Final answer:
Parenteral administration, including intravenous or intramuscular injection, is a potential route when oral medications are contraindicated, being suitable for achieving higher plasma levels needed to treat infections.
Step-by-step explanation:
When oral medications are contraindicated, parenteral administration is considered a potential route. Parenteral administration includes methods such as intravenous or intramuscular injection, which are typically performed in health-care settings.
This route is often preferred when a drug is not easily absorbed through the gastrointestinal (GI) tract or when a patient is unable to take oral medications due to illness, as it can achieve higher plasma levels for treating infections.