Meter-Dosed Inhaler (MDI) administration is delivered by which route?

• A. Inhaled
• B. Intravenous
• C. Oral
• D. Sublingual

Answer: (A)

Meter-Dosed Inhalers deliver medication by inhalation, taking the drug directly into the lungs where it acts on the airway smooth muscle. This inhaled route provides a rapid local effect for bronchodilation and tends to have fewer systemic side effects than swallowing the medicine. When you actuate the inhaler, the aerosol is inhaled through the mouth and travels into the airways, and using a spacer or proper technique helps more drug reach the lungs for quick relief, which is especially important in acute respiratory episodes. The other routes don’t apply to an inhaler: intravenous would require an injection, oral means swallowing the drug (with first-pass metabolism), and sublingual involves absorption under the tongue.