Which drug administration method is characterized by a rapid response and requires sterile conditions?

The method characterized by a rapid response and requiring sterile conditions is injection. When a drug is administered via injection, it is delivered directly into the bloodstream or tissue, allowing for quick onset of effects compared to other methods. This rapid response is crucial in medical settings where immediate drug action is necessary, such as in emergencies.

Moreover, injections must be performed in sterile conditions to prevent infection. Contaminated equipment or drugs can lead to serious complications, including infections or other adverse reactions. Maintaining sterility during the preparation and administration of injectable drugs is essential to ensure patient safety and treatment efficacy.

In contrast, methods such as inhalation, oral ingestion, and topical application do not require the same level of sterility or provide the rapid response characteristic of injections. Inhalation may produce quick effects but is less immediate than injections, and oral ingestion involves the digestive system, which delays onset. Topical application affects localized areas and does not provide systemic effects quickly. Thus, injection stands out as the method that fulfills both criteria of rapid response and the need for sterile conditions.