American journal of therapeutics
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An initial carbamazepine concentration may initially be supratherapeutic, therapeutic, or even subtherapeutic only to persist to rise over time. The aim of this study was to report the frequency of toxic carbamazepine concentrations continuing to rise and to estimate how often an initially therapeutic or subtherapeutic concentration misrepresents the potential toxicity of an acute carbamazepine overdose. An 8-year retrospective search of all carbamazepine exposures reported to the Illinois Poison Center (January 1, 2001 through December 31, 2008) was reviewed. ⋯ Additionally, several patients with initial levels of therapeutic or subtherapeutic concentration later became comatose and required ventilator management. Initial serum carbamazepine concentrations can be misleading. Serial measurements documenting a declining carbamazepine concentration or prolonged observation are recommended when managing these overdoses.