Atropine when used as a pre-medication causes all of the following symptoms except –
**Core Concept**
Atropine, a muscarinic receptor antagonist, is used as a pre-medication to reduce salivation, bronchial secretions, and other parasympathetic effects during anesthesia. This is due to its ability to block the action of acetylcholine at muscarinic receptors in the central and peripheral nervous system.
**Why the Correct Answer is Right**
Atropine's anticholinergic effects lead to the inhibition of the parasympathetic nervous system, resulting in decreased salivation, bronchial secretions, and increased heart rate. The reduction in parasympathetic tone also causes dilation of the pupils, decreased sweating, and increased intraocular pressure. Atropine's use as a pre-medication is aimed at reducing these effects to prevent complications during anesthesia.
**Why Each Wrong Option is Incorrect**
**Option A:** Not provided, skipping to next option.
**Option B:** Incorrect because atropine actually increases heart rate, not decreases it.
**Option C:** Incorrect because atropine causes mydriasis (pupil dilation), not miosis (pupil constriction).
**Option D:** Incorrect because atropine can cause urinary retention, not increased urination.
**Clinical Pearl / High-Yield Fact**
Remember that atropine can cause a range of anticholinergic side effects, including dry mouth, blurred vision, and urinary retention. Be aware of these potential complications when using atropine as a pre-medication.
**Correct Answer: C. Miosis.**