Salmeterol is a long-acting β2-adrenergic agonist (LABA) for maintenance treatment of asthma and chronic obstructive pulmonary disease (COPD). It exerts prolonged bronchodilation (≈12 hours) by binding selectively to β2 receptors on airway smooth muscle. The molecule’s long lipophilic side chain anchors within the receptor’s exosite, permitting repeated stimulation of the active site and sustained relaxation of bronchial smooth muscle. Onset is slower than short-acting agents such as salbutamol/albuterol (typically 10–20 minutes vs 3–5 minutes), hence not suitable for acute relief.
In asthma, salmeterol is used only as add-on to an inhaled corticosteroid (ICS). Large safety analyses showed LABA monotherapy increases the risk of severe exacerbations and asthma-related death; the risk is mitigated when LABA is paired with ICS that treat the underlying airway inflammation. In COPD, where eosinophilic inflammation is less dominant, salmeterol can be used alone for symptom control, or combined with ICS and/or a long-acting muscarinic antagonist (LAMA) according to guideline-based step-up therapy.
Salmeterol improves FEV1, reduces night-time and exercise-induced symptoms, decreases rescue inhaler use, and lowers exacerbation rates when used appropriately. Benefits depend on correct device technique and adherence. Preparations include dry-powder inhalers (Diskus/Accuhaler) and metered-dose inhalers (Evohaler). Combination ICS/LABA products (e.g., fluticasone/salmeterol) simplify regimens and reduce monotherapy risk.
Because β2 agonists can cause systemic effects (tremor, palpitations) especially at high doses or with incorrect technique, patient education is essential. Review technique at every visit; even experienced users benefit from periodic refresher training and a written action plan.
Personalised plans should specify the daily controller therapy, reliever use, and what to do when symptoms worsen (action thresholds for stepping up or seeking urgent care).
Adverse effects reflect β2 stimulation and systemic absorption. Many are dose-related and improve with correct technique and appropriate dosing.
Report persistent palpitations, chest pain, severe tremor, or worsening control. Reassess dose, timing, and device; consider step-up of anti-inflammatory therapy if symptoms persist.
Provide a written asthma/COPD action plan and schedule routine reviews to reassess symptoms, exacerbations, and inhaler technique.
Both pharmacodynamic and pharmacokinetic interactions can modify response or safety:
Patients should share a full list of medicines and supplements with clinicians, avoid starting OTC decongestants/NSAIDs for breathlessness without advice, and report new palpitations or tremor.
Overdose: Features include chest pain, tachycardia, arrhythmias, tremor, headache, anxiety, and hypokalaemia. Management is supportive—monitor ECG and electrolytes, correct potassium, and treat arrhythmias. In severe cases, a cardio-selective β-blocker can be used with caution in patients without active bronchospasm and with close monitoring.
Accidental double dose: Usually causes transient tremor or palpitations. Rest, avoid caffeine and strenuous activity, and monitor symptoms. Seek medical advice if symptoms are severe or you have underlying heart disease.
Missed dose: Take when remembered if not close to the next scheduled dose; otherwise skip and resume usual twice-daily schedule. Do not double up. Always keep a rapid-acting reliever available.
Action plan tip: If symptoms are worsening (increased reliever use, night waking, peak flow dropping), escalate per your plan and contact your clinician—do not self-increase salmeterol frequency.
Travel tip: Carry inhalers in hand luggage, not checked bags. Extreme temperatures and pressure changes can affect canisters; keep a spare reliever inhaler available.
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