A 34-year-old woman with chronic irritable bowel syndrome with predominance of diarrhea and left lower quadrant pain begins smoking in response to the numerous stresses in her personal and professional life. She smokes one pack per day. She presents to her primary care physician for treatment of her irritable bowel syndrome. The physician expects a change in which of the following symptoms of her irritable bowel syndrome?

Correct Answer: A

Rationale: Nicotine can exacerbate diarrhea in patients with irritable bowel syndrome, particularly those with diarrhea-predominant IBS.

Correct Answer: D

Rationale: Buspirone (choice A), Alprazolam (choice B), and Baclofen (choice C) are correctly paired (anxiolytic, some antidepressant effect, less sedative muscle relaxant). Oxazepam (choice D), a benzodiazepine, isn't a TCA, making it the incorrect pair. This tests drug classification.

Correct Answer: D

Rationale: Levodopa does not cause livedo reticularis (a net-like skin discoloration), but it can cause other side effects such as nausea, dizziness, and dyskinesia.

Correct Answer: A

Rationale: Morphine has very low protein binding compared to other opioids allowing it to have more free drug available in circulation.

Correct Answer: C

Rationale: Lithium reaches its peak serum levels typically within 2 to 4 hours after oral administration.