Symbicort Turbuhaler Drug Interactions

Pharmacokinetic interactions: The metabolism of budesonide is primarily mediated by the enzyme CYP3A4. Potent CYP3A4 inhibitors may therefore increase systemic exposure to budesonide. This is of limited clinical importance for short-term (1-2 weeks) treatment with potent CYP3A4 inhibitors but should be taken into consideration during long-term treatment.
If a patient requires long-term concomitant treatment with Symbicort and a potent CYP3A4 inhibitor, the benefit should be weighed against the increased risk of systemic corticosteroid side effects, patients should be monitored for corticosteroid side effects and/or a reduction of the ICS dose could be considered.
Pharmacodynamic interactions: Neither budesonide nor formoterol have been observed to interact with any other drug used in the treatment of asthma or COPD.
β-receptor blocking agents: β-receptor blocking agents, especially those that are non-selective, may partially or totally inhibit the effect of β₂-agonists. These drugs may also increase airway resistance, therefore the use of these drugs in asthma patients is not recommended.
Other sympathomimetic agents: Other β-adrenergic stimulants or sympathomimetic amines such as ephedrine should not be given concomitantly with formoterol, since the effects will be cumulative. Patients who have already received large doses of sympathomimetic amines should not be given formoterol.
Xanthine derivatives, mineralocorticosteroids and diuretics: Hypokalaemia may result from β₂-agonist therapy and may be potentiated by concomitant treatment with xanthine derivatives, mineralocorticosteroids, and diuretics (see Hypokalaemia under Precautions).
Monoamine oxidase inhibitors, tricyclic antidepressants, quinidine, disopyramide, procainamide, phenothiazines and antihistamines: The adverse cardiovascular effects of formoterol may be exacerbated by concurrent administration of drugs associated with QT interval prolongation and increased risk of ventricular arrhythmia. For this reason, caution is advised when formoterol is administered to patients already taking monoamine oxidase inhibitors, tricyclic antidepressants, quinidine, disopyramide, procainamide, phenothiazines or antihistamines associated with QT interval prolongation (eg terfenadine, astemizole).