Press down on your metered-dose inhaler (MDI). A fine, medicated mist puffs out. Then, a split second later, it disappears into thin air.
That’s how fast you must coordinate using an MDI and breathing in the inhaler’s medicine. To effectively treat asthma symptoms using an MDI, you must inhale at just the right moment and just the right speed – but catching that fleeting dose in a slow, deep inhalation is often very difficult.
Studies show that less than one-fourth of medicine delivered by an MDI actually makes it into the airways. The rest ends up lost in air or stuck on the tongue, sides of cheeks or back of the throat.
Read the rest of the article: The Ins and Outs of Holding Chambers