Salbutamol inhalers are known as ‘reliever’ inhalers which relieve symptoms of certain medical conditions affecting the airways. These are very commonly prescribed by doctors.

Indications

• Asthma - to be taken when required for symptomatic relief.

• Prophylaxis of exercise or allergen-induced asthma - to be taken 10-15 minutes before challenge.

• Other conditions associated with reversible airway obstruction such as COPD.

Mechanism of action

Salbutamol is known as a SABA (short-acting beta 2 receptor agonist.) Beta 2 adrenoceptors are found in airway smooth muscle tissue. Therefore, by activation beta 2 receptors salbutamol relaxes bronchial smooth muscle. This then leads to an increased uptake of potassium into cells which aids in muscle relaxation, reduction of inflammation and maintaining an electrolyte balance. Salbutamol also stimulates the uptake of cAMP which promotes bronchodilation, has anti-inflammatory effects and inhibits the degranulation of mast cells. These collectively lead to a relief of asthma attack symptoms.

Reliever vs preventer inhaler

It is important that patients are advised to take their preventer inhalers regularly to reduce asthma attacks severity and frequency. Salbutamol has a very short duration of action of about 4 hours. Whereas, the drugs found in preventer inhalers are much longer lasting with a duration of around 8-12 hours so a twice daily dose of this inhaler is sufficient to help keep asthma symptoms at bay.

Side effects

• Common or very common: muscle cramps

• Rare or very rare: akathisia (restlessness); hypokalaemia (with high doses); vasodilation

• Frequency unknown: metabolic change, myocardial ischaemia

• Specific side effects: (inhaled salbutamol) oral irritation; throat irritation

Pregnancy & breastfeeding counselling points

Pregnant women/women planning to become pregnant should be counselled about the importance of taking their asthma medication regularly (e.g., their preventer inhaler) to maintain good control of their asthma symptoms.

Inhaled drugs can be taken as normal during breastfeeding.

Useful videos

These are some videos which I found very useful in explaining the pharmacology of salbutamol as well as how to use a pressurised metered-dose inhaler and a breath-actuated inhaler. Showing a patient how to use their inhaler can seem daunting, especially if we don’t use one ourselves but there is nothing to worry about!

The PillBox