Bethanechol has all of the following properties EXCEPT:

Correct Answer: D

Rationale: The correct answer is D because Bethanechol is a muscarinic agonist, meaning it specifically targets muscarinic receptors, not nicotinic receptors. Nicotinic receptors are primarily found at neuromuscular junctions and act on skeletal muscle. Bethanechol's main action is on smooth muscle, particularly in the gastrointestinal and urinary tracts. It is used to stimulate bladder contractions in cases of urinary retention and to treat abdominal distention. Choice A is incorrect because bethanechol is not resistant to hydrolysis, and choice B is incorrect because it is purely muscarinic in action, not exerting nicotinic effects.

Correct Answer: B

Rationale: The correct answer is B: Terbutaline. Terbutaline is a selective beta-2 adrenergic agonist that causes bronchodilation by acting on beta-2 receptors in the lungs without significant cardiac stimulation. Isoprenaline (A) is a non-selective beta agonist that can cause significant cardiac stimulation. Xylometazoline (C) is a nasal decongestant that acts on alpha-adrenergic receptors and does not cause bronchodilation. Methoxamine (D) is an alpha-1 adrenergic agonist that can actually cause bronchoconstriction and does not cause bronchodilation.

Correct Answer: A

Rationale: Rationale: A: Adrenoreceptor antagonists work by reversible or irreversible interaction with adrenoreceptors, blocking the action of catecholamines. This directly affects the sympathetic nervous system. B: Depletion of catecholamines is not the primary mechanism of action of adrenoreceptor antagonists. C: Blockade of amine reuptake pumps is not the primary mechanism of action of adrenoreceptor antagonists. D: Nonselective MAO inhibition is not the mechanism of action of adrenoreceptor antagonists.

Correct Answer: A

Rationale: Step-by-step rationale for choice A being correct: Hepatic microsomal drug-metabolizing enzyme induction increases the metabolism of drugs like barbiturates. This leads to decreased drug levels, resulting in tolerance - requiring higher doses for the same effect. Choices B, C, and D are incorrect because cumulative effects refer to increased drug levels due to impaired metabolism, physical dependence is related to behavioral aspects, and hangover effects are due to drug toxicity or residual effects, not enzyme induction.

Correct Answer: A

Rationale: The correct answer is A. Carbamazepine is an antiepileptic drug known to cause dose-related adverse effects such as diplopia (double vision), ataxia (lack of coordination), and nausea. Diplopia and ataxia are common neurological side effects, while nausea is a gastrointestinal side effect. This is due to the drug's mechanism of action on sodium channels in the nervous system. Choices B, C, and D are incorrect. Gingival hyperplasia and hirsutism are not common adverse effects of carbamazepine. Sedation and dependence are more associated with benzodiazepines, and hemeralopia and myasthenic syndrome are not typically linked to carbamazepine use.