Indicate the local anesthetic, which is a toluidine derivative:

Correct Answer: A

Rationale: The correct answer is A: Lidocaine. Lidocaine is a toluidine derivative due to its chemical structure containing a toluidine group. The toluidine derivative refers to the presence of a methyl group on the amino nitrogen atom, as seen in Lidocaine. Bupivacaine (B) is an amino amide local anesthetic, not a toluidine derivative. Prilocaine (C) is an amino amide local anesthetic like Bupivacaine. Procaine (D) is an ester local anesthetic, not a toluidine derivative. Hence, the correct choice is A (Lidocaine) as it meets the criteria of being a toluidine derivative.

Correct Answer: C

Rationale: The correct answer is C: Bronchial asthma. Antimuscarinic drugs can worsen bronchial asthma due to their potential to cause bronchoconstriction. Glaucoma (A), myasthenia (B), and paralytic ileus/urinary bladder atony (D) are contraindications for antimuscarinic drugs due to their exacerbation of symptoms in these conditions. Glaucoma can worsen due to increased intraocular pressure, myasthenia can lead to muscle weakness, and antimuscarinic drugs can further inhibit bowel and bladder function in paralytic ileus and urinary bladder atony.

Correct Answer: D

Rationale: Beta2 receptor stimulation primarily leads to vasodilation, bronchodilation, and relaxation of smooth muscles in non-cardiac tissues. It does not cause tachycardia, which is primarily mediated by Beta1 receptor stimulation. Therefore, option D is the correct answer. Option A is incorrect because Beta2 stimulation does not stimulate renin secretion. Option B is incorrect as Beta2 stimulation increases potassium concentration in plasma. Option C is incorrect as Beta2 stimulation causes relaxation of bladder and uterus muscles.

Correct Answer: B

Rationale: The correct answer is B: Stimulation of responses to serotonin. Phentolamine is an alpha-adrenergic blocker, causing vasodilation and reducing peripheral resistance (A). It can lead to tachycardia (C) due to its vasodilatory effects. Phentolamine does not stimulate muscarinic H1 and H2 histamine receptors (D). Serotonin receptors are not affected by phentolamine, making choice B the correct answer.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Barbiturates are known to increase the metabolism of various drugs, including anticoagulants, digitalis compounds, and glucocorticoids. This is because barbiturates induce liver enzymes responsible for drug metabolism, leading to faster clearance of these medications from the body. Therefore, the correct answer is D as barbiturates can affect the metabolism of all the mentioned drug classes. Choices A, B, and C are incorrect as barbiturates do not selectively increase the metabolism of only one of these drug classes, but rather have a broad impact on drug metabolism.