Final answer:
Atropine and scopolamine are muscarinic antagonists that can adversely affect older patients and children by disrupting autonomic regulation, potentially exacerbating conditions like glaucoma and causing symptoms like hallucinations in overdoses. Pilocarpine is an antidote to atropine poisoning.
Step-by-step explanation:
Atropine and scopolamine are muscarinic antagonists derived from the Atropa genus of plants, such as belladonna or deadly nightshade. Atropine blocks the muscarinic receptors and causes autonomic regulation disruption leading to anticholinergic symptoms. These effects can be particularly harmful to older patients and children due to their increased susceptibility to central nervous system and cardiovascular side effects. The cosmetic application of atropine, historically used for dilating the pupil, is no longer popular due to the potential for systemic suppression of parasympathetic function. In older patients, this can exacerbate conditions like glaucoma, urinary retention, and provoke confusion or memory impairment. Children are sensitive to atropine and may experience rapid involuntary movements and hallucinations as symptoms of overdose. For atropine poisoning, a muscarinic agonist such as pilocarpine can serve as an antidote by counteracting the effects of atropine.