Which method involves introducing medication through the nasal passages?

The method that involves introducing medication through the nasal passages is intranasal administration. This technique utilizes the mucous membranes in the nasal cavity to absorb the medication directly into the systemic circulation. By using this route, medications can act quickly because the blood supply in the nasal region facilitates rapid absorption.

Intranasal delivery is particularly beneficial for medications that require fast action, such as those used in emergency situations (e.g., naloxone for opioid overdoses), or for certain vaccines. This method avoids the first-pass metabolism that occurs when drugs are taken orally, allowing for higher bioavailability.

Other methods, while effective in their own right, do not involve the nasal passages. Intravenous administration delivers medication directly into the bloodstream through a vein, subcutaneous administration involves injecting medication into the tissue layer between the skin and muscle, and inhalation involves delivering medications to the respiratory system. Each of these methods serves different therapeutic needs, but the unique characteristic of intranasal administration is its route through the nasal passages, leading to quick systemic effects.