Lignocaine aerosol and persistent cough

Four patients with intractable cough improved for periods of between one and six weeks after treatment with 400 mg of lignocaine by aerosol spray. Suprisingly the lignocaine increased airways resistance in some of them. It is suggested that the excessive cough is due to excessive sensitivity of tracheal cough or irritant receptors, secondary to mucosal damage. The dangers of lignocaine inhalation are referred to.