A child overdoses on a drug that affects both the autonomic and somatic nervous systems. As blood level of the drug rises, he experiences hypertension and tachycardia, accompanied by skeletal muscle tremor. Further elevations of the drug cause all the expected signs and symptoms of autonomic ganglionic blockade, plus weakness and eventual paralysis of skeletal muscle. Which of the following drugs did the child most likely ingest?

Correct Answer: B

Rationale: The correct answer is B: Nicotine. Nicotine affects both the autonomic and somatic nervous systems. Initially, the child experiences hypertension, tachycardia, and skeletal muscle tremor due to stimulation of both systems. As the blood level rises, autonomic ganglionic blockade occurs, leading to weakness and paralysis. Bethanechol (A) is a cholinergic agonist, unlikely to cause these symptoms. Pilocarpine (C) is also a cholinergic agonist but does not affect the somatic nervous system. Scopolamine (D) is an anticholinergic drug, which would not cause the symptoms described.

Correct Answer: C

Rationale: The correct answer is C: Peripheral vascular disease. Non-selective β-blockers can cause vasoconstriction and exacerbate peripheral vascular disease by reducing blood flow to the extremities. This can lead to worsening symptoms and potential tissue damage. Choices A, B, and D are incorrect because non-selective β-blockers are commonly used in angina of effort, systemic hypertension, and thyrotoxicosis, respectively, to decrease heart rate and blood pressure.

Correct Answer: B

Rationale: The correct answer is B: Ergotamine. Ergotamine is a vasoconstrictor that helps alleviate migraine symptoms by constricting blood vessels in the brain. It is commonly used to treat acute migraine attacks. Prazosin (A) is an alpha-blocker used for hypertension, not migraines. Propranolol (C) is a beta-blocker used for migraine prevention, not acute treatment. Amphetamine (D) is a stimulant used for ADHD, not migraine treatment. Ergotamine's vasoconstrictive properties make it effective for treating acute migraines.

Correct Answer: A

Rationale: The correct answer is A: Pilocarpine. Pilocarpine is a direct-acting parasympathomimetic that readily passes the blood-brain barrier due to its small molecular size. It is commonly used in the treatment of glaucoma by constricting the pupil and increasing the outflow of aqueous humor. Carbachol and Bethanechol are also parasympathomimetics, but they do not readily cross the blood-brain barrier. Methacholine is a muscarinic receptor agonist, not commonly used in the treatment of glaucoma. Therefore, the most suitable choice that meets the criteria provided in the question is pilocarpine.

Correct Answer: D

Rationale: The correct answer is D: They increase renin activity. Beta blockers block beta-adrenergic receptors, leading to decreased renin secretion and ultimately decreased renin activity. This results in reduced renin-angiotensin-aldosterone system activation, leading to decreased blood pressure. Choices A, B, and C are incorrect because beta blockers are known to decrease blood pressure, propranolol is extensively metabolized in the liver, and atenolol is eliminated mainly unchanged in urine.