Inhaler

Inhaler

An inhaler, also known as a puffer, is a medical device utilized for administering medication directly into the body through the lungs. It finds primary application in treating conditions such as asthma and Chronic Obstructive Pulmonary Disease (COPD). Notably, Zanamivir (Relenza), a medication for influenza treatment, requires administration via inhaler.

To minimize deposition in the mouth and throat, and to alleviate the need for precise coordination between inhalation initiation and device actuation, Metered Dose Inhalers (MDIs) are often accompanied by a spacer or holding chamber device. The MDI comprises a canister containing medication, usually stored in solution form, along with a propellant or suspension. The correct usage entails exhaling fully, placing the mouthpiece in the mouth, initiating a moderate inhalation, and then depressing the canister to release the medicine. The aerosolized medication is inhaled deeply, held for 10 seconds, allowing it to settle within the airways.

There are several types of inhalers:

1. Metered-Dose Inhalers (MDIs): These are the most common, releasing medication in aerosol form from a pressurized canister via an actuator.
2. Dry Powder Inhalers (DPIs): These dispense powdered medication measured by the device, inhaled through a DPI device.
3. Nebulizers: Nebulizers supply medication as an aerosol generated from an aqueous formulation.

In addition to these, there are specialized inhalers like analgesic inhalers, exemplified by the Analgizer developed by Robert Wexler in 1968. It allowed self-administration of methoxyflurane vapor for analgesia. The Analgizer was deemed safe and effective for labor analgesia, fracture pain relief, and burn dressing changes, among other applications, until its withdrawal in 1974.

Propellants used in inhalers underwent a transition in 2009, with the FDA banning chlorofluorocarbons (CFCs) and mandating hydrofluorocarbons (HFA) due to environmental concerns. Although some patients expressed concerns about the effectiveness and cost of HFA inhalers compared to their CFC counterparts, clinical studies indicate equivalent asthma control with HFA inhalers.