Dry powder inhalers (DPI) are an alternative to the aerosol-based inhalers commonly called metered-dose inhalers (or MDI). The medication is commonly held either in a capsule for manual loading or a proprietary form inside the inhaler. Once loaded or actuated, put the mouthpiece of the inhaler into your mouth and take a fast, deep inhalation and hold your breath for 5 to 10 seconds. Most DPIs rely on the force of inhalation to allow the powder to go from the device and break into aerosol particles that are small enough to reach the lungs. Insufficient inhalation flow rates may lead to reduced dose delivery. DPIs are normally used in older children and adults. Some powder inhalers use lactose to aid in powder uptake from the device during inhalation. The amount of lactose delivered by dry powder inhalers is typically less than a few milligrams and such small doses do not lead to clinically relevant concerns of adverse effects in lactose intolerant patients. DPI medication must be stored in a dry place or sealed packaging, since exposure of the powder to moisture degrades the ability of the device to disperse its medication as an aerosol upon inhalation.