Drug Class Description

Drug Description

Presentation

Indications

Adult Dosage

Adults and children above 12 years of age

The dosage is adjusted according to the response of the patient and the site of administration. The lowest concentration and smallest dose producing the required effect should be given. The maximum single dose of Xylocaine when given with adrenaline is 500 mg.

The following table is a guide for the more commonly used techniques in the average adult. The figures reflect the expected average dose range needed. Standard textbooks should be consulted for factors affecting specific block techniques and for individual patient requirements.

The clinician's experience and knowledge of the patient's physical status are of importance in calculating the required dose. Elderly or debilitated patients require smaller doses, commensurate with age and physical status.

Please note: Preservative containing solutions i.e. those supplied in multidose vials should not be used for intrathecal and epidural anaesthesia or in doses more than 15 ml for other types of blockades.

In general, surgical anaesthesia requires the use of higher concentrations and doses. When a less intense block is required, the use of a lower concentration is indicated. The volume of drug used will affect the extent and spread of anaesthesia.

Care should be taken to prevent acute toxic reactions by avoiding intravascular injection. Careful aspiration before and during the injection is recommended. An accidental intravascular injection may be recognised by a temporary increase in heart rate. The main dose, should be injected slowly, at a rate of 100200 mg/min, or in incremental doses, while keeping in constant verbal contact with the patient. If toxic symptoms occur, the injection should be stopped immediately.

Child Dosage

Contra Indications

Known hypersensitivity to anaesthetics of the amide type or other components of the solution.

The use of a vasoconstrictor is contra-indicated for anaesthesia of fingers, toes, tip of nose, ears and penis.

Special Precautions

In common with other local anaesthetics, Xylocaine with Adrenaline should be used cautiously in patients with epilepsy, impaired cardiac conduction, impaired respiratory function and in patients with impaired hepatic function, if the dose or site of administration is likely to result in high blood levels. Patients with severe renal dysfunction, the elderly and patients in poor general condition also require special attention. Attempts should also be made to optimise the patient's condition before major blocks. Patients treated with anti-arrhythmic drugs class III (eg amiodarone) should be under close surveillance and ECG monitoring considered, since cardiac effects may be additive.

Xylocaine with Adrenaline should not be given intravenously.

Facilities for resuscitation should be available when local anaesthetics are administered.

The effect of local anaesthetics may be reduced if an injection is made into an inflamed or infected area.

Patients with acute porphyria. Xylocaine solution for injection 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.

Certain local anaesthetic procedures may be associated with serious adverse reactions, regardless of the local anaesthetic drug used, e.g.:

- Injections in the head and neck regions may be made inadvertently into an artery, causing cerebral symptoms even at low doses.

- Paracervical block can sometimes cause foetal bradycardia/tachycardia, and careful monitoring of the foetal heart rate is necessary.

Solutions containing adrenaline should be used with caution in patients with hypertension, cardiac disease, cerebrovascular insufficiency hyperthyroidism, advanced diabetes and any other pathological condition that may be aggravated by the effects of adrenaline.

Xylocaine with adrenaline contains sodium metabisulphite, which may cause allergic reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in certain susceptible people. The overall prevalence of sulphite sensitivity in the general population is unknown and probably low. Sulphite sensitivity is seen more frequently in asthmatic than non-asthmatic people.

Preservative containing solutions, i.e. those supplied in multidose vials should not be used for intrathecal and epidural anaesthesia or in doses more than 15 ml for other types of blockades.

Interactions

Lidocaine should be used with caution in patients receiving other local anaesthetics or agents structurally related to amide-type local anaesthetics e.g., certain anti-arrhythmics, such as mexilitine, since the systemic toxic effects are additive. Specific interaction studies with lidocaine and anti-arrhythmic drugs class III (e.g., amiodarone) have not been performed, but caution is advised.

