Dry-Powder Inhalers

Chapter 108


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Dry-Powder Inhalers


Ariel Berlinski, MD, FAAP


Introduction


Dry-powder inhalers (DPIs) are devices than can deliver medications to the lungs without the need for a suspending medium.


DPIs are mainly used in pediatric patients to treat asthma (bronchodilators, corticosteroids, and combination corticosteroid and long-acting bronchodilator) and cystic fibrosis (tobramycin).


Currently, all devices available in the United States are passive and breath actuated.


The inspiratory force (peak inspiratory flow) required of the patient to overcome the internal resistance of the device is responsible for the deagglomeration of the dry powder when it is released from the device.


A minimum inspiratory flow threshold is needed (30–40 L/min for most devices).


For most devices, the higher the inspiratory flow, the higher the intrapulmonary deposition of the drug.


DPIs can deliver larger quantities of drugs than pressurized metered-dose inhalers.


Many formulations use a carrier, such as lactose.


The advantages and disadvantages of the use of DPIs are listed in Box 108-1.


Types of DPI Devices


There are many configurations of DPI devices.


Single-dose devices (Figure 108-1)


These devices require placement of a capsule in the device.


Multidose devices (Figure 108-2)


Common reservoir


Individually packed blister strips or cartridge


Incorporated dose counters


Proper use of DPIs


Dose Preparation


The dose to be inhaled has to be loaded in the device.


For some devices, this step automatically occurs when the patient opens the device or removes the cap.


Aug 22, 2019 | Posted by in PEDIATRICS | Comments Off on Dry-Powder Inhalers
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