Salmeterol

Long-Acting β₂-Agonist (LABA)

Generic Name

Salmeterol

Drug Class

Long-acting beta-2 adrenergic agonist bronchodilator (LABA)

Indications

Maintenance treatment of bronchial asthma (with inhaled corticosteroid)
Chronic obstructive pulmonary disease (COPD)
Prevention of exercise-induced bronchospasm

Dosage

Adults & children ≥4 years: 50 mcg inhaled twice daily
Exercise-induced bronchospasm: 50 mcg inhaled ≥30 minutes before exercise

Important: Always use with an inhaled corticosteroid in asthma.

Route of Administration

Inhalation (dry powder inhaler or metered-dose inhaler)

Mechanism of Action

Salmeterol selectively stimulates β₂-adrenergic receptors in bronchial smooth muscle, producing prolonged bronchodilation (≈12 hours). It has a slower onset but longer duration than short-acting β₂-agonists.

Common Adverse Effects

Tremor
Palpitations
Headache
Muscle cramps
Throat irritation

Serious Adverse Effects

Severe asthma exacerbation (if used without corticosteroid)
Tachyarrhythmias
Hypokalemia
Paradoxical bronchospasm (rare)

Contraindications

Monotherapy in asthma
Hypersensitivity to salmeterol

Precautions

Not for acute asthma attacks
Always prescribe with inhaled corticosteroids in asthma
Use cautiously in cardiac disease and hyperthyroidism

Drug Interactions

Beta-blockers – reduced bronchodilator effect
Diuretics – increased risk of hypokalemia
Strong CYP3A4 inhibitors – increased systemic effects

Pregnancy & Lactation

Use when benefits outweigh risks. Generally considered safe when used appropriately.

Patient Counseling

Not a rescue inhaler – do not use for acute symptoms
Use regularly as prescribed
Always combine with inhaled corticosteroid
Seek help if asthma worsens