Pharmacokinetics and absolute rectal bioavailability of hydrocortisone acetate in distal colitis

The hydrocortisone pharmacokinetic profiles of hydrocortisone acetate foam (Proctocort) administered rectally was assessed in healthy volunteers and patients with ulcerative colitis or X-irradiation colitis. Endogenous production of hydrocortisone was suppressed by dexamethasone. Comparison of these data with those obtained after intravenous administration enabled assessment of absolute bioavailability, which was 30.0 +/- 15.1% in healthy volunteers vs. 16.4 +/- 14.8% in patients (P = 0.09). Maximal concentrations of hydrocortisone were also decreased in patients, 277 +/- 215 nmol/L vs. 610 +/- 334 nmol/L (P = 0.03). There was a nonsignificant tendency to faster absorption of hydrocortisone in patients vs. healthy volunteers, as the times to peak concentration were, respectively, 2.5 +/- 1.2 h vs. 2.8 +/- 0.8 h (P = 0.64), and the mean absorption times were 1.96 +/- 1.45 h vs. 2.54 +/- 1.62 h (P = 0.46). Thus, rectal inflammation resulted in a lower absorption of hydrocortisone. In addition systemic plasma levels remained in the physiological range, so that only minor side effects are to be expected.