What type of medication is Symbicort (budesonide/formoterol)?

Symbicort: Combination ICS/LABA Medication

Symbicort (budesonide/formoterol) is a fixed-dose combination inhaler containing an inhaled corticosteroid (budesonide) and a long-acting beta2-agonist (formoterol) used for maintenance treatment of asthma and COPD. 1, 2

Medication Components

• Budesonide is an inhaled corticosteroid that provides anti-inflammatory effects by reducing airway inflammation 3, 2
• Formoterol is a long-acting beta2-adrenergic receptor agonist (LABA) that acts as a bronchodilator, relaxing bronchial smooth muscle through stimulation of beta2-receptors 4
• The combination delivers both components through a single inhaler device (available as Turbuhaler dry powder inhaler or pressurized metered-dose inhaler) 5, 6

Mechanism of Action

• Formoterol provides bronchodilation by stimulating intracellular adenyl cyclase, which increases cyclic AMP levels, causing relaxation of bronchial smooth muscle and inhibiting release of inflammatory mediators from mast cells 4
• Formoterol has more than 200-fold greater activity at beta2-receptors compared to beta1-receptors, providing selective bronchodilation 4
• Budesonide provides the corticosteroid anti-inflammatory component necessary for long-term asthma control 3
• The combination demonstrates synergistic effects when both drugs are administered via one inhaler, though mechanisms are not fully understood 2

Clinical Indications

• For asthma: The American College of Allergy, Asthma, and Immunology endorses budesonide/formoterol for maintenance therapy in patients with persistent asthma not adequately controlled on inhaled corticosteroids alone 1
• For COPD: The American Thoracic Society recommends budesonide/formoterol combination inhalers for COPD patients with severe disease, frequent exacerbations (≥2 per year), or persistent symptoms despite single bronchodilator therapy 7
• The Global Initiative for Chronic Obstructive Lung Disease (GOLD) recommends initiating ICS/LABA therapy in patients with FEV1 <50-60% predicted and ≥2 exacerbations per year 7

Unique Features of Budesonide/Formoterol

• Rapid onset of action: Formoterol provides bronchodilation within 1 minute of treatment, allowing budesonide/formoterol to function as both controller and reliever medication 2, 8
• SMART protocol: The American College of Allergy, Asthma, and Immunology endorses the Single Maintenance and Reliever Therapy (SMART) approach using budesonide/formoterol for both daily maintenance and as-needed relief of breakthrough symptoms 1
• Lower corticosteroid exposure: Budesonide/formoterol delivers a lower total daily corticosteroid dose compared to fluticasone/salmeterol, which may be advantageous for minimizing corticosteroid-related adverse effects 7

Clinical Efficacy

• In 12-month trials of COPD patients, budesonide/formoterol 320/9 mcg twice daily produced significantly higher FEV1 and peak expiratory flow compared to budesonide alone or placebo 5, 9
• The combination significantly reduced COPD exacerbation rates and prolonged time to first exacerbation compared to formoterol alone and placebo 9
• In asthma trials, budesonide/formoterol demonstrated greater efficacy than inhaled corticosteroids alone and at least equivalent efficacy to both monocomponents administered in separate inhalers 2, 6

Critical Safety Considerations

• Never use LABAs as monotherapy: The American Academy of Family Physicians warns that LABA monotherapy without an inhaled corticosteroid increases risk of asthma-related death and hospitalization 1
• Pneumonia risk in COPD: The American College of Chest Physicians notes that ICS-containing regimens increase pneumonia risk by approximately 4% in COPD patients 7
• Common adverse effects include skeletal muscle tremor, tachycardia, decreases in plasma potassium (mean reduction 0.68 mEq/L at high doses), and increases in plasma glucose 4

Available Formulations

• Budesonide/formoterol is available in multiple dose strengths: 80/4.5 mcg, 160/4.5 mcg, and 320/9 mcg per inhalation 2, 6
• For mild-to-moderate persistent asthma, the American Academy of Family Physicians recommends starting with 80/4.5 mcg, 2 inhalations twice daily 1
• For moderate to severe persistent asthma, 160/4.5 mcg x 2 inhalations (320/9 mcg) twice daily is recommended 6