Excessive doses of lidocaine products or short intervals between doses can result in high plasma levels & serious adverse effects. Presence of sepsis or severely traumatized mucosa in area of application. Oropharyngeal use has increased risk of aspiration. When used for endotracheal tube lubrication, avoid introducing into lumen of the tube. Closely supervise patients being treated w/ class III antiarrhythmic drugs eg, amiodarone & monitor ECG due to additive effects. Patients w/ partial or complete heart block, elderly & patients in poor general health. Porphyric patients. Advanced liver disease or severe renal function. Pregnancy & lactation.