Effects of morphine on the GIT include all of the following EXCEPT:

Correct Answer: A

Rationale: Morphine affects the gastrointestinal tract (GIT) via mu-opioid receptors. Decreased gastric motility slows emptying, contributing to nausea and constipation. Decreased biliary, pancreatic, and intestinal secretions result from opioid-induced smooth muscle relaxation and reduced exocrine activity. Increased intrabiliary pressure stems from sphincter of Oddi constriction, potentially causing biliary colic. However, morphine decreases, not increases, propulsive peristaltic waves in the colon (choice A), leading to constipation by enhancing non-propulsive contractions and reducing motility. This mischaracterization makes it the exception. Recognizing these effects is critical for managing opioid side effects, particularly constipation, a common patient complaint requiring adjunctive therapy.

Correct Answer: D

Rationale: Methylxanthines (e.g., caffeine, theophylline) stimulate the CNS (choice A), dilate most vessels except cerebral (choice B), and relax bronchi (choice C), aiding asthma. They aren't contraindicated in gout (choice D); they don't affect uric acid metabolism like allopurinol does. This incorrect statement highlights their respiratory and CNS utility, not gout relevance.

Correct Answer: B

Rationale: Benzodiazepines reduce anxiety (choice A), control seizures (choice C), and relax muscles (choice D) via GABAa enhancement. They lack antipsychotic action (choice B), which requires dopamine D2 blockade (e.g., haloperidol), not GABA modulation. This exception differentiates anxiolytics from antipsychotics in CNS therapy.

Correct Answer: B

Rationale: Chlorpromazine, a typical antipsychotic, blocks D2 receptors (choice B) in the mesolimbic pathway, reducing positive schizophrenia symptoms. D1 blockade (choice A) is less critical, adrenergic (choice C) and opiate (choice D) blockade are side effects, not primary. D2 antagonism is its core mechanism.

Correct Answer: A

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.