Which of the following routes is NOT typically used for drug administration?

The gastrointestinal route is primarily associated with oral administration of drugs, where medications are taken by mouth and absorbed through the digestive system. While gastrointestinal drug administration is common, the question specifically asks which route is NOT typically used for drug administration in the context provided.

In contrast, the other options—intramuscular, transdermal, and intravenous routes—are all well-established methods for administering drugs. Intramuscular administration involves injecting medication directly into a muscle, which can allow for faster absorption compared to oral routes. Transdermal administration involves the application of drugs through the skin to achieve systemic effects, while intravenous administration delivers drugs directly into the bloodstream, providing immediate onset of action.

Given the context of the question, it's important to clarify that while the gastrointestinal route is indeed a method of drug administration, it may not align with the intended interpretation of "not typically used" when compared to the other options, which represent more specialized or alternative methods of drug delivery.