Pharmacokinetics of intravenous methylprednisolone and oral prednisone in paediatric patients with inflammatory bowel disease during the acute phase and in remission

Objective: The present study was undertaken to evaluate the influence of inflammatory bowel disease on the pharmacokinetics of intravenous methylprednisolone and prednisolone (after oral administration of prednisone). Patients: Twelve children with inflammatory bowel disease, aged 12.3 years were studied during the active phase and in remission. In 6 patients the disease responded to oral prednisone while 6 did not respond. Methods: During the acute phase, intravenous methylprednisolone (2 mg · kg⁻¹) and oral prednisone (2 mg · kg⁻¹) were administered in a random order and blood was sampled over 48 h. Prednisone (2 mg · kg⁻¹) was readministered after remission. The concentrations of methylprednisolone and prednisolone were measured by high-pressure liquid chromatography. Results: During the acute phase, the systemic clearance of methylprednisolone was 0.98 (1 kg⁻¹ · h⁻¹) and the elimination half-life was 1.67 h. The area under the plasma concentration-versus-time curve of prednisolone was 4.00 and 3.20 · mg · h · l⁻¹ respectively during the active disease and remission, while its elimination half-life was 3.51 h during the acute phase and 2.42 h in remission. There were no pharmacokinetic differences between the patients who responded or did not respond to oral treatment. Conclusion: In children with inflammatory bowel disease, the initial response to corticosteroid therapy was not influenced by the pharmacokinetics of prednisolone and methylprednisolone. In addition, the pharmacokinetics of prednisolone was not modified by the inflammatory syndrome. Received: 5 December 1997 / Accepted in revised form: 14 April 1998