Suxamethonium

Correct Answer: D

Rationale: Rationale: Suxamethonium, also known as succinylcholine, is a depolarizing neuromuscular blocking agent used for rapid muscle relaxation during anesthesia. The correct answer is D) Should not be administered to burn patients after 24 hours. This is because burn patients are at risk of developing hyperkalemia due to the release of potassium from damaged muscle cells, and the use of suxamethonium can further increase this risk by causing further potassium release. Option A) Is a non-depolarizing neuromuscular blocking agent is incorrect because suxamethonium is a depolarizing agent, not non-depolarizing. Option B) Is contraindicated in all eye operations is incorrect as suxamethonium is commonly used in eye surgeries due to its rapid onset and short duration of action. Option C) Stimulates cardiac muscarinic receptors and autonomic ganglia is incorrect. Suxamethonium acts primarily at the neuromuscular junction and does not directly stimulate cardiac muscarinic receptors or autonomic ganglia. Educational context: Understanding the pharmacology of CNS stimulants like suxamethonium is crucial for healthcare providers, especially anesthesiologists and critical care nurses. Knowledge of contraindications, adverse effects, and special considerations is essential for safe and effective drug administration. In the case of burn patients, the potential for hyperkalemia with suxamethonium highlights the importance of individualizing drug therapy based on patient-specific factors.

Correct Answer: D

Rationale: In this CNS stimulants drugs pharmacology quiz question, the correct statement about thiopentone is option D: "Anesthetic action is terminated by redistribution from CNS to other highly vascularized tissues." The correct answer is D because thiopentone, a barbiturate, is a highly lipid-soluble drug that rapidly crosses the blood-brain barrier to exert its anesthetic effects in the central nervous system (CNS). Its action is terminated by redistribution from the CNS to other highly vascularized tissues, such as the muscle and fat, leading to a rapid decrease in its CNS concentration and subsequent termination of its anesthetic effects. Option A (Is not lipid soluble) is incorrect because thiopentone is indeed highly lipid soluble, which allows it to quickly penetrate the CNS. Option B (Can be used IM or IV to induce anesthesia) is incorrect because thiopentone is typically administered intravenously due to its irritant properties and the risk of tissue damage if given intramuscularly. Option C (Has good analgesic properties) is incorrect because thiopentone is primarily an ultrashort-acting anesthetic agent with minimal analgesic properties. It is used for induction of anesthesia rather than for analgesia. This educational context is crucial for healthcare professionals, particularly anesthesiologists and pharmacists, who need to understand the pharmacokinetics and pharmacodynamics of CNS stimulants like thiopentone to ensure safe and effective administration in clinical practice. Understanding how thiopentone's anesthetic effects are terminated by redistribution helps in optimizing dosing regimens and managing potential side effects associated with its use.

Correct Answer: D

Rationale: Rationale: Atropine is a muscarinic antagonist that blocks the action of acetylcholine at muscarinic receptors. Salivary glands are innervated by the parasympathetic nervous system, which uses acetylcholine as its neurotransmitter to stimulate salivary secretion. By blocking the action of acetylcholine with atropine, the secretion of saliva is decreased, making the correct answer D. A) Adrenal medulla is not directly affected by atropine. Atropine does not have a significant impact on adrenal medullary function as it primarily acts on muscarinic receptors in the peripheral nervous system. B) The kidney is not a target organ affected by atropine. Atropine's primary effects are on muscarinic receptors in various organs innervated by the parasympathetic nervous system, but it does not directly impact renal function. C) Pilomotor muscles are also not a primary target of atropine. Atropine's main action is on muscarinic receptors in organs such as the heart, smooth muscles, and exocrine glands, rather than on muscles responsible for piloerection. Educational context: Understanding the pharmacology of atropine is crucial in healthcare settings where its use is common, such as in anesthesia to reduce secretions or in the treatment of bradycardia. Knowledge of atropine's mechanism of action helps healthcare professionals anticipate its effects and side effects, ensuring safe and effective patient care. This question highlights the importance of understanding how drugs like atropine work on specific target organs and the significance of their pharmacological actions in clinical practice.

Correct Answer: A

Rationale: In this scenario, the most likely explanation for the patient's inability to wean off the ventilator postoperatively is diaphragm paralysis. Succinylcholine, a depolarizing neuromuscular blocking agent used during anesthesia, can lead to prolonged paralysis of the diaphragm, resulting in respiratory muscle weakness and the need for continued ventilatory support. This effect is particularly significant in elderly patients due to age-related changes in neuromuscular function. Hypokalemia (Option B) could potentially affect muscle function, but it is not the most likely cause in this case. Hyponatremia (Option C) and hypocalcemia (Option D) may cause various complications but are not directly related to the patient's prolonged ventilator dependency post-surgery. From an educational perspective, understanding the pharmacological effects of drugs used during anesthesia is crucial for healthcare providers managing postoperative complications. Recognizing the potential risks and complications associated with specific medications can help in anticipating and managing adverse outcomes in vulnerable patient populations, such as the elderly. This case underscores the importance of considering drug-induced complications in critically ill patients and highlights the significance of monitoring respiratory function in postoperative care.

Correct Answer: B

Rationale: In this case, the most appropriate answer is B) Tamsulosin. Tamsulosin is a selective alpha-1 adrenergic receptor antagonist that acts specifically on the smooth muscle of the prostate and bladder neck, leading to relaxation of these muscles and improving urinary flow in patients with benign prostatic hyperplasia (BPH). Alfuzosin (option A) is also an alpha-1 adrenergic receptor antagonist used in BPH, but tamsulosin has shown to have a more favorable side effect profile and is generally better tolerated, especially in elderly patients. Phenoxybenzamine (option C) and phentolamine (option D) are non-selective alpha-adrenergic receptor antagonists, and their use in BPH is limited due to their potential for significant side effects like hypotension and reflex tachycardia. Educationally, understanding the mechanism of action of different alpha-adrenergic receptor antagonists and their selectivity can aid in choosing the most appropriate medication for specific patient populations, like in this case of an elderly patient with hypertension and BPH. It is crucial to weigh the efficacy and safety profiles of medications to provide optimal care for patients with complex medical conditions like the one presented in the scenario.