Which of the following is a benefit of using a holding chamber with an MDI?

Using a holding chamber with a metered-dose inhaler (MDI) significantly reduces oropharyngeal deposition of medication, which is the primary reason why this option is the correct answer. When an inhaler is used without a holding chamber, a substantial portion of the medication can settle in the throat or mouth, leading to reduced effectiveness and increased side effects.

A holding chamber helps to keep the medication suspended in the chamber, allowing the patient to take a slower and more deliberate inhalation. This mechanism ensures that more of the medication reaches the lungs instead of being deposited in the oral cavity, where it has little therapeutic benefit.

By minimizing oropharyngeal deposition, the use of a holding chamber can enhance the overall efficacy of the medication by ensuring that a greater percentage of the dose reaches the targeted areas of the respiratory system. This is particularly important for patients with asthma, as it directly influences their control over their condition and reduces the likelihood of unwanted side effects associated with excessive oral deposition.