Effect of an oral contraceptive on the plasma levels of budesonide and prednisolone and the influence on plasma cortisol

Objective: TO investigate whether the use of an oral contraceptive would in fluence plasma levels of budesonide (Entocort capsules) or prednisolone (pl ain tablets) during repeated oral administration of these glucocorticostero ids. Plasma concentrations of cortisol and ethinyl estradiol (INN, ethinyle stradiol) were also compared. Methods: Forty healthy women took part in this single-blind, randomized pla cebo-controlled study with two parallel groups, where a three-way crossover design was applied within groups. One group was taking an oral contracepti ve (150 mu g desogestrel and 30 mu g ethinyl estradiol); the other group (c ontrol) was not. On seven consecutive mornings, oral doses of 4.5 mg budeso nide, 20 mg prednisolone, or placebo were administered. There was a washout period of at least one menstrual cycle between administration periods. Results: Ln the oral contraceptive users, the average plasma concentration of prednisolone was 131% higher than in the control group (P < .001), where as the average plasma concentration of budesonide was only 22% higher (not significant). Mean plasma cortisol levels were suppressed by 90% and 82% wi th prednisolone and by 22% and 28% with budesonide in oral contraceptive us ers and the control subjects, respectively. The group difference was signif icant with prednisolone (P < .001) but not with budesonide, Ethinyl estradi ol levels in plasma were not affected by administration of either glucocort icosteroid, Conclusion: No difference was found in plasma levels of budesonide or in co rtisol suppression after administration of budesonide capsules in women tak ing the oral contraceptive and those who were not. The oral contraceptive u sers had much higher plasma levels of prednisolone and greater cortisol sup pression. This result suggests that oral budesonide can be used with mainta ined safety in women using oral contraceptives.