Intravenous lidocaine as a suppressant of persistent cough caused by bronchoscopy

The effect of intravenous lidocaine in the treatment of persistent cough occurring after diagnostic bronchoscopies performed under general anaesthesia was investigated in a controlled clinical trial. The study comprised 28 adults patients, all of whom had regained consciousness after anaesthesia. Fifteen patients were treated with lidocaine (1.05 mg/kg body weight) and 13 patients with placebo (saline). In each patient the intravenously injected dose was repeated once after 5 min. In 11 of the 15 patients (73%) who received lidocaine coughing ceased, while it continued in all 13 patients in the placebo group. The difference is highly significant (P less than 0.001). None of the patients developed side effects such as hypotension, arrhythmias, central nervous system symptoms or respiratory depression after injection of lidocaine. It is therefore concluded that intravenous lidocaine in man is a safe and useful cough-suppressant.