A 10-year-old boy is diagnosed with Attention Deficit/Attention Deficit-Hyperactivity disorder (ADD/ADHD). Which of the following drugs is most likely to prove effective for relieving the boy’s main symptoms?

Correct Answer: B

Rationale: The correct answer is B: Amphetamine. Amphetamine is a stimulant commonly used to treat symptoms of ADHD as it helps improve focus, impulse control, and hyperactivity. It works by increasing the levels of certain neurotransmitters in the brain. Dobutamine (A) is a different type of stimulant used for heart conditions. Pancuronium (C) is a muscle relaxant used during surgery, and Prazosin (D) is an alpha-blocker used for high blood pressure and PTSD nightmares. Therefore, Amphetamine is the most likely drug to be effective for relieving the boy's main symptoms of ADHD.

Correct Answer: D

Rationale: The correct answer is D because parathion is not a parasympathomimetic drug; it is an organophosphorus insecticide. Physostigmine (A), Neostigmine (B), and Edrophonium (C) are all parasympathomimetics used for their respective therapeutic purposes. Physostigmine is used in glaucoma to reduce intraocular pressure, Neostigmine is used to treat postoperative urinary retention by improving bladder emptying, and Edrophonium is used in the diagnosis of myasthenia gravis by temporarily improving muscle strength. In contrast, parathion is not a medication but a toxic substance used in insecticides, and it does not have any therapeutic use as a parasympathomimetic drug.

Correct Answer: D

Rationale: Correct Answer: D. Increases blood flow to the injection area. Rationale: 1. Adrenaline is a vasoconstrictor that reduces blood flow in the injection area. 2. By constricting blood vessels, adrenaline limits the absorption of the local anesthetic, leading to prolonged local action. 3. Adrenaline also helps in reducing the systemic toxicity of the local anesthetic by limiting its absorption. 4. Therefore, the correct answer is D as adrenaline does not increase blood flow to the injection area.

Correct Answer: A

Rationale: The correct answer is A: Excessive salivation. Atropine is an anticholinergic medication that blocks the action of acetylcholine, leading to decreased secretions including saliva. Excessive salivation is not an adverse effect but rather a therapeutic effect of atropine. Choices B, C, and D are incorrect because retention of urine, sinus tachycardia, and constipation are known adverse effects of atropine due to its anticholinergic properties.

Correct Answer: D

Rationale: The correct answer is D: Tachycardia. Anticholinergic medications block the action of acetylcholine, leading to increased heart rate (tachycardia) by inhibiting the parasympathetic nervous system. Excessive salivation (choice A) is a cholinergic effect, not anticholinergic. Bradycardia (choice B) is not consistent with anticholinergic side effects. Diarrhea and colic (choice C) are more commonly associated with cholinergic, not anticholinergic, effects.