Pharmacokinetics and rectal bioavailability of hydrocortisone acetate after single and multiple administration in healthy subjects and patients.

The pharmacokinetics and bioavailability of hydrocortisone after rectal administration of a hydrocortisone acetate foam were determined after single and multiple dosing in healthy subjects as well as in patients with inflammatory bowel disease. Endogenous hydrocortisone was suppressed by dexamethasone administration. Plasma levels were compared with those observed after intravenous administration of hydrocortisone. Only a very small part of the rectal dose (100 mg) was absorbed; the mean absolute bioavailability was 3.1% in healthy volunteers and 4.5% in patients. There was substantial intersubject variability. Although maximum hydrocortisone levels after single or multiple doses were significantly higher (about 70%) in the patient group, the systemic bioavailability is very low so that the risk of systemic side effects after rectal administration of hydrocortisone acetate foam has to be considered very low.