Model for theophylline overdose treatment with oral activated charcoal

The effect of repeated oral doses of activated charcoal on theophylline kinetics was studied in six subjects with hepatic cirrhosis and five 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 IV with 6 mg/kg aminophylline followed by either water or water with activated charcoal (140 gm) in divided doses over 12 hr. In these subjects, treatment with activated charcoal decreased the mean (±SE) serum theophylline t½ from 12.7 ±4.0 hr to 4.0 ±0.7 hr. Subjects with the longest control t½s demonstrated the greatest charcoal effect. We developed a mathematical model that predicts that treatment with repeated oral doses of activated charcoal would result in an average serum theophylline t½ of 7.1 hr or less even if the subject's endogenous theophylline t½ is very long. In a pilot study of five patients with moderate theophylline poisoning, treatment with repeated oral doses of activated charcoal was well tolerated and led to a mean (±SE) t½ that was shorter than expected (4.9 ± 0.8 hr, range 3.1 to 7.1 hr). We conclude that repeated oral doses of activated charcoal are relatively more effective in decreasing the serum theophylline t½ in persons with long endogenous t½s and that this may be useful for certain patients with mild or moderate theophylline poisoning. Clinical Pharmacology and Therapeutics (1984) 35, 402–408; doi: 10.1038/clpt.1984.50