Constipation is caused by all of the following drugs EXCEPT :
**Core Concept**
Constipation is a complex condition involving decreased bowel motility, increased water absorption, or a combination of both. It can be caused by various factors, including medications that affect the gastrointestinal (GI) system.
**Why the Correct Answer is Right**
The correct answer is likely an anticholinergic medication, such as Olanzapine (Option A) or Tricyclic antidepressants (Option B). Anticholinergic drugs block the action of acetylcholine, a neurotransmitter that stimulates smooth muscle contraction in the GI tract, leading to decreased bowel motility and constipation.
**Why Each Wrong Option is Incorrect**
**Option A:** Olanzapine is a second-generation antipsychotic with significant anticholinergic effects, which can cause constipation as a side effect.
**Option B:** Tricyclic antidepressants also have anticholinergic properties, contributing to constipation.
**Option C:** This option is missing, but you can assume it's an incorrect answer.
**Clinical Pearl / High-Yield Fact**
Anticholinergic medications can also cause other side effects like dry mouth, blurred vision, and urinary retention due to their effects on smooth muscle and glandular tissues.
**Correct Answer:** B. Tricyclic antidepressants