Final answer:
Scopolamine is the preoperative drug used transdermally to prevent postoperative nausea. It is safe at the controlled doses provided by the patch, despite its potentially dangerous reputation at higher doses. Alternatives such as antihistamines like dimenhydrinate are available for those wary of scopolamine.
Step-by-step explanation:
The preoperative drug that is delivered transdermally to prevent postoperative nausea is Scopolamine. This drug is commonly used to treat motion sickness and is administered via a patch that releases the medication through the skin.
Scopolamine is derived from the Atropa genus, which also includes atropine. In controlled, low doses as delivered by the transdermal patch, scopolamine is safe and effective, despite its reputation at higher doses for being dangerous. The patch helps to regulate the release of the drug, avoiding the potential for an extreme sympathetic syndrome that can result from higher, unregulated doses.
For those who are hesitant about using scopolamine due to its strong effects at high doses, antihistamines such as dimenhydrinate (Dramamine®) offer an alternative treatment for motion sickness and nausea.