Which condition is commonly treated with OTC sleep aids that have anticholinergic properties?

• A. Asthma
• B. Motion sickness
• C. Insomnia
• D. COPD

Answer: (C)

Insomnia is what these OTC sleep aids target. Sedating antihistamines like diphenhydramine or doxylamine provide sleep help by blocking histamine H1 receptors in the brain, which promotes drowsiness and makes it easier to fall asleep. The same drugs carry anticholinergic effects from blocking muscarinic acetylcholine receptors, leading to dry mouth, blurred vision, constipation, urinary retention, and, especially in older adults, confusion or delirium. Because of these anticholinergic risks and the tendency for tolerance with regular use, they’re advised only for short-term relief of insomnia. They aren’t treatments for asthma or COPD, which require bronchodilators and anti-inflammatory therapies, and although some anticholinergic sleep aids can cause drowsiness that might help with motion sickness, their primary, common use is for insomnia.