Charcoal hemoperfusion for theophylline overdose: case report and proposal for predicting treatment time.

Charcoal hemoperfusion is effective in the treatment of theophylline overdose. Estimation of the time required for charcoal hemoperfusion has been based on personal experience and judgment. We used pharmacokinetic data from a patient and from case reports to generate a formula for predicting treatment time. Pharmacokinetic parameters were calculated using model-independent analysis of concentration-time curves from two treatments of charcoal hemoperfusion. These values were compared with published data and incorporated into a formula that was derived from the elimination rate constant to estimate treatment time of charcoal hemoperfusion: Time (min) = (ln conci-ln concd)/0.0057, where the concentration of theophylline is in mumol/L. The formula may be valid in patients in whom the serum theophylline concentration is less than or equal to 516 mumol/L or 92 mg/L. It may be used as a guide to estimate the length of charcoal hemoperfusion in the treatment of theophylline toxicity. Its validation requires implementation and evaluation in future cases.