What is a dry powder inhaler?
Dry powder inhalers or systems are an alternative method of delivering anti-asthma drugs by inhalation. These are breath-actuated. That means that the force of the patient’s inhalation generates the aerosol. Therefore, it is formed only when the patient breathes in. An example of such a system is a rotahaler-rotacap inhaler system.
A rotahaler is a device used for generation of powder aerosol. The drug is mixed with a powder, usually lactose and packed in gelatin capsules called rotacaps. There is a slot in the rotahaler into which the rotacap is inserted. When the lower half of the rotahaler is twisted, the rotacap breaks into two. After that, the patient breathes in rapidly. Due to the air currents generated by the patient’s breath, the drug powder gets aerosolized and is carried into the lungs along with the inspired air.
The rotahaler-rotacap system is suitable for the following category of patients:
- Young children, between ages 3 to 6 years as they are often unable to use the metered dose inhaler
- Adults who are unable to learn the proper technique of using a metered dose inhaler
Another dry powder inhaler system is a turbohaler. It is a device which comes packed with the powdered drug. There is a mechanism to release one dose at a time that is then inhaled.
Drugs available as dry powders:
Bronchodilators: Salbutamol (rotacaps), Terbutaline (turbohaler)
Anti-inflammatory: Beclomethasone (totacaps), Budesonide (turbohaler, rotacaps), Cromolyn sodium (rotacaps)