Comparison of prednisolone kinetics in patients receiving daily or alternate-day prednisone for asthma.

Prednisolone pharmacokinetics were compared in seven patients with asthma managed by alternate-day prednisone therapy and in seven patients with asthma requiring daily doses of prednisone. Steroid requirements of these patients were carefully characterized and had been stable for at least 12 months. Prednisolone volume of distribution, elimination clearance, and elimination t1/2 averaged 0.606 +/- 0.061 and 0.553 +/- 0.162 L/kg, 2.28 +/- 0.43 and 1.93 +/- 0.54 ml/min/kg, and 204 +/- 44 and 214 +/- 19 minutes in patients receiving alternate-day or daily prednisone therapy, respectively. These results indicate that differences in these pharmacokinetic parameters do not account for the well-established clinical observation that some patients require daily prednisone doses and that their disease cannot be managed with alternate-day steroid therapy.