Search

Objective: To investigate whether the use of an oral contraceptive would influence plasma levels of budesonide (Entocort capsules) or prednisolone (plain tablets) during repeated oral administration of these glucocorticosteroids. Plasma concentrations of cortisol and ethinyl estradiol (INN, ethinylestradiol) were also compared., Methods: Forty healthy women took part in this single-blind, randomized placebo-controlled study with two parallel groups, where a three-way crossover design was applied within groups. One group was taking an oral contraceptive (150 microg desogestrel and 30 microg ethinyl estradiol); the other group (control) was not. On seven consecutive mornings, oral doses of 4.5 mg budesonide, 20 mg prednisolone, or placebo were administered. There was a washout period of at least one menstrual cycle between administration periods., Results: In the oral contraceptive users, the average plasma concentration of prednisolone was 131% higher than in the control group (P < .001), whereas the average plasma concentration of budesonide was only 22% higher (not significant). Mean plasma cortisol levels were suppressed by 90% and 82% with prednisolone and by 22% and 28% with budesonide in oral contraceptive users and the control subjects, respectively. The group difference was significant with prednisolone (P < .001) but not with budesonide. Ethinyl estradiol levels in plasma were not affected by administration of either glucocorticosteroid., Conclusion: No difference was found in plasma levels of budesonide or in cortisol suppression after administration of budesonide capsules in women taking the oral contraceptive and those who were not. The oral contraceptive users had much higher plasma levels of prednisolone and greater cortisol suppression. This result suggests that oral budesonide can be used with maintained safety in women using oral contraceptives.

In 11 patients, in whom a lung lobe or whole lung was to be resected, a single dose of 1.6 mg inhaled budesonide was given pre-operatively. In 9 of them, concentrations of the drug in both lung tissue and blood plasma were measured. Budesonide concentrations in lung tissue, at least 90 min after dosage, were 2.1-8.9 nmol kg-1. Concentrations in blood plasma (0.27-1.1 nmol kg-1) were 1/8th of those in lung tissue.

Budesonide is a potent nonhalogenated glucocorticoid consisting of a 1/1 mixture of the two epimers 22R and 22S. The kinetics of these epimers were studied in six healthy male subjects after intravenous administration of 500 micrograms 3H-budesonide. Estimation of the epimer concentrations in plasma was made possible by development of an HPLC method for simultaneous separation and quantification. The plasma t 1/2, distribution volume (V beta), and plasma clearance for epimer 22R were (mean +/- SD) 2.66 +/- 0.57 hr, 425 +/- 100 l, and 117 +/- 40 l/hr. The corresponding values for epimer 22S were 2.71 +/- 0.69 hr, 245 +/- 38 l, and 67 +/- 19 l/hr. Differences in V beta and plasma clearance between the two were significant. The larger V beta noted for epimer 22R may be a result of higher tissue affinity. The high plasma clearance for both epimers should largely reflect their high rate of liver biotransformation.