Which of the following local anesthetics is more likely to cause allergic reactions?

Correct Answer: C

Rationale: The correct answer is C: Procaine. Procaine is more likely to cause allergic reactions due to its structural similarity to PABA, a common allergen. It can trigger allergic responses in individuals sensitive to PABA. Lidocaine, Bupivacaine, and Ropivacaine are less likely to cause allergic reactions as they have different chemical structures and mechanisms of action. Allergy to these drugs is rare compared to procaine.

Correct Answer: C

Rationale: The correct answer is C: Interaction with adrenoreceptors. Indirect action involves affecting catecholamines' release, reuptake, or displacement, not direct interaction with adrenoreceptors. A: Displacement of stored catecholamines is correct as it refers to causing the release of stored catecholamines. B: Inhibition of reuptake is correct as it refers to preventing the reuptake of catecholamines. D: Inhibition of release of endogenous catecholamines is correct as it refers to stopping the release of catecholamines from nerve endings.

Correct Answer: A

Rationale: The correct answer is A: Formoterol. It is a long-acting beta2-adrenergic agonist used in bronchial asthma therapy to dilate airways by relaxing smooth muscles. Norepinephrine (B) is a vasopressor, not used in asthma. Methoxamine (C) is an alpha1-adrenergic agonist, not indicated for asthma. Dobutamine (D) is a beta1-adrenergic agonist mainly used in heart failure, not asthma. Formoterol's mechanism of action aligns with the therapeutic goal of bronchial asthma treatment, making it the correct choice.

Correct Answer: C

Rationale: The correct answer is C: Pheochromocytoma. Beta-receptor blocking drugs are contraindicated in pheochromocytoma because they can potentially worsen hypertension due to unopposed alpha-adrenergic effects. Choice A is correct as beta-blockers are commonly used in hypertension, ischemic heart disease, and cardiac arrhythmias. Choice B is incorrect as beta-blockers are used in the treatment of glaucoma to reduce intraocular pressure. Choice D is incorrect as beta-blockers are used to manage symptoms of hyperthyroidism such as tachycardia and tremors.

Correct Answer: D

Rationale: The correct answer is D because all of the antiseizure drugs listed (Lamotrigine, Carbamazepin, Phenytoin) produce voltage-dependent inactivation of sodium channels. This mechanism helps to control neuronal excitability and prevent seizure activity. Lamotrigine inhibits voltage-gated sodium channels by stabilizing their inactive state. Carbamazepin and Phenytoin also act by blocking sodium channels in a voltage-dependent manner. Therefore, all of these drugs are effective in preventing seizures by modulating sodium channel function. The other choices (A, B, C) are incorrect because they individually target sodium channels through voltage-dependent inactivation, distinguishing them from other antiseizure drugs that act through different mechanisms.