Formoterol

How it works

It stimulates beta2 adrenoceptors on airway smooth muscle to cause bronchodilation, combining a rapid onset of action with a prolonged duration of effect.

Prescribing in practice

• In asthma it must never be used without a concurrent inhaled corticosteroid, as long-acting beta2 agonist monotherapy is associated with increased asthma deaths.
• Common effects include fine tremor, headache and palpitations, with risk of hypokalaemia especially alongside corticosteroids, diuretics, theophylline or hypoxia.
• Use with caution in cardiovascular disease, thyrotoxicosis and where QT-prolonging drugs are co-administered.

Monitoring

Monitor asthma or COPD control and reliever use, heart rate, and serum potassium in patients at risk of hypokalaemia during severe exacerbations.

Counselling the patient

• Always use alongside your preventer inhaler if prescribed for asthma.
• Report increasing reliever need or worsening breathlessness.
• Mild shaking or a faster heartbeat can occur and usually settles.

Evidence & guidelines

A well-established long-acting beta2 agonist underpinned by extensive asthma and COPD trial data, including its use in maintenance-and-reliever regimens, consistent with UK guidance.