Indicate the drug, which has greater potency of the local anesthetic action:

Correct Answer: B

Rationale: The correct answer is B: Bupivacaine. Bupivacaine has a greater potency of local anesthetic action due to its higher lipid solubility and protein binding, leading to a slower onset and longer duration of action compared to other choices. Lidocaine (A) has a faster onset but shorter duration. Procaine (C) has a lower potency due to its lower lipid solubility. Mepivacaine (D) has a similar potency to lidocaine but with a shorter duration of action.

Correct Answer: B

Rationale: The correct answer is B: Pralidoxime. Pralidoxime is an antidote used to regenerate cholinesterase inhibited by organophosphate poisoning, which affects skeletal muscle neuromuscular junctions. It works by reactivating the cholinesterase enzyme, restoring its function. Succinylcholine (A) is a muscle relaxant, not an agent for regenerating cholinesterase. Pirenzepine (C) is a muscarinic receptor antagonist used for gastric ulcers. Propiverine (D) is a bladder antimuscarinic. So, the most effective agent for regenerating cholinesterase at the neuromuscular junction is Pralidoxime.

Correct Answer: D

Rationale: The correct answer is D: Beta 2 receptor. Bronchial smooth muscle relaxation is mainly mediated by Beta 2 adrenergic receptors when activated by agonists like salbutamol. These receptors stimulate adenylate cyclase leading to increased cAMP levels, which in turn promotes muscle relaxation. Alpha 1 receptors (Choice A) and Alpha 2 receptors (Choice B) are associated with vasoconstriction and decreased sympathetic outflow, respectively, not bronchial smooth muscle relaxation. Beta 1 receptors (Choice C) are primarily found in the heart and play a role in cardiac function, not bronchial smooth muscle relaxation.

Correct Answer: A

Rationale: Rationale: Labetalol is a reversible nonselective alpha-beta antagonist. It blocks both alpha and beta receptors. It is reversible due to its competitive binding, making it effective in managing hypertension. Phentolamine is an alpha blocker, not affecting beta receptors. Metoprolol and Propranolol are both beta blockers, targeting beta receptors only, making them selective and not reversible nonselective alpha-beta antagonists.

Correct Answer: C

Rationale: The correct answer is C: Phenobarbital. Phenobarbital is a long-acting barbiturate that can lead to cumulative and residual effects due to its long half-life and potential for drug accumulation in the body over time. This can result in prolonged sedative effects and increased risk of side effects. Zolpidem (A), Temazepam (B), and Triazolam (D) are shorter-acting hypnotic drugs with less potential for cumulative and residual effects compared to Phenobarbital.