The oral, once-daily phosphodiesterase 4 inhibitor roflumilast lacks relevant pharmacokinetic interactions with inhaled budesonide.

This open-label, randomized, 3-period crossover study evaluated the pharmacokinetic interaction potential of roflumilast and budesonide following repeated coadministration to healthy male subjects (N = 12). Treatments consisted of oral roflumilast 500 mug, once daily, orally inhaled budesonide 800 mug, twice daily, and concomitant administration of both treatments for 7 days each. Roflumilast and roflumilast N-oxide in plasma and budesonide serum levels were measured by specific assays. Geometric mean test/reference ratios of steady-state pharmacokinetic parameters were evaluated by analysis of variance. Safety and tolerability were monitored. Pharmacokinetic parameters of roflumilast, roflumilast N-oxide, and budesonide after coadministration of roflumilast and budesonide were similar to those after mono-treatment. Compared with budesonide and roflumilast mono-treatments, slightly lower maximum serum/plasma concentration (C(max)) and area under the curve (AUC) values of roflumilast N-oxide and budesonide (ranging from -8% to -16%) were observed with combined treatment. All test/reference ratios were within predefined equivalence acceptance ranges for roflumilast AUC (0.80, 1.25) and C(max) (0.70, 1.43) and for roflumilast N-oxide and budesonide AUC and C(max) (all 0.67, 1.50). Coadministration of roflumilast and budesonide did not alter the steady-state disposition of each other and did not affect safety and tolerability of either drug.