Budesonide × fluvoxamine

Fluvoxamine is a CYP3A4 inhibitor; budesonide is a CYP3A4 substrate. Oral budesonide AUC may rise, increasing hypercortisolism risk in long-term therapy. Inhaled budesonide is minimally absorbed — the effect is weaker.

On long-term therapy: moon face, weight gain with fat redistribution, skin thinning, acne, muscle weakness, mood disturbance, hyperglycaemia.

For inhaled budesonide and fluvoxamine, no adjustment needed. On oral budesonide over 8 weeks, assess for hypercortisolism and consider antidepressant alternatives — sertraline or escitalopram (minimal CYP3A4 effect).