Formoterol is a long-acting beta-2 adrenergic agonist (LABA) that selectively stimulates beta-2 receptors in bronchial smooth muscle. This activation leads to:

1. Relaxation of bronchial smooth muscle: Via increased cyclic AMP (cAMP), reducing airway resistance.
2. Inhibition of mast cell mediators: Reducing inflammation and bronchoconstriction.
3. Enhanced mucociliary clearance: Improves airway function.

Formoterol has a rapid onset of action (1–3 minutes) and a long duration of effect (up to 12 hours), making it suitable for both maintenance and relief therapy in asthma and chronic obstructive pulmonary disease (COPD).

Formoterol is indicated for:

1. Asthma:
   • Maintenance therapy in combination with inhaled corticosteroids (ICS).
   • Symptom relief in mild asthma (as part of a single maintenance and reliever therapy, SMART regimen).
2. Chronic Obstructive Pulmonary Disease (COPD):
   • Maintenance therapy to improve lung function and reduce exacerbations.
3. Exercise-Induced Bronchoconstriction:
   • Prophylaxis before exercise.

Adults and Adolescents (≥12 years):

• Asthma/COPD: 6–12 mcg twice daily via inhalation.
• SMART Regimen: 6 mcg as needed for symptom relief (max 72 mcg/day).
• Exercise-Induced Bronchoconstriction: 6–12 mcg 15 minutes before exercise.

Children (6–11 years):

• Asthma: 6 mcg twice daily (max 12 mcg/day).

Special Populations:

• Renal/Hepatic Impairment: No dose adjustment required.
• Elderly: Use with caution; monitor for cardiovascular effects.

• Common: Tremor, headache, palpitations, muscle cramps.
• Serious:
  • Cardiovascular: Tachycardia, arrhythmias, angina.
  • Hypokalemia: Due to intracellular potassium shift.
  • Paradoxical Bronchospasm: Rare; discontinue if occurs.
  • Allergic Reactions: Rash, angioedema.

1. Asthma Mortality Risk:
   • LABAs should always be used with ICS in asthma to reduce the risk of severe exacerbations.
2. Cardiovascular Disease:
   • Use with caution in patients with arrhythmias, ischemic heart disease, or hypertension.
3. Diabetes:
   • May increase blood glucose levels; monitor in diabetics.
4. Pregnancy/Lactation:
   • Category C: Use only if benefits outweigh risks.
   • Excreted in breast milk; avoid breastfeeding.

Formoterol interacts with:

• Beta-Blockers:
  • Non-selective beta-blockers (e.g., propranolol) antagonize bronchodilatory effects.
• Diuretics:
  • Increased risk of hypokalemia with loop or thiazide diuretics.
• Xanthines (e.g., theophylline):
  • Increased risk of hypokalemia and arrhythmias.
• Corticosteroids:
  • Enhanced hypokalemic effect.
• QT-Prolonging Drugs:
  • Antiarrhythmics (e.g., amiodarone), macrolides (e.g., azithromycin) – additive risk of arrhythmias.

• Generic: Formoterol fumarate.
• Brand Names: Oxis (single agent), Symbicort (combination with budesonide), Foradil.