No. This blog is not about any miracle drug or vaccine against SARS Co-V2 virus responsible for the current deadly pandemic of COVID19. This is regarding the class of medications already invented & used by millions of people across the globe daily - by force or by choice. They are inhaler medications or as commonly called "Pump".
Let me briefly narrate the evolution of inhaler medicines.
Before the era of modern medicine, concept of drug delivery through inhalation route was mainly through nose & mediated by vapors, leading to the term, "medicated vapors". It was only after 1850s, the idea of generating 'aerosols' for the purpose of inhalation by breaking liquid gained momentum. Few devices were designed which can be classified in to "Atomizers" which did the same without baffle & "Nebulizers" which required baffle. (Modern Jet Nebulizer in image below)
In 1950s, with invention of Metered Dose Inhaler (MDI) & suitable formulations like salbutamol, the management of airway diseases got revolutionized as the device become small, portable & handy. Slowly, modifications came in & today we have numerous varieties of inhalers - pressurized MDIs, Breath Actuated MDIs, MDI with Spacer, Dry Powder Inhaler(DPI) with different devices, Multidose DPIs, Jet nebulizer, Mesh nebulizer etc, which all have their own pros & cons, requiring utmost caution in prescribing to suitable person.
When we look back into the history of respiratory diseases other than tuberculosis - the decade of 1950 holds the greatest significance. Apart from the first MDI being invented, two more significant developments happened. The primary aim of the inhaler medication at that time was "symptomatic relief". However with discovery of "Timed Vital Capacity" which is commonly known as "Forced Expiratory Volume in 1st Second or FEV1", put the edifice of further research for the efficiency of inhaler molecule - the increase in FEV1 or holding the rate of decline in FEV1 - became the standard endpoints in many clinical trials.
The third significant development was understanding of the "Obstructive Airway Diseases" evolved with description of elements of 'Chronic Obstructive Pulmonary Disease or COPD" in CIBA guest symposium in the year of 1959. Slowly the elements of Asthma, COPD & Bronchiectasis became more clear.
In conclusion, the understanding of airway diseases, its measurement of impact & the treatment - all got revolutionized in this decade.
As mentioned earlier, symptomatic relief was the chief indication of inhaler medications at that time. The molecules available were sympathomimatics - or relievers as we know them now, which manifests an important phenomenon called "Tachyphylaxis", meaning rapid & short term development of drug tolerance. Elaborating, if the person required 2 puffs to control the symptom, slowly over period of some time, one will require more than that dose to control the symptoms & hence becomes "addicted" - as the inhaler medication requires to be taken more frequently to control the symptom.
However, this is not the case with other class of molecules which are known as anti-cholinergics acting as "bronchodilators - to widen the narrowed airways" and inhaled corticosteroids acting as "anti-inflammatory - to reduce inflammation on airways".
As the understanding in the diseases & their management evolved, inhaled corticosteroids became the first line management to treat Asthma : known as 'controller' with aim to take 'relievers' as much less time as possible : a defining criteria to assess asthma control. There was enough evidence to suggest the shift, that in the year of 2019 - GINA made fundamental change in the recommendation that even in intermittent asthma - "SABA only" (read reliever only') treatment got abandoned.
Symbolism : A Pulmonologist passes through lot of thought processes to choose an inhaler just like Hanumam's struggle to fetch the herb. An optimized inhaler therapy reduces the symptom (particularly of breathlessness) & risk of the disease - just as sanjivani cured army to conquer the evil.
Sanjivani : a miracle herb described in the ancient scripture of "Ramayana", was obtained by Hanumanji after unprecedented struggle. Very few people know that the herb was actually "inhaled" leading to restoration of the army lead by Lord Shri Ram to conquer the evil. This blog provides holistic information of inhaler medications.
Part-2 of this blog series briefly narrates the historical aspect & evolution of inhaler medications.
- Dr. Jaykumar Mehta
MBBS (Gold Medalist)
MD, DNB, MNAMS, PD Fellow (Pulmonology)
Consultant Interventional Pulmonologist (Zydus Hospital, Ahmedabad)