Give the definition for a therapeutical dose:

Correct Answer: C

Rationale: The therapeutical dose is the amount of a substance required to produce the desired effect in most patients. This is because it aims to provide optimal benefits with minimal side effects. Choice A is incorrect as it refers to a subtherapeutic dose. Choice B is incorrect as it describes a toxic dose. Choice D is incorrect as it does not accurately define a therapeutical dose.

Correct Answer: B

Rationale: The correct answer is B: Mydriasis. Cholinesterase inhibitors cause excessive stimulation of the parasympathetic nervous system, leading to symptoms such as salivation, sweating, bronchial constriction, and GI symptoms. Mydriasis, or pupil dilation, is not a typical initial symptom of cholinesterase inhibitor intoxication. Pupil constriction (miosis) is actually more common due to increased parasympathetic activity. Therefore, mydriasis does not fit the profile of initial symptoms seen in cholinesterase inhibitor intoxication.

Correct Answer: A

Rationale: The correct answer is A because depolarizing agents, like succinylcholine, directly open the nicotinic receptor channel causing prolonged depolarization. Choice B is correct, as depolarizing agents react with the nicotinic receptor to cause depolarization. Choice C is incorrect because desensitization and flaccid paralysis are associated with non-depolarizing agents. Choice D is incorrect because cholinesterase inhibitors can reverse non-depolarizing blockade by preventing acetylcholine breakdown.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Xylometazoline is an alpha-2 adrenergic receptor agonist. 2. Activation of alpha-2 receptors centrally leads to reduced sympathetic outflow and vasodilation. 3. Vasodilation can cause hypotension, similar to clonidine's mechanism. 4. Methoxamine (A) and phenylephrine (B) are alpha-1 agonists, causing vasoconstriction. 5. Isoproterenol (D) is a non-selective beta agonist, leading to increased heart rate and contractility, potentially causing hypertension.

Correct Answer: C

Rationale: The correct answer is C: Inhibition of glycogenolysis. 1. Beta-receptor antagonists inhibit the action of catecholamines (epinephrine, norepinephrine). 2. Catecholamines normally stimulate beta-receptors, promoting glycogenolysis. 3. Therefore, beta-blockers block this stimulation, leading to the inhibition of glycogenolysis. Summary: A: Stimulation of lipolysis - Incorrect. Beta-blockers do not stimulate lipolysis. B: Stimulation of gluconeogenesis - Incorrect. Beta-blockers do not stimulate gluconeogenesis. D: Stimulation of insulin secretion - Incorrect. Beta-blockers actually inhibit insulin secretion.