Rational Intravenous Doses of Theophylline

Abstract

Physiologic responses to intravenously administered theophylline were determined in nine hospitalized asthmatic subjects. In each patient incremental theophylline plasma concentration plateaus were attained at which pulmonary-function changes related to drug administration were examined. Continuous improvement in vital capacity and first-second forced expiratory volume was observed over the plasma range of theophylline concentration of 5 to 20 mg per liter. The improvement varied directly with the logarithm of the plasma concentration. A safe and effective dosage regimen for intravenous theophylline can be based on these observations. After a loading dose of aminophylline, 5.6 mg per kilogram given intravenously, 0.9 mg per kilogram per hour can be given as a maintenance dose. This amount will result in a plasma theophylline concentration of approximately 10 mg per liter for 95 per cent of patients and in recovery from some 30 to 40 per cent of reversible pulmonary-airway obstruction. (N Engl J Med 289:600–603, 1973)