QTc prolongation in patients with symptoms of cocaine use

Supervía A, Clemente C, Aguirre A, Marín M, Puente I, Echarte JL

Objetive: To assess the presence of QTc prolongation in emergency department patients

with symptoms of cocaine intoxication and to determine whether QTc prolongation

correlated with benzoylecgonine level.

Methods: The records of all patients coming to the emergency department with

symptoms of cocaine intoxication in 2009 were reviewed to collect data on age, sex,

and use of drugs that could cause QTc prolongation A QTc interval longer than 450

milliseconds was considered prolonged. Benzoylecgonine levels were also recorded. A

group of nonusers of cocaine were used as controls.

Results: Data for 44 cases and 18 controls were included. The QTc interval was

prolonged in cocaine users (445.7 milliseconds vs 411.1 milliseconds in nonusers;

P<.001). A higher percentage of cases had QTc prolongation (59.1% vs 16.7% of the controls; P=.002). Benzoylecgonine level and QTc duration were not correlated. Nine patients were in treatment with drugs that could cause QT interval changes. However, QTc duration did not differ between these patients and others who were not taking those drugs; nor were the percentages of QTc interval disturbances different between these 2 patient groups. Conclusions: Cocaine use causes QTc prolongation and is associated with more observations of pathologically prolonged intervals. The differences are not influenced by medications that also prolong the QT interval. Benzoylecgonine level and QTc duration are not correlated.

Aguirre A, Clemente C, Echarte JL, Marín M, Puente I, Supervía A