This Article Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via Google Scholar Google Scholar Articles by YASUDA, K. Articles by MIURA, K. Search for Related Content PubMed PubMed Citation Articles by YASUDA, K. Articles by MIURA, K.

Changes in the Pharmacokinetics of Plasma Total and Free Prednisolone during Daily and Intermittent Regimens^*

Third Department of Internal Medicine, Gifu University School of Medicine Gifu, Japan

Address requests for reprints to: Dr. Keigo Yasuda, M.D., Third Department of Internal Medicine, 40 Tsukasa-machi, Gifu MZ 500, Japan.

To determine the pharmacokinetic changes of prednisolone associated with differing therapy regimens, we studied 15 patients with various diseases who were treated with daily doses of prednisolone and were then placed on an intermittent regimen, [administration for 4 consecutive days (on-day period), followed by 3 days cessation (off-day period)]. The mean duration of the study and the mean total dosage were 1.6 months and 2.4 g in the daily period, respectively, and 4.7 months and 3.5 g in the intermittent period, respectively. Blood was drawn for 6 h after iv administration of 20 mg prednisolone (average, 0.36 mg/kg). Plasma total and free prednisolone concentrations were measured by RIA. On-day and off-day tests were performed during the same week. The mean MCR of both total and free prednisolone decreased significantly in the daily and on-day periods compared with the pretreatment values. The decreased MCR during the on-day period was restored to the pretreatment level during the off-day period. A similar trend was observed in the changes in half-life, prolongation in the daily and on-day periods compared with the pretreatment value, and restoration to the pretreatment level during the off-day period. These alterations were not associated with the total duration or the total dosage of prednisolone administered.

The results indicate that the pharmacokinetic parameters of prednisolone may periodically change during the intermittent regimen, and that off-day and on-day parameters are similar to those before therapy and during the daily period, respectively.

^* This work was supported in part by grants from the Ministry of Health and Welfare. Disorders of the Hypothalamo-Pituitary gland, 1986–1987, and Disorders of the Adrenal Gland, 1986–1987, Japan. Presented in part at the 70th Annual Meeting of The Endocrine Society, New Orleans, LA, June 1988.

Received March 10, 1989.