Solutions containing adrenaline should be used cautiously in patients taking tricyclic antidepressants, monoamine oxidase inhibitors or receiving potent general anaesthetic agents since severe, prolonged hypertension may be the result. In addition, the concurrent use of adrenaline-containing solutions and oxytocic drugs of the ergot type may cause severe, persistent hypertension and possibly cerebrovascular and cardiac accidents. Phenothiazines and butyrophenones may oppose the vasoconstrictor effects of adrenaline giving rise to hypotensive responses and tachycardia.

Solutions containing adrenaline should be used with caution in patients undergoing general anaesthesia with inhalation agents, such as halothane and enflurane, due to the risk of serious cardiac arrhythmias.

Non-cardioselective betablockers such as propranolol enhance the pressor effects of adrenaline, which may lead to severe hypertension and bradycardia.

Adverse Reactions

In common with other local anaesthetics, adverse reactions to Xylocaine with Adrenaline are rare and are usually the result of excessively high blood concentrations due to inadvertent intravascular injection, excessive dosage, rapid absorption or occasionally to hypersensitivity, idiosyncrasy or diminished tolerance on the part of the patient. In such circumstances systemic effects occur involving the central nervous system and/or the cardiovascular system.

The following table gives a list of the frequencies of undesirable effects:

4.8.1 Acute systemic toxicity

Systemic toxic reactions primarily involve the central nervous system (CNS) and the cardiovascular system (CVS). Such reactions are caused by high blood concentrations of a local anaesthetic, which may appear due to (accidental) intravascular injection, overdose or exceptionally rapid absorption from highly vascularised areas. CNS reactions are similar for all amide local anaesthetics, while cardiac reactions are more dependent on the drug, both quantitatively and qualitatively. Signs of toxicity in the central nervous system generally precede cardiovascular toxic effects, unless the patient is receiving a general anaesthetic or is heavily sedated with drugs such as benzodiazepine or barbiturate.

Central nervous system toxicity is a graded response with symptoms and signs of escalating severity. The first symptoms are usually, circumoral paraesthesia, numbness of the tongue, light-headedness, hyperacusis, tinnitus and visual disturbances. Dysarthria, muscular twitching or tremors are more serious and precede the onset of generalised convulsions. These signs must not be mistaken for a neurotic behaviour. Unconsciousness and grand mal convulsions may follow which may last from a few seconds to several minutes. Hypoxia and hypercarbia occur rapidly following convulsions due to the increased muscular activity, together with the interference with respiration and possible loss of functional airways. In severe cases apnoea may occur. Acidosis hyperkalaemia, hypocalcaemia and hypoxia increase and extend the toxic effects of local anaesthetics.

Recovery is due to redistribution of the local anaesthetic drug from the central nervous system and subsequent metabolism and excretion. Recovery may be rapid unless large amounts of the drug have been injected.

Cardiovascular system toxicity may be seen in severe cases and is generally preceded by signs of toxicity in the central nervous system. In patients under heavy sedation or receiving a general anaesthetic, prodromal CNS symptoms may be absent. Hypotension, bradycardia, arrhythmia and even cardiac arrest may occur as a result of high systemic concentrations of local anaesthetics, but in rare cases cardiac arrest has occurred without prodromal CNS effects.

In children, early signs of local anaesthetic toxicity may be difficult to detect in cases where the block is given during general anaesthesia.

4.8.2 Treatment of acute toxicity

If signs of acute systemic toxicity appear, injection of the local anaesthetic should be stopped immediately and CNS symptoms (convulsion, CNS depression) must promptly be treated with appropriate airway/respiratory support and the administration of anticonvulsant drugs.

If circulatory arrest should occur, immediate cardiopulmonary resuscitation should be instituted. Optimal oxygenation and ventilation and circulatory support as well as treatment of acidosis are of vital importance.

If cardiovascular depression occurs (hypotension, bradycardia), appropriate treatment with intravenous fluids, vasopressor, chronotropic and or inotropic agents should be considered. Children should be given doses commensurate with age and weight.

Manufacturer

Drug Availability

Updated