In an attempt to determine proper dose and route of the administration of aminophyline, plasma theophylline concentration was followed up in 20 asthmatics and 6 controls after aminophylline, was given by oral administration, intravenous injection, intravenous drip infusion, or by the combination of them. Plasma theophylline concentration was measured by Schack and Waxler's method. No significant differences were seen between the plasma theophylline concentrations in asthmatics and those in controls after the administration of aminophylline. The plasma theophylline reached to the highest concentration rapidly after an intravenous injecton of aminophylline, where as it reached the peak gradually in 3 to 4 hours affter intravenous infusion or oral administration of aminophylline. The peak plasma theophylline concentrations following intravenous injection, drip infusion, intravenous injection plus drip infusion and oral administration were 6.91, 3.86, 7.53, 2.87μg/ml respectively. The half-time of plasma theophylline concentrations were 3 hours after an intravenous injection of aminophylline and 6 to 9 hours after its intravenous injection plus drip infusion. The appropriate administration of aminophylline in the first day of asthma attack is considered to be 250mg by intravenous injection together with another 250mg by drip method, followed by 250mg drip infusion every 6 hours.
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