Model for theophylline overdose treatment with oral activated charcoal

Abstract

The effect of repeated oral doses of activated charcoal on theophylline kinetics was studied in 6 subjects with hepatic cirrhosis and 5 patients with moderate theophylline poisoning to determine whether an activated charcoal regimen would be a useful strategy in patients with theophylline poisoning who did not require hemoperfusion. Six subjects with cirrhosis were injected i.v. with 6 mg/kg aminophylline followed by either water or water with activated charcoal (140 g) in divided doses over 12 h. In these subjects, treatment with activated charcoal decreased the mean (.+-. SE) serum theophylline t1/2 [half-life] from 12.7 .+-. 4.0 h to 4.0 .+-. 0.7 h. Subjects with the longest control t1/2 demonstrated the greatest charcoal effect. A mathematical model was developed that predicts that treatment with repeated oral doses of activated charcoal would result in an averge serum theophylline t1/2 of 7.1 h or less even if the subject''s endogenous theophylline t1/2 is very long. In a pilot study of 5 patients with moderate theophylline poisoning, treatment with repeated oral doses of activated charcoal was well tolerated and led to a mean (.+-. SE) t1/2 that was shorter than expected (4.9 = 0.8 h, range 3.1-7.1 h). Evidently, repeated oral doses of activated charcoal are relatively more effective in decreasing the serum theophylline t1/2 in persons with long endogenous t1/2 and this may be useful for certain patients with mild or moderate theophylline poisoning.