Albuterol (Salbutamol)
Albuterol, also known as salbutamol, is a short-acting beta-2 agonist used in adults and children for the rapid relief of bronchospasm in asthma and chronic obstructive pulmonary disease. It produces bronchodilation within minutes after inhalation.
- Chemical formula
- C13H21NO3
- CAS number
- 18559-94-9
- ATC code
- R03AC02
- Molecular weight
- 239.31 g/mol
- Drug class
- Short-acting beta-2 agonist (SABA)
- Also known as
- Salbutamol, Albuterol
What is it?
Albuterol is the United States non-proprietary name for the molecule known as salbutamol in most other regions. Approved in the late 1960s, it remains the most widely used short-acting beta-2 agonist in respiratory medicine. The molecule is supplied as inhalation aerosol with metered-dose inhalers, dry powder inhalers, nebuliser solution, oral tablets and oral syrup. The clinically relevant formulations for acute relief are inhaled.
Mechanism of action
Albuterol selectively activates beta-2 adrenergic receptors on bronchial smooth muscle, leading to relaxation of the airways and rapid bronchodilation. It also reduces release of inflammatory mediators from mast cells in the short term and modestly enhances mucociliary clearance. At higher systemic concentrations, it can also activate beta-2 receptors elsewhere, which contributes to side effects such as tremor and tachycardia.
Pharmacokinetics
After inhalation, the onset of bronchodilation is within five to fifteen minutes, with peak effect at thirty to ninety minutes and duration of action of three to six hours. Only a small fraction of the inhaled dose enters systemic circulation. Oral bioavailability is approximately 50%. Albuterol is metabolised in the liver and excreted in urine. The R-enantiomer (levalbuterol) is also marketed separately as a single isomer in some countries.
Indications
Albuterol is approved in adults and children for the relief of bronchospasm in asthma and reversible airway obstruction in chronic obstructive pulmonary disease. It is also used to prevent exercise-induced bronchospasm and as part of nebulised therapy in acute exacerbations. According to current guidelines, albuterol monotherapy is no longer recommended in persistent asthma, where a controller medication should always be added.
Safety profile
Common adverse effects include tremor, palpitations, tachycardia, nervousness and headache, especially with frequent or high-dose use. Hypokalaemia can occur with high-dose nebulised therapy, particularly when combined with corticosteroids or diuretics. Frequent need for albuterol indicates poorly controlled disease and an increased risk of severe exacerbations. According to the prescribing information, patients should be reassessed by a clinician when use exceeds defined thresholds.
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Frequently asked questions
How quickly does albuterol work? ▾
After inhalation, albuterol typically produces noticeable bronchodilation within five to fifteen minutes, with peak effect at thirty to ninety minutes. The duration of effect is approximately three to six hours. According to the prescribing information, the inhaler is used for acute relief of bronchospasm or before anticipated triggers such as exercise. Persistent or severe symptoms should be addressed urgently.
Why is using albuterol every day a warning sign? ▾
Frequent need for a short-acting beta-2 agonist indicates uncontrolled airway inflammation in asthma and is associated with increased risk of severe exacerbations and mortality. According to international guidelines, the threshold of two or more uses per week (excluding pre-exercise prophylaxis) should prompt review of the maintenance regimen. Treating asthma only with albuterol is no longer recommended.
Can albuterol be combined with other respiratory medications? ▾
Yes. Albuterol is frequently combined with inhaled corticosteroids, long-acting beta-2 agonists, long-acting muscarinic antagonists or leukotriene antagonists in chronic asthma and COPD. Combined inhalers exist for several pairings. According to the prescribing information, the choice and order of inhalers, and the spacing between them, should be defined by the prescriber and reviewed at every relevant consultation.
Are there cardiac risks with albuterol? ▾
Albuterol is selective for beta-2 receptors, but at high doses it can also stimulate beta-1 receptors in the heart, producing palpitations or tachycardia. Caution is required in patients with ischaemic heart disease, severe hypertension, hyperthyroidism or arrhythmias. According to the prescribing information, the medical history must be reviewed by a clinician before any prescription, with closer monitoring in cardiovascular comorbidity.
What are the main contraindications for albuterol? ▾
Albuterol is contraindicated in known hypersensitivity to the molecule. Caution is required in tachyarrhythmias, severe ischaemic heart disease, hyperthyroidism, severe hypertension, hypokalaemia and during pregnancy and breastfeeding. According to the prescribing information, the medical history and current medication list must be reviewed by a clinician before any prescription, particularly when other beta-agonists or sympathomimetics are already being taken.
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