N-acetylcysteine is beneficial in acute paracetamol poisoning because

Correct Answer: D

Rationale: N-acetylcysteine restores glutathione levels, preventing hepatotoxicity from toxic paracetamol metabolites.

Correct Answer: C

Rationale: Many general anesthetics inhibit glutamate (excitatory neurotransmitter) to produce sedation and anesthesia.

Correct Answer: B

Rationale: Epinephrine causes vasoconstriction, reducing systemic absorption and prolonging the duration of the local anesthetic effect.

Correct Answer: D

Rationale: The correct answer is D: A boy with an inability to complete tasks. This is important because it is a key symptom of attention-deficit/hyperactivity disorder (ADHD). Observing this behavior can help confirm the diagnosis and guide appropriate interventions. Explanation: 1. Inability to complete tasks is a common symptom of ADHD, indicating difficulties with focus and organization. 2. Lethargy (Choice A) is not a typical symptom of ADHD, which is characterized by hyperactivity and impulsivity. 3. Lack of impulsivity (Choice B) contradicts the typical presentation of impulsivity seen in ADHD. 4. Smooth coordination (Choice C) is not a primary symptom of ADHD and does not directly relate to the disorder's diagnosis. In summary, observing a boy with an inability to complete tasks is crucial for evaluating ADHD, as it aligns with the disorder's core symptoms, unlike the other choices.

Correct Answer: A

Rationale: Carbimazole (choice A) and Propylthiouracil (choice D) treat hyperthyroidism by inhibiting thyroid hormone synthesis, Propranolol (choice C) manages symptoms. Carbamazepine (choice B), an anticonvulsant, is unrelated, making it the exception. This clarifies antithyroid therapy.