Avacort Drug Interactions

The metabolism of budesonide is primarily mediated by CYP3A4. Inhibitors of this enzyme, e.g. ketoconazole and itraconazole, can therefore increase systemic exposure to budesonide. The combination should be avoided. If this is not possible, the period between treatments should be as long as possible and a reduction of the budesonide dose could also be considered. Other potent inhibitors of CYP3A4 are also likely to markedly increase plasma levels of budesonide.
Marked increases in plasma levels (on average four-fold) may occur if itraconazole, 200 mg once daily, is administered concomitantly with inhaled budesonide (single dose of 1000 μg).
Raised plasma concentrations of and enhanced effects of corticosteroids have been observed in women also treated with oestrogen and contraceptive steroids, but no effect has been observed with budesonide and concomitant intake of low dose combination oral contraceptives.
Because adrenal function may be suppressed, an ACTH stimulation test for diagnosing pituitary insufficiency might show false results (low values).