A 66-year-old woman who has smoked two packs of cigarettes per day for 50 years has chronic bronchitis. She has tried to quit five times in the past but felt she could not go long without a cigarette. The nicotine in her cigarettes stimulates many cells in her body by binding certain receptors. Which of the following drugs blocks nicotinic receptors?

Correct Answer: C

Rationale: In this scenario, the correct answer is C) Hexamethonium, a ganglionic blocking agent that acts by blocking nicotinic receptors. In the context of a chronic smoker with bronchitis, blocking nicotinic receptors can help reduce the addictive effects of nicotine and potentially aid in smoking cessation. Atropine (A) is a muscarinic antagonist and would not block nicotinic receptors. Bethanechol (B) is a cholinergic agonist used to stimulate bladder contractions and would not block nicotinic receptors. Metoprolol (D) is a beta-blocker and would not act on nicotinic receptors. Educationally, understanding the specific mechanisms of action of drugs is crucial in pharmacology to ensure appropriate drug selection for different conditions. In this case, knowing that Hexamethonium blocks nicotinic receptors can help in managing nicotine addiction and its effects on the body. This knowledge is essential for healthcare professionals in making informed decisions regarding drug therapy for patients.

Correct Answer: B

Rationale: In this scenario, the correct answer is B) Biotransformed in the liver and excreted in urine. Methadone is a synthetic opioid used in medication-assisted treatment for opioid dependence. It undergoes extensive hepatic metabolism by various cytochrome P450 enzymes in the liver, primarily CYP3A4, leading to the formation of inactive metabolites that are excreted in the urine. This metabolic pathway is crucial for understanding the pharmacokinetics of methadone. Option A is incorrect because methadone is not best absorbed intravenously. It has good oral bioavailability, making oral administration the preferred route for maintenance therapy. Option C is incorrect as methadone is not particularly lipophilic, which would lead to tissue accumulation. Methadone's lipophilicity is moderate, contributing to its long half-life and duration of action. Option D is also incorrect as methadone metabolism involves multiple cytochrome enzymes, not a single one. Understanding the pharmacology of methadone is essential for healthcare providers involved in managing opioid use disorder. Knowledge of its metabolism, excretion, pharmacokinetics, and potential drug interactions is crucial for safe and effective treatment. This question highlights the importance of pharmacological principles in the context of substance use disorders and medication-assisted therapies.

Correct Answer: B

Rationale: A competitive benzodiazepine receptor antagonist binds to the GABAa receptor's benzodiazepine site, preventing agonists like diazepam from exerting effects, without activating the receptor itself. Flumazenil is this antagonist, used to reverse benzodiazepine overdose (e.g., reversing sedation or respiratory depression) by competitively displacing agonists. Naloxone (choice A) is an opioid antagonist, targeting mu receptors to reverse opioid overdose, not benzodiazepine-related. Flurazepam (choice C) is a benzodiazepine agonist, promoting GABA effects, not blocking them. Disulfuram (choice D, likely misspelled) inhibits aldehyde dehydrogenase for alcoholism treatment, unrelated to benzodiazepine receptors. Flumazenil's specificity and competitive nature make it the correct choice. This question emphasizes antidote recognition, critical in emergency settings to counteract CNS depression, distinguishing it from other reversal agents like Naloxone.

Correct Answer: D

Rationale: Aspirin (acetylsalicylic acid) is used in acute rheumatic fever (choice D) for its anti-inflammatory and analgesic effects, reducing joint pain and inflammation in this autoimmune condition post-streptococcal infection. Vertigo (choice A) isn't an inflammatory condition aspirin targets. Peptic ulcer (choice B) is a contraindication, as aspirin exacerbates ulceration via COX-1 inhibition. Acute bronchial asthma (choice C) may worsen with aspirin due to leukotriene overproduction in sensitive patients. Acute rheumatic fever aligns with aspirin's anti-inflammatory utility, making it the correct therapeutic indication.

Correct Answer: C

Rationale: Fluoxetine (choice C), an SSRI, treats depression by selectively inhibiting serotonin reuptake, increasing synaptic levels. Imipramine (choice A) and Amitriptyline (choice B), tricyclic antidepressants, block multiple transmitters, not just serotonin. Maprotiline (choice D), a tetracyclic, primarily affects norepinephrine. Fluoxetine's specificity reduces side effects, making it a cornerstone in depression therapy.