Potentially toxic serum lidocaine concentrations following spray anesthesia for bronchoscopy

Abstract

Serum lidocaine concentrations were measured in a series of ten patients during and after topical lidocaine spray anesthesia used for diagnostic fiberoptic bronchoscopy. Mean total dose of lidocaine ranged from 480-720 mg. Peak serum lidocaine concentrations averaged 3.6 micrograms/ml (range: 1.9 to 7.4 micrograms/ml), and were attained shortly after the start of the procedure. Repeated topical administration of lidocaine spray therefore may lead to large cumulative doses and serum concentrations which are in the therapeutic or potentially toxic range.

Pharmacokinetics of Lidocaine and Its Metabolites Following Vaginal Administration of Lidocaine Gel to Healthy Female Subjects

“…It is absorbed orally, although its bioavailability is limited due to first‐pass metabolism . When administered at relatively high doses, intrabronchial lidocaine administration results in therapeutic serum concentrations when the drug is retained for sufficient time to allow absorption to occur . Variable and incomplete absorption was observed following an intranasal gel formulation .…”

“…Work by Lebedzki and colleagues demonstrated that administration of a 10% lidocaine spray solution followed by 2% to 4% liquid lidocaine doses (total doses of 480 to 720 mg) for anesthesia of the pharynx, larynx, trachea, and bronchi in patients undergoing bronchoscopy had peak mean serum concentrations of 3.6 µg/mL (range 1.9 to 7.4 µg/mL) observed within an hour of the start of diagnostic bronchoscopy procedures. 4 In subsequent work, lidocaine systemic exposure administered by high-frequency nebulization was compared to spray administration to the trachea and bronchi. Nebulized lidocaine into the pulmonary vasculature resulted in approximately 60% lower lidocaine peak serum concentrations compared with the spray administration (mean concentrations; 1.4 vs 3.6 µg/mL, respectively).…”

“…However, repeated administration of topical sprays can potentially lead to large cumulative doses and serum concentrations. Work by Lebedzki and colleagues demonstrated that administration of a 10% lidocaine spray solution followed by 2% to 4% liquid lidocaine doses (total doses of 480 to 720 mg) for anesthesia of the pharynx, larynx, trachea, and bronchi in patients undergoing bronchoscopy had peak mean serum concentrations of 3.6 µg/mL (range 1.9 to 7.4 µg/mL) observed within an hour of the start of diagnostic bronchoscopy procedures . In subsequent work, lidocaine systemic exposure administered by high‐frequency nebulization was compared to spray administration to the trachea and bronchi.…”

Physicochemical studies on local anaesthetic loaded second generation nanolipid carriers

“…38,42 While considering the aforementioned dermal applications, it is one of the essential condition that the drug should preferably remain on the skin surface, thus minimizing its side effects. 45 Studies demonstrated by different researchers 24,38,40 suggest that the severe side effects can drastically be reduced when loaded in suitable drug delivery system. 38 In spite of a number of available reports on local anaesthetics loaded drug delivery systems, however, no such single system have been found to be completely prudent in terms of topical applications.…”

Lidocaine not so innocent: Cardiotoxicity after topical anaesthesia for bronchoscopy

“…The mean total dose of lidocaine of 480–720 mg led to concentrations between 1.9 and 7.4 μg/ml. [3] Repeated doses may therefore easily induce toxic levels. Day et al .…”