Acute Lidocaine Toxicity: a Case Series

Introduction: Parenteral form of lidocaine is the best-known source of lidocaine poisoning. This study aimed to evaluate the characteristics of acute lidocaine toxicity. Methods: In this retrospective cross-sectional study, demographics, clinical presentation, laboratory findings, and outcome of patients intoxicated with lidocaine (based on  ICD10 codes) admitted to Loghman Hakim Hospital, during April 2007 to March 2014 were analyzed. Results: 30 cases with the mean age of 21.83 ± 6.57 year were studied (60% male). All subjects had used either 6.5% lidocaine spray or 2% topical formulations of lidocaine. The mean consumed dose of lidocaine was 465 ± 318.17 milligrams. The most frequent clinical presentations were nausea and vomiting (50%), seizure (33.3%), and loss of consciousness (16.7%). 22 (73.3%) cases had normal sinus rhythm, 4 (13.3%) bradycardia, 2 (6.7%) ventricular tachycardia, and 2 (6.7%) had left axis deviation. 11 (36.6%) cases were intubated and admitted to intensive care unit (ICU) for 6.91 ± 7.16 days. Three patients experienced status epilepticus that led to cardiac arrest, and death (all cases with suicidal intention). Conclusion: Based on the results of this study, most cases of topical lidocaine toxicity were among < 40-year-old patients with a male to female ratio of 1.2, with suicidal attempt in 90%, need for intensive care in 36.6%, and  mortality rate of 10%.