Comparing Metered-Dose Inhalers to Wet Nebulizers

Is it All in the Delivery When it Comes to Bronchodilators?

Picture of Nebulizer
Nebulizer. A.D.A.M.

The theory that wet nebulizers are better than metered-dose inhalers (MDIs) when it comes to treating lung diseases like COPD is seemingly unfounded, as studies suggest that MDIs are equal in comparison and in fact, less expensive. Let's take a look at the difference between the two:

Understanding Their Differences

An MDI is a plastic and metal device that delivers a specific amount of COPD medication in an aerosol form that can then be inhaled directly into the lungs.

MDI's are commonly used to treat asthma, COPD, and other respiratory conditions. A device called a spacer or holding chamber, should always be used with your MDI. This device catches the mist as it leaves the MDI and allows you to get more medication, with less residual left in your mouth. It also prevents you from having to worry about coordinating your breath in with the "puff" of the medication from the MDI.

In contrast, the nebulizer is an electronic device that transforms liquid into a very fine mist, which is then inhaled deeply into the lungs. It is also used to treat respiratory conditions such as asthma and COPD. This type of device requires that you measure the amount of medication carefully and pour it into a cup attached to the nebulizer tubing.

In order to get the most from your inhaler device, it is important to use them properly by following the instructions carefully. Read more about how to use a nebulizer or metered-dose inhaler.

Comparing the Two

Compared to the MDI, nebulizers seem to be a favorite in hospitals for a variety of reasons - they are easy to use, they can be easily adapted for use with a mouthpiece, mask, tracheostomy collar, or for an intubated patient, and they can deliver a host of different COPD medications.

And, while proper technique is important for both devices, it is a general consensus that there is more room for error when it comes to using the MDI. In fact, one study showed that only five percent of all patients used the MDI correctly. This number significantly improved, however, after patient teaching was performed by health care professionals. But, when all is said and done, which method of delivery is better?

MDI versus Nebulizer: Will the Winner Please Rise

The belief that nebulizers work better may coincide with the duration of inhalation - up to 20 minutes. As we breathe in the fine mist delivered by the nebulizer for a long period of time, compared to that of the MDI (which is only seconds), we may believe we are getting more medication, hence, the more-is-better mentality. But, what are the facts? Does the nebulizer actually work better than the MDI and thus provide better outcomes for COPD patients? Research, in fact, suggests the opposite.

In 2002, wet nebulizer treatments were the main course of initial treatment for people with acute asthma in hospital emergency rooms. This changed however, in 2003, when hospitals switched to the MDI in an attempt to improve patient treatment goals.

A subsequent study was done to evaluate the impact of the change and the results were very interesting. Those in the MDI group showed a significant reduction in length of emergency room stay and more were released in the first two hours of treatment. Although the percentage of patients finally discharged from the hospital were similar in both groups, the patients treated with MDIs were shown to improve faster.

Another study showed that MDIs with spacers were associated with fewer side effects, namely anxiety and tremor. They were also less expensive and while some may say nebulizers deliver more medication, research suggests they have no added clinical benefit.

So, what does this mean for patients who have COPD? If you are using a nebulizer or MDI, should you switch from one to the other?

Conclusion: Don't Fix What's Not Broken

Have you been using your nebulizer and find that it is effective in providing you relief from the bothersome symptoms of COPD? Or, does your metered-dose inhaler seem to work better for you? If cost is not an issue and, if they are both as effective, then why bother switching? Remember the old saying that you should not fix what is not broken? This easily applies to bronchodilator delivery for treatment of COPD. The bottom line, use what your health care provider prescribes for you and if you don't know how to use it, ask for instructions. Additionally, only a doctor can prescribe a nebulizer or metered-dose inhaler for the treatment of COPD. It is always unwise and unsafe to use someone else's medication or inhaler for any health condition or any reason.


Newman, KB et al. A comparison of albuterol administered by metered-dose inhaler and spacer with albuterol by nebulizer in adults presenting to an urban emergency department with acute asthma. Chest April 2002;121: 1036-41.

Wolfe, John A. Nebulizers VS Inhalers: And the Winner Is? August, 2004.

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