Final answer:
A drug administered through the enteral route is given through the digestive system, involving the gastrointestinal tract. When medications are not well absorbed via this route, alternatives like parenteral administration are considered, particularly for higher plasma levels or specific treatments.
Step-by-step explanation:
A drug that has an enteral route of administration is given through the digestive system. This involves the gastrointestinal (GI) tract, which includes organs through which food passes during digestion, such as the mouth, esophagus, stomach, small and large intestines. Enteral administration is typically preferred when the medication can be conveniently taken at home and is well absorbed from the GI tract into the bloodstream.
However, when a drug is not absorbed in the GI tract, other routes like parenteral administration (intravenous or intramuscular injection) may be used. These methods are often performed in health-care settings and are chosen based on the desired plasma levels and the specific conditions being treated. For example, for systemic infections, oral administration could be appropriate and convenient for home use, while intravenous methods would provide higher plasma levels and might be preferred in a clinical setting.