Laudanosine and atracurium concentrations in a patient receiving long-term atracurium infusion.

OBJECTIVE

Atracurium is sometimes used for muscle relaxation in patients undergoing mechanical ventilation. Use of atracurium in high doses or for a long period of time has raised the possibility of the accumulation of laudanosine, a breakdown product known to cause seizure activity in animals. The objective of this report was to see if laudanosine accumulation and seizure activity had occurred in a patient who had received a long-term, relatively high-dose infusion of atracurium.

DESIGN

Case report. The patient received atracurium for 38 days, at rates ranging from 0.3 to 0.96 mg/kg/hr. An electroencephalogram (EEG) was done before the discontinuation of the infusion, and plasma concentrations of atracurium and laudanosine were measured at, and after, the termination of the atracurium infusion. The laudanosine elimination half-life was calculated.

SETTING

Intensive care unit.

PATIENT

A 23-yr-old woman admitted with sickle cell crisis, complicated by acute chest syndrome, acute respiratory distress syndrome, and hepatic and renal failure.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

As expected, laudanosine concentrations were increased but were below the level reported to cause seizure activity in animals. Laudanosine elimination half-life was prolonged to 617 mins, which was consistent with previously reported values. The patient's EEG was normal, with no ictal pattern.

CONCLUSIONS

Despite long-term use of high doses of atracurium infusion and the increased elimination half-life of laudanosine, only moderate accumulation of laudanosine occurred, and the EEG was normal. Hence, it appears unlikely that toxic concentrations of laudanosine would be reached, even in a critically ill patient.