by John Betts, Keeper of the RPS Museum
2019 marks the 50th anniversary of the landmark asthma treatment Salbutamol becoming commercially available in the UK. Salbutamol is still widely used today to relieve symptoms of asthma and COPD such as coughing, wheezing and feeling breathless. It works by relaxing the muscles of the airways into the lungs, making it easier to breathe.
Launched in 1969 with the brand name Ventolin, Salbutamol revolutionised the treatment of bronchial asthma.
It treated bronchospasm far more effectively compared with previous bronchodilators and had fewer side effects.
To understand how much of a breakthrough Salbutamol was in the treatment of asthma, it’s first worth comparing it to the drugs that were used to treat asthma before 1969.
One of the main drugs used for treating asthma in the mid-1960s was isoprenaline. This is a powerful bronchodilator and was used to relieve bronchospasm. However, the side effects include a sudden increased heart rate. Between 1963 and 1968 in the UK there was an increase in deaths among people using isoprenaline to treat asthma. This was attributed to overdose due to both excessive use of the aerosols and the high dosage they dispensed.
In the mid-1960s the mortality rate for asthma sufferers had risen to over 2,000 deaths a year. An effective bronchodilator was desperately needed that did not stimulate the heart or affect blood pressure.
Salbutamol was discovered in 1966 by a research team at Allen and Hanburys (a subsidiary of Glaxo). Salbutamol was the first drug that selectively targeted specific receptors in the lungs, inhibiting the production of proteins needed to produce muscle contractions. It works by relaxing the smooth muscle of the airways, opening them up and so lessening or preventing an asthma attack. Not only was Salbutamol a good bronchodilator, it lasted longer than isoprenaline, and inhalation caused fewer side effects.
In addition to the effectiveness of the drug, the method of administration itself was also revolutionary. The Ventolin inhaler was designed to ensure metered aerosol doses of Salbutamol were inhaled straight into the patient’s lungs.
The drug was an instant success.
The only real deficiency of Salbutamol was its short duration of action; at 4 hours it couldn’t prevent night-time asthma attacks. In response to this the pharmaceutical manufacturer Glaxo aimed to develop a longer acting drug. The result of their research was Salmeterol. Launched in 1990 with the brand name Serevent, it had a 12-hour duration of action.
50 years on Salbutamol is still on the World Health Organization’s List of Essential Medicines; a testament to the major role it continues to play in the treatment of asthma.
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