CNS Toxicity after Ingestion of Topical Lidocaine

To the Editor: Because of its extensive first-pass metabolism (70 per cent),¹ lidocaine is generally considered to be relatively inactive when taken orally. We recently encountered a case of inadvertent ingestion of oral lidocaine with resultant toxicity. A 74-year-old woman in relatively good health was admitted to the hospital for elective dilation of an esophageal stricture. Her medical history included coronary-artery disease and atrial fibrillation that had been converted to sinus rhythm by digoxin and quinidine. Laboratory studies revealed normal serum levels of creatinine and transaminase. Immediately before an endoscopic procedure, the patient was given a cup containing 30 ml.