Xylocaine Injection Special Precautions

When any local anaesthetic agent is used, resuscitative equipment and drugs, including oxygen, should be immediately available in order to manage possible adverse reactions involving the cardiovascular, respiratory or CNS. Because of the possibility of hypotension and bradycardia following major blocks, an IV cannula should be inserted before the local anaesthetic is injected. Delay in proper management of dose-related toxicity, underventilation from any cause and/or altered sensitivity may lead to the development of acidosis, cardiac arrest and death.
Injection should always be made slowly with frequent aspirations to avoid inadvertent IV injection which can produce cerebral symptoms even at low doses.
Although intra-articular continuous infusions of local anaesthetics following arthroscopic and other surgical procedures is an unapproved use, there have been post-marketing reports of chondrolysis in patients receiving such infusions. The majority of reported cases of chondrolysis have involved the shoulder joint; cases of gleno-humeral chondrolysis have been described in paediatric and adult patients following intra-articular continuous infusions of local anaesthetics with and without adrenaline for periods of 48 to 72 hours. There is insufficient information to determine whether shorter infusion periods are not associated with these findings. The time of onset of symptoms, such as joint pain, stiffness and loss of motion can be variable, but may begin as early as the 2nd month after surgery. Currently, there is no effective treatment for chondrolysis; patients who experienced chondrolysis have required additional diagnostic and therapeutic procedures and some required arthroplasty or shoulder replacement. Therefore, Xylocaine and Xylocaine with Adrenaline should not be used for post-operative intra-articular continuous infusion.
Careful and constant monitoring of cardiovascular and respiratory vital signs and the patient's state of consciousness should be accomplished after each local anaesthetic injection. It should be kept in mind that at such times restlessness, anxiety, tinnitus, dizziness, blurred vision, tremors, depression or drowsiness may be early warning signs of CNS toxicity.
Low Molecular Weight Heparins and Heparinoids (Spinal/Epidural Haematomas): When neuraxial anaesthesia (epidural/spinal anaesthesia) is employed, patients anticoagulated or scheduled to be anticoagulated with low molecular weight heparins or heparinoids are at risk of developing an epidural or spinal haematoma which can result in long-term or permanent paralysis. The risk of these events is increased by the use of indwelling epidural catheters, traumatic or repeated epidural/spinal puncture, and the concomitant use of drugs affecting haemostasis eg, NSAID, platelet inhibitors or other anticoagulants. Patients should be frequently monitored for signs and symptoms of neurological impairment.
The safety and effectiveness of Xylocaine Injection depends on the proper dosage, correct technique and adequate precautions. Standard textbooks should be consulted regarding specific techniques and precautions for various regional anaesthetic procedures.
The lowest dosage that results in effective anaesthesia should be used (see Dosage & Administration). Repeated injection of Xylocaine Injection may cause accumulation of lignocaine or its metabolites and may result in toxic effects.
Tolerance to elevated blood levels varies with the status of the patient. Elderly, young or debilitated patients, including those with advanced liver disease or severe renal dysfunction, should be given reduced doses commensurate with their age and physical condition.
Lignocaine should be given with great caution to patients with epilepsy, impaired cardiac conduction, bradycardia, severe shock or digitalis intoxication. It should also be administered with great caution to patients with impaired cardiovascular function as they may be less able to compensate for functional changes associated with the prolongation of AV conduction produced by these drugs. In patients with Stokes-Adams syndrome or Wolff-Parkinson-White syndrome, extreme care should be taken to avoid accidental arteriovenous injection.
Central nerve blocks may cause cardiovascular depression, especially in the presence of hypovolaemia. Epidural anaesthesia should be used with caution in patients with impaired cardiovascular function. Epidural anaesthesia may lead to hypotension and bradycardia. Hypotension should be treated promptly with sympathomimetics IV and repeated as necessary.
Local anaesthetics should be given with great caution (if at all) to patients with preexisting abnormal neurological pathology eg, myasthenia gravis. Use with extreme caution in epidural, caudal and spinal anaesthesia when there are serious diseases of the CNS or of the spinal cord eg, meningitis, spinal fluid block, cranial or spinal haemorrhage, tumours, poliomyelitis, syphilis, tuberculosis or metastatic lesions of the spinal cord.
