Final answer:
A drug administered transdermally passes through the skin, avoiding GI tract issues, and is suitable for gradual absorption into the bloodstream.
Step-by-step explanation:
A drug that is administered transdermally passes through the skin. This means that the medication is given in the form of patches, gels, or creams that release the drug over time through the skin, where it then enters the bloodstream. This route of administration avoids the need for the drug to pass through the digestive tract, which can be beneficial for drugs that are poorly absorbed from the gastrointestinal tract or that could be destroyed by the digestive system's enzymes.
The route of administration of a drug is critical, especially when treating systemic infections. For convenient home administration, an oral route is often preferred unless the patient is unable to take oral medications (e.g., due to vomiting). For drugs that need to bypass the gastrointestinal tract, or when higher plasma levels are required quickly, parenteral routes such as intravenous or intramuscular injections are used, typically in health-care settings.