their therapeutic effects through interactions with various neurotransmitter systems in the brain. Metabolites play a crucial role in the action of antipsychotic drugs. These metabolites can be active and contribute significantly to the overall pharmacological effects of the drugs. Understanding the metabolism of antipsychotics is essential for predicting their efficacy, side effects, and potential drug interactions. Explanation of Incorrect Options: B) Haloperidol has higher systemic availability than thioridazine - This statement is incorrect as systemic availability is not determined solely by the drug but also by factors such as route of administration, metabolism, and protein binding. C) Elimination half-lives of these drugs range between 3-6 hours - This statement is incorrect as the elimination half-lives of antipsychotic drugs vary widely, ranging from hours to days depending on the specific drug. D) This group of drugs generally has short clinical duration of action - This statement is incorrect as some antipsychotics have long-acting formulations that provide sustained release and prolonged duration of action. Educational Context: Understanding the pharmacology of antipsychotic drugs is crucial for healthcare professionals, especially nurses, who play a vital role in administering these medications and monitoring patients for therapeutic effects and adverse reactions. Knowledge of how antipsychotics work at a molecular level, including the role of metabolites, helps ensure safe and effective patient care in psychiatric and other healthcare settings.