Presentation and Status in Health Basket
As with any local anaesthetic, the safety and effectiveness of lidocaine depends on the proper dosage, the correct technique, adequate precautions and readiness for emergencies.
The following dosage recommendations should be regarded as a guide. The
clinician’s experience and knowledge of the patient’s physical status are of
importance in calculating the required dose.
The degree of absorption from mucous membranes is variable but especially high from the bronchial tree. Application only to areas below the vocal cords may result in excessive plasma concentrations because of less transfer to the intestine and less first-pass loss.
Each actuation of the metered-dose valve delivers 10mg Lidocaine base. It is
unnecessary to dry the site prior to application.
Xylocaine Pump Spray 10% should not be used on cuffs of endotracheal tubes
(ETT) made of plastic.
– Otorhinolaryngology: 3 metered doses for puncture of the maxillary sinus or
other minor surgical procedures.
– Obstetrics – During delivery: Up to 20 metered doses (200mg lidocaine base).
– Introduction of instruments, tubes and catheters into the respiratory and
digestive tract: Up to 20 metered doses (200mg lidocaine base) for procedures in pharynx, larynx and trachea. During prolonged procedures up to 400 mg of lidocaine may be administered. In addition, when combined with other lidocaine products, the total dose should not exceed 400 mg.
With application mainly to the larynx, trachea and bronchi, the dose should
not exceed 20 metered doses (200 mg lidocaine base).
– Dental practice: 1-5 metered doses to the mucous membranes.
Debilitated or elderly patients, children over 12 years of age, acutely ill patients or patients with sepsis should be given doses commensurate with their age, weight and physical condition.
In children less than 12 years of age the dose should not exceed 3 mg/kg (e.g. 6
metered doses in an infant weighing 20 kg). When used mainly in the larynx and
trachea the dose should be reduced to 1.5 mg/kg. In children less than 3 years of age less concentrated lidocaine solutions are recommended.
Surface anaesthesia in dental practice otorhinolaryngology, obstetric and
Known history of hypersensitivity to local anaesthetics of the amide type or to
other components of the spray solution.
Excessive dosage or short intervals between doses may result in high plasma
levels and serious adverse effects. Absorption from mucous membranes is variable but is especially high from the bronchial tree. Such applications may therefore result in rapidly rising or excessive plasma concentrations with an increased risk of toxic symptoms, such as convulsions. Xylocaine Pump Spray 10% should be used with caution in patients with wounds or traumatized mucosa in the region of the proposed application. A damaged mucosa will permit increased systemic absorption. The management of serious adverse reactions may require the use of resuscitative equipment, oxygen and other resuscitative drugs.
In paralysed patients under general anaesthesia, higher blood concentrations may occur than in spontaneously breathing patients. Unparalysed patients are more likely to swallow large proportions of the dose which then undergoes considerable first pass hepatic metabolism following absorption from the gut.
The oropharyngeal use of topical anaesthetic agents may interfere with swallowing and thus enhance the danger of aspiration. This is particularly important in children because of their frequency of eating.
Numbness of the tongue or buccal mucosa may increase the danger of biting
If the dose or site of administration is likely to result in high blood levels, lidocaine, in common with other local anaesthetic, should be used with caution in the following patients who require special attention to prevent potentially
dangerous side effects:
– Patients with epilepsy.
– Patients with cardiovascular disease, heart failure.
– Patients with impaired cardiac conduction or bradycardia.
– Patients with severe renal dysfunction.
– Patients with impaired hepatic function. .
– Patients in severe shock.
– The elderly and patients in poor general health.
Avoid contact with eyes.
Patients treated with anti-arrhythmic drugs class III (e.g. amiodarone) should be under close surveillance and ECG monitoring considered, since cardiac effects may be additive.
Xylocaine Pump Spray 10% should not be used on cuffs of endotracheal tubes (ETT) made of plastic. Lidocaine base in contact with both PVC and non-PVC cuffs of endotracheal tubes may cause damage of the cuff. This damage is described as pinholes, which may cause leakage that could lead to pressure loss in the cuff.
Xylocaine Pump Spray 10% is probably porphyrinogenic and should only be prescribed to patients with acute porphyria on strong or urgent indications.
Appropriate precautions should be taken for all porphyric patients.
Allergic reaction: In extremely rare cases amide-type local anaesthetic preparations have been associated with allergic reaction (in the most severe instances anaphylactic shock).
