All of the following drugs are parasympatholytic drugs EXCEPT:

Correct Answer: C

Rationale: The correct answer is C: Pilocarpine. Parasympatholytic drugs inhibit the parasympathetic nervous system. Pilocarpine, on the other hand, is a parasympathomimetic drug that stimulates the parasympathetic nervous system. Hyoscine, Atropine, and Ipratropium are all parasympatholytic drugs that block the effects of the parasympathetic nervous system. Therefore, pilocarpine is the exception in this list.

Correct Answer: D

Rationale: The correct answer is D: Beta-adrenergic antagonists. Beta-blockers can mask the typical signs and symptoms of hypoglycemia such as tremors, palpitations, and sweating by inhibiting the adrenergic response to low blood sugar levels. Other choices (A, B, C) are incorrect as they do not have the same mechanism of action in masking hypoglycemic reactions in diabetic patients.

Correct Answer: C

Rationale: The correct answer is C: Phenylephrine. Phenylephrine is a sympathomimetic drug that stimulates the sympathetic nervous system, leading to vasoconstriction and increased heart rate. In contrast, choices A, B, and D all work to depress sympathetic activity by different mechanisms. Clonidine is an alpha-2 adrenergic agonist that decreases sympathetic outflow. Reserpine inhibits the storage of norepinephrine, leading to decreased sympathetic activity. Labetalol is a non-selective beta blocker that blocks beta-adrenergic receptors, reducing sympathetic effects. Therefore, Phenylephrine is the only drug among the options that does not depress sympathetic activity.

Correct Answer: C

Rationale: Cocaine blocks the reuptake of noradrenaline from adrenergic nerves, leading to excessive stimulation of adrenergic receptors. This causes increased blood pressure, which can result in a hypertensive crisis or stroke. Additionally, the vasoconstrictive effects of excess noradrenaline can lead to tissue damage in the nose when cocaine is inhaled frequently. Choices A and B are incorrect because cocaine does not directly block alpha adrenergic or muscarinic receptors. Choice D is incorrect because cocaine does not deplete norepinephrine from adrenergic nerve endings but rather increases its concentration by blocking reuptake.

Correct Answer: A

Rationale: The correct answer is A: "Don't stop taking this medication without a doctor's advice first." Abruptly stopping a β-blocker can lead to severe adverse reactions like rebound hypertension, angina exacerbation, or arrhythmias due to sudden withdrawal. This instruction is crucial to prevent these potentially dangerous consequences. Explanation for why other choices are incorrect: B: β-blockers are not known to commonly cause urinary frequency, so this warning is unnecessary. C: Blurred vision is not a common side effect of β-blockers, so this warning is irrelevant. D: While constipation can be a side effect of some medications, it is not a prominent side effect of β-blockers, so this advice is not essential for patients taking β-blockers.