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RESPIRATORY SYSTEM › DRUGS FOR OBSTRUCTIVE AIRWAY DISEASES › ADRENERGICS FOR SYSTEMIC USE › Selective beta-2-adrenoreceptor agonists
fenoterol
R03CC04
Forms & Strengths
- Inhalation solution for nebulizer 0.5 mg/mL
- Metered‑dose inhaler (MDI) 100 µg per actuation
- Vial for nebulization 1 mg/2 mL
Adult Dosing
- Nebulizer: 0.5 mg (1 mL) 3–4 × daily PRN; max 2 mg/day
- MDI: 1–2 puffs (50–100 µg) every 4–6 h PRN; max 8 puffs/24 h
- Acute severe bronchospasm: 1 mg nebulized over 5 min, may repeat after 15 min
Pediatric Dosing
- Ages 2–12 y: nebulizer 0.25 mg (0.5 mL) 3–4 × daily PRN; max 1 mg/day
- MDI: 1 puff (50 µg) every 4–6 h PRN; max 4 puffs/24 h
- >12 y: adult dosing applies
Indications
- Relief of acute bronchospasm in asthma
- Bronchospasm associated with COPD
- Prevention of exercise‑induced bronchoconstriction
- Adjunct in reversible airway obstruction
Mechanism of Action
- Selective β2‑adrenergic receptor agonist
- Stimulates adenylate cyclase → ↑cAMP in bronchial smooth muscle
- cAMP‑mediated relaxation of airway smooth muscle and inhibition of mediator release
Contraindications
- Known hypersensitivity to fenoterol or formulation excipients
- Severe tachyarrhythmias or uncontrolled cardiac disease
- Paradoxical bronchospasm on inhalation
Adverse Reactions
- Tremor, especially of hands
- Palpitations, tachycardia
- Headache, dizziness
- Hypokalemia, especially with high doses
- Nausea, throat irritation
- Paradoxical bronchospasm (rare)
Drug Interactions
- Concurrent β‑blockers may diminish bronchodilatory effect
- Non‑selective β‑agonists may increase risk of cardiovascular side effects
- Diuretics, especially loop diuretics, may exacerbate hypokalemia
- MAO inhibitors or tricyclic antidepressants may potentiate sympathomimetic effects
- Other sympathomimetics (e.g., epinephrine) increase risk of tachycardia
Curated Content: Needs Vetting Before Put to Clinical Use