An 18-year-old woman presents to clinic because of difficulty with school. She recently started college and is living on her own for the first time. She is constantly preoccupied with wondering if the door is locked. She checks the lock at least 20 times before she is able to leave her apartment. This often makes her late for class. She had been on selective serotonin reuptake inhibitors in the past, but they are ineffective. What is the most appropriate treatment for this patient?

Correct Answer: B

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

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: A

Rationale: Loperamide (choice A), a mu-opioid agonist, acts peripherally on GIT receptors, reducing motility and treating diarrhea without significant CNS effects due to poor blood-brain barrier penetration. Pentazocine (choice B), a mixed agonist-antagonist, and Heroin (choice C), a full agonist, primarily affect the CNS, not selectively the GIT. Neostigmine (choice D), a cholinesterase inhibitor, increases motility, opposing morphine's effect. Loperamide's selective GIT action makes it ideal for diarrhea, distinguishing it from systemic opioids.

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.