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.