Local reactions: Local irritations at the application site have been described. Following application to laryngeal mucosa before endotracheal intubation, reversible symptoms such as “sore throat”, “hoarseness” and “loss of voice” have been reported. The use of Xylocaine Pump Spray 10% provides surface anaesthesia during endotracheal procedure but does not prevent post-intubation soreness.
Acute systemic toxicity: Systemic adverse reactions are rare and may result from high plasma levels due to excessive dosage or rapid absorption (e.g. following application to areas below the vocal cords), or from hypersensitivity, idiosyncrasy or reduced tolerance on the part of the patient. Such reactions involve the central nervous system and/or the cardiovascular system.
CNS reactions are excitatory and/or depressant and may be characterised by
nervousness, dizziness, convulsions, unconsciousness and possibly respiratory
arrest. The excitatory reactions may be very brief or may not occur at all, in which case the first manifestations of toxicity may be drowsiness, merging into
unconsciousness and respiratory arrest.
Cardiovascular reactions are depressant and may be characterised by hypotension, myocardial depression, bradycardia and possibly cardiac arrest.
Lidocaine should be used with caution in patients receiving other local
anaesthetics or agents structurally related to amide-type local anaesthetics, e.g. antiarrhythmics such as mexiletin and tocainide, since the toxic effects are
Specific interaction studies with lidocaine and anti-arrhythmic drugs class III (e.g. amiodarone) have not been performed, but caution is advised.
Drugs that reduce the clearance of lidocaine (e.g. cimetidine or betablockers) may cause potentially toxic plasma concentrations when lidocaine is given in repeated high doses over a long time period. Such interactions should therefore be of no clinical importance following short-term treatment with lidocaine (e.g. Xylocaine Pump Spray 10%) at recommended doses.
Pregnancy and Lactation
Pregnancy: There is no, or inadequate evidence of safety of the drug in human pregnancy, but it has been in wide use for many years without apparent ill consequence and animal studies have shown to hazard. If drug therapy is needed in pregnancy, this drug can be used if there is no safer alternative.
Lactation: Lidocaine enters the mother’s milk, but in such small quantities that there is generally no risk of the child being affected at therapeutic dose levels.
Acute systemic toxicity: Toxic reactions originate mainly in the central nervous system and the cardiovascular system.
Central nervous system toxicity is a graded response with symptoms and signs of escalating severity. The first symptoms are circumoral paraesthesia, numbness of the tongue, light-headedness, hyperacusis and tinnitus. Visual disturbances and muscular tremors are more serious and precede the onset of generalized convulsions. Unconsciousness and grand mal convulsions may follow, which may last for a few seconds to several minutes. Hypoxia and hypercarbia occur rapidly following convulsions due to the increased muscular activity together with the interference with normal respiration. In severe cases,apnoea may occur. Acidosis increases the toxic effects of local anaesthetic.
Cardiovascular effects are only seen in cases with high systematic concentrations.
Severe hypotension, bradycardia, arrhythmia and cardiovascular collapse may be the result in such cases.
Cardiovascular toxic effects are generally preceded by signs of toxicity in the central nervous system, unless the patient is receiving a general anaesthetic or is heavily sedated with drugs such as benzodiazepine or barbiturate.
Recovery is due to redistribution and metabolism of the local anaesthetic drug from the central nervous system. Recovery may be rapid unless large amounts of the drug have been administered.
Treatment of acute toxicity: Treatment of acute toxicity should be instituted at the latest when twitches occur.
The necessary drugs and equipment should be immediately available. The objectives of treatment are to maintain oxygenation, stop the convulsions and support the circulation. Oxygen must be given and, if necessary, assisted ventilation (mask and bag).
An anticonvulsant should be given i.v if the convulsions do not stop spontaneously in 15-30 sec. Thiopentone sodium 1-3 mg/kg i.v. will abort the convulsions rapidly. Alternatively diazepam 0.1 mg/kg body-weight i.v. may be used although its action will be slower.
Prolonged convulsions may jeopardise the patient’s ventilation and oxygenation. If so, injection of a muscle relaxant (e.g. succinylcholine 1 mg/kg body-weight) will facilitate ventilation and oxygenation can be controlled. Early endotracheal
intubation must be considered in such situations.
If cardiovascular depression is evident (hypotension, bradycardia), ephedrine 5-10 mg i.v. should be given and repeated if necessary, after 2-3 minutes.
Should circulatory arrest occur, immediate cardiopulmonary resuscitation
should be instituted. Optimal oxygenation and ventilation and circulatory support as well as treatment of acidosis are of vital importance, since hypoxia and acidosis will increase the systemic toxicity of local anaesthetics.
Children should be given doses commensurate with their age and weight.