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MDI's are generally known because we can see asthma patients usually have those with them in case of emergency of asthma exacerbation/ hyperreaction.

Despite that they seem simple to use for us, yet they require synchronization (you need to press the button to release the drug and inhale and the same time in order to get the drug to the RS where it act) and many patients usually fail to do this. And another common mistake is they don't leave a minute between every puff when they are asked to use 2 puffs or 4.

Thanks for reading through!