Which of the following opioid analgesics is a strong mu receptor agonist?

Correct Answer: B

Rationale: The correct answer is B: Morphine. Morphine is a strong mu receptor agonist because it binds to and activates the mu opioid receptors in the central nervous system, leading to potent analgesic effects. Naloxone (A) is an opioid receptor antagonist, not an agonist. Pentazocine (C) is a mixed opioid receptor agonist/antagonist. Buprenorphine (D) is a partial mu receptor agonist with mixed antagonist properties. Therefore, the other choices do not fit the criteria of being a strong mu receptor agonist like morphine.

Correct Answer: C

Rationale: The correct answer is C because antidepressants primarily work by blocking the reuptake pumps of serotonin or norepinephrine, increasing the levels of these neurotransmitters in the synaptic cleft. This leads to enhanced neurotransmission and improved mood regulation. Choices A, B, and D are incorrect as they do not accurately describe the primary mechanism of action of antidepressants. Stabilization of dopamine and beta-adrenergic receptors (A) is not the main mechanism, inhibition of storage of serotonin and epinephrine (B) is not how antidepressants work, and stimulation of alfa2-norepinephrine receptors (D) is not the primary mechanism for antidepressant effects.

Correct Answer: A

Rationale: The correct answer is A: Meridil. Meridil is a CNS stimulant that is a piperidine derivative. Piperidine is a chemical structure that is present in the drug Meridil, making it the correct choice. Amphetamine (B) is not a piperidine derivative; it belongs to the phenethylamine class. Caffeine (C) is a xanthine derivative. Sydnophen (D) is not a piperidine derivative but a sympathomimetic amine. Therefore, based on the chemical structure and classification, Meridil is the only option that fits the criteria of being a piperidine derivative.

Correct Answer: B

Rationale: Step 1: Flumazenil is a benzodiazepine receptor antagonist used to reverse benzodiazepine overdose. Step 2: Given intravenously, it acts rapidly to competitively inhibit the effects of benzodiazepines. Step 3: Flumazenil has a short half-life of about 1 hour, resulting in a rapid onset but short duration of action. Step 4: Therefore, choice B is correct as it accurately describes the pharmacokinetics of flumazenil. Summary: Choices A, C, and D are incorrect because flumazenil does not have an intermediate onset and duration of action of about 2 hours, an effect lasting 3-5 hours, or a duration of action longer than 6 hours.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Thiopental, etomidate, and propofol are commonly used intravenous agents for induction of anesthesia. They provide a faster onset and rate of recovery compared to inhaled anesthetics. Additionally, these agents do not provide conscious sedation but rather induce a state of unconsciousness for surgical procedures. Therefore, the correct answer is D as it encompasses all the unique characteristics of intravenous anesthetics compared to inhaled anesthetics.