The Early History of Inhaled Asthma Treatments
Humans have suffered from asthma and other respiratory conditions since ancient times. Several early civilizations developed primitive methods to try to alleviate asthma symptoms. The ancient Greek physician Hippocrates, known as the "Father of Medicine," mentioned the use of inhaled steam and smoke from medicinal plants to treat coughs and breathing difficulties over 2,000 years ago.
Use of Medicinal Smoke Throughout History
Many ancient medical traditions made use of medicinal smoke from herbs and plants such as datura, henbane, and stramonium. These smoke mixtures contained compounds with bronchodilating properties, providing temporary relief of wheezing and chest tightness caused by asthma. Burning anti-asthma herbs and inhaling the medicinal smoke is one of the earliest forms of an inhalable asthma treatment.
This practice continued through the Middle Ages in various parts of the world. French physician Henri Étienne Tessier published a book in 1689 recommending datura smoke for the treatment of asthma. Many traditional medical systems in India and Asia also burned a variety of anti-asthma herbs and had patients inhale the medicinal smoke.
Early Simple Inhalers
By the 1800s, physicians began looking for more convenient methods to administer inhaled asthma medications. Simple handheld inhalers and breathing apparatuses were developed, using cloth, paper, or sponges soaked with asthma solutions for patients to inhale.
An early inhaler invented in 1860 by Nelson Downing was a simple wire device filled with stramonium leaves to be burned and inhaled. In 1877, John Mackenzie created an inhaler device utilizing blotting paper soaked in a belladonna preparation.
The Invention of Modern Pressurized Inhalers
In the 20th century, the invention of pressurized aerosol canisters led to the development of metered dose inhalers. This allowed more precise doses of inhaled asthma medications to be administered.
First Pressurized Inhalers
The first pressurized canister inhaler for asthma was the Pneumostat, invented in 1956 by three doctors at Carolina Medical Center. It contained isoprenaline sulfate, an early bronchodilating asthma medication. The Medihaler-Iso developed by Riker Laboratories soon followed in 1959 as an alternative pressurized isoprenaline inhaler.
These early canister inhalers used chlorofluorocarbon (CFC) propellants to spray medication out of the inhaler. However, CFCs were later banned due to environmental concerns over damage to the ozone layer.
Transition to CFC-Free Inhalers
As CFC propellants were phased out in the 1980s and 90s, pharmaceutical companies developed hydrofluoroalkane (HFA) propellants as an alternative for pressurized metered dose inhalers. Ventolin HFA, introduced in 1996 by GlaxoSmithKline using the HFA propellant HFA-134a, was one of the first CFC-free rescue inhalers for asthma.
Various other CFC-free pressurized inhalers for treating asthma have since come to market using propellants like HFA-227 or HFA-152a. These next generation HFA inhalers are just as effective while no longer using ozone-harming CFC propellants.
Recent Innovations in Asthma Inhaler Technology
While pressurized metered dose inhalers have remained largely unchanged in underlying form for over 50 years, some recent innovations are also aiming to improve inhaler convenience and medication delivery.
Breath Actuated Inhalers
Traditional pressurized asthma inhalers require pressing down on the canister to release medication, which can be difficult to coordinate while inhaling. Breath-actuated metered dose inhalers have been developed that instead automatically release a puff of medication when the patient begins to inhale.
These types of asthma inhalers, like QVAR RediHaler and ProAir Digihaler, eliminate the need to press down and inhale simultaneously. The medication is automatically dispensed upon sensing the patient's inhaling breath.
Smart and Connected Inhalers
Several companies are also working on Bluetooth-enabled "smart" inhalers containing built-in sensors, connectivity, and companion apps. These connected inhalers can track medication usage, monitor inhaler technique, and send reminders about taking doses.
Smart inhaler company Propeller Health was acquired by ResMed in 2018. Products like the Propeller Sensor for metered dose inhalers and the Gecko Health Inhaler System are other recently launched smart inhaler technologies now available.
By providing real-time feedback, notifications, statistics and asthmas management tools, these newly innovated inhalers aim to improve patient compliance and make it easier for doctors to analyze and optimize asthma treatment regimens.
FAQs
What were some of the earliest asthma inhalation treatments?
Some of the earliest asthma treatments involved inhaling the medicinal smoke from burned herbs and plants like datura, henbane, and stramonium. These contained compounds that provided temporary relief of asthma symptoms.
When was the first pressurized canister asthma inhaler invented?
The first pressurized metered dose asthma inhaler was the Pneumostat, invented in 1956. It contained the bronchodilating medication isoprenaline sulfate in a canister under pressure to deliver inhaled doses.
Why did asthma inhalers stop using CFC propellants?
CFC propellants were initially used to spray medication out of pressurized asthma inhalers. However, CFCs were banned due to environmental concerns over damage to Earth's ozone layer.
What are some recent innovations in inhaler technology?
Some recent asthma inhaler innovations include breath-actuated inhalers which release medication when a person starts inhaling, as well as Bluetooth-enabled “smart” inhalers that can track usage and provide feedback through a mobile app.
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.
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