Cortiment Drug Interactions

No interaction studies have been performed.
Budesonide is primarily metabolized by cytochrome P450 3A4 (CYP3A4). Inhibitors of this enzyme are, e.g. ketoconazole, itraconazole, HIV protease inhibitors (including cobicistat-containing products) and grapefruit juice. Co-treatment with CYP3A inhibitors is expected to increase systemic exposure to budesonide several times and the risk of systemic side effects (see PRECAUTIONS). The combination should be avoided unless the benefit outweighs the increased risk of systemic corticosteroid side-effects, in which case patients should be monitored for systemic corticosteroid side-effects. If treatments are combined, the period between dosing of the combined treatments should be as long as possible and a reduction of the budesonide dose could also be considered. Budesonide is unlikely to inhibit other drugs metabolized via CYP3A4, since budesonide has low affinity to the enzyme.
Concomitant treatment with CYP3A4 inducers such as carbamazepine may reduce budesonide exposure, which may require a dose increase.
Corticosteroid interactions that may present a significant hazard to selected patients are those with heart glycosides (increased effect due to reduced potassium levels) and diuretics (increased elimination of potassium).
Increased plasma concentrations of and enhanced effects of corticosteroids have been observed in women also treated with oestrogens and contraceptive steroids, but no such effect has been observed with budesonide and concomitant intake of low-dose combination oral contraceptives.
Although not studied, concomitant administration of colestyramine or antacids may reduce budesonide uptake, in common with other drugs. Therefore these preparations should not be taken simultaneously, but at least two hours apart.
At recommended doses, omeprazole does not affect the pharmacokinetics of oral budesonide, whereas cimetidine has a slight but clinically insignificant effect.
Because adrenal and/or pituitary function may be suppressed, an ACTH stimulation test for diagnosing pituitary or adrenal insufficiency might show false results (low values of cortisol).