Lidocaine vs Parabens as Convulsants

Abstract

To the Editor:— In a recent letter to the editor (205:803, 1968) Richard S. Crampton, MD, intimated that the methylparaben present in the lidocaine hydrochloride preparation (Xylocaine, Astra 1%), used to control ventricular tachycardia, was a causative agent in convulsions and respiratory arrest. The source article for this intimation, by Schorr (204:859, 1968), refers toallergicreactions with thep-hydroxybenzoate family of bacteriostatic and fungistatic agents (administeredtopically) and would appear to have little bearing on the toxic reactions described. Matthews et al1in studying the acute and chronic toxic reactions ofp-hydroxybenzoic acid esters on dogs, rats, and mice revealed that the lethal dose (LD)50of methylparaben, as the sodium salt, given intravenously to mice was 170 ±8.4 mg/kg. In dogs, the fatal intravenous dose of methylparaben was 940 mg/kg, when injected at 20 mg/kg/min, and 80 mg/kg at a rate of 40