Which antiemetic medication can lead to anticholinergic side effects?

Scopolamine is an antiemetic medication that is known for its anticholinergic properties. It is primarily used to prevent nausea and motion sickness and is often administered via a transdermal patch. Anticholinergic side effects may include dry mouth, blurred vision, constipation, urinary retention, and cognitive impairment, particularly in older adults. These effects arise because scopolamine blocks the action of acetylcholine, a neurotransmitter involved in various bodily functions, including those that regulate gastrointestinal motility and secretions.

In contrast, the other medications listed do not have significant anticholinergic effects. Ondansetron and granisetron are serotonin (5-HT3) receptor antagonists, primarily acting to block serotonin in the central nervous system and gastrointestinal tract to prevent nausea and vomiting, particularly from chemotherapy or surgery. Metoclopramide, although it has some prokinetic effect and can be used for nausea, mainly acts through dopamine receptor antagonism and does not possess the same level of anticholinergic activity as scopolamine. Thus, scopolamine is specifically notable for its potential to cause anticholinergic side effects.