Anticholinergic side effect is:
**Core Concept**
Anticholinergic side effects are a result of the blockade of acetylcholine receptors in the central and peripheral nervous system. This leads to a decrease in the parasympathetic tone, resulting in various side effects.
**Why the Correct Answer is Right**
The correct answer is a manifestation of the anticholinergic blockade, which affects the muscarinic receptors in the eye. The resulting mydriasis (pupil dilation) is a common anticholinergic side effect. The blockade of muscarinic receptors in the iris sphincter muscle leads to unopposed action of the dilator muscle, causing pupil dilation.
**Why Each Wrong Option is Incorrect**
**Option A:** Tachycardia is not a direct result of anticholinergic blockade, although it can occur due to increased sympathetic tone.
**Option B:** Sedation is a possible anticholinergic side effect, but it is not the most specific or direct result of anticholinergic blockade.
**Option C:** Dry mouth is a common anticholinergic side effect, but it is not related to the muscarinic receptors in the eye.
**Clinical Pearl / High-Yield Fact**
The anticholinergic side effects can be remembered using the mnemonic "hot as a hare, dry as the Sahara, red as a beet, and mad as a hatter."
**Correct Answer: D. Mydriasis**