Since lignocaine is metabolised in the liver and excreted via the kidneys, the possibility of drug accumulation should be considered in patients with hepatic and/or renal impairment (see Dosage & Administration).
Inadvertent IV or subarachnoid injection of small doses of local anaesthetics injected into the head and neck area including retrobulbar, dental and stellate ganglion blocks, may produce adverse reactions similar to systemic toxicity seen with unintentional IV injections of larger doses.
Clinicians who perform retrobulbar blocks should be aware that there have been reports of cardiovascular collapse and apnoea following the use of local anaesthetic injections for retrobulbar block. Prior to retrobulbar block, necessary equipment, drugs and personnel should be immediately available as with all other regional procedures. Retrobulbar injections may very occasionally reach the subarachnoid space causing temporary blindness, cardiovascular collapse, apnoea, convulsions, etc. These must be diagnosed and treated promptly.
Retro- and peribulbar injections of local anaesthetics carry a low risk of persistent ocular muscle dysfunction. The primary causes include trauma and/or local toxic effects on muscles and nerves. The severity of such tissue reactions is related to the degree of trauma, the concentration of the local anaesthetic and the duration of exposure of the tissue to the local anaesthetic. For this reason, as with all local anaesthetics, the lowest effective concentration and dose of local anaesthetic should be used. Vasoconstrictors may aggravate tissue reactions and should be used only when indicated.
Foetal bradycardia/tachycardia frequently follows paracervical block and may be associated with foetal acidosis and hypoxia. Occasional cases of perinatal morbidity and mortality have been reported. When the recommended dose is exceeded, the risk of foetal bradycardia increases. Careful monitoring of the foetal heart rate is necessary.
Lignocaine should be used with caution in patients with known drug sensitivities.
Patients being treated with anti-arrhythmic drugs class III (eg, amiodarone) should be under close surveillance and ECG monitoring since cardiac effects may be additive.
Xylocaine injection are 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.
Effects on the Ability to Drive or Operate Machinery: Depending on dosage, local anaesthetics may have a very mild effect on mental function and may temporarily impair locomotion and coordination.
Carcinogenicity, Mutagenicity & Impairment of Fertility: A 2-year oral toxicity study of 2,6-xylidine, a metabolite of lignocaine, has shown that in both male and female rats, 2,6-xylidine in daily doses of 900 mg/m² (150 mg/kg) resulted in carcinomas and adenomas of the nasal cavity. No nasal tumours were observed in the low dose (15 mg/kg or control animals). In addition, the compound also caused SC fibromas and/or fibrosarcomas in male and female rats (significant at 150 mg/kg).
The genotoxic potential of 2,6-xylidine has been studied with mixed results: Positive results were reported in assays for gene mutations (weakly positive in the Ames test with metabolic activation and in the mouse lymphoma assay) and chromosomal damage (chromosomal aberrations in Chinese hamster ovary cells at concentrations at which the drug precipitated from solution). No evidence of genotoxicity was found in in vivo assays for chromosomal damage (micronucleus assay) and DNA damage (unscheduled DNA synthesis). Covalent binding studies of DNA from liver and ethmoid turbinates in rats indicate that 2,6-xylidine may be genotoxic under certain conditions in vivo.
Use in pregnancy: The safe use of lignocaine during pregnancy has not been established. Although lignocaine has been used extensively for surgical procedures during pregnancy with no reports of ill effects to mother or foetus, there are no adequate or well-controlled studies in pregnant women of the effect of lignocaine on the developing foetus.
Lignocaine has been effectively used for obstetrical analgesia and adverse effects on the course of labour or delivery are rare. After epidural administration of lignocaine to women in labour, lignocaine crosses the placental barrier. However, concentrations in umbilical veins are lower than those found in the maternal circulation. It has been suggested that blood glucose levels should be checked in newborns after obstetric regional anaesthesia.
Adrenaline-free solutions should be used during labour for paracervical or pudendal blocks.
Note: Paracervical blocks may be associated with foetal bradycardia (see previous text).
Use in lactation: Lignocaine passes into breast milk. The amount of lignocaine appearing in breast milk from a nursing mother receiving parenteral lignocaine is unlikely to lead to a significant accumulation of the parent drug in the breastfed infant. The remote possibility of an idiosyncratic or allergic reaction in the breastfed infant from lignocaine remains to be determined.