Drug Class Description

Generic Name

Drug Description

Presentation

Indications

Intrathecal (subarachnoid) spinal anaesthesia for surgery (urological and lower limb surgery lasting 2–3 hours, abdominal surgery lasting 45–60 minutes). Bupivacaine is a long-acting anaesthetic agent of the amide type. Marcain Heavy has a rapid onset of action and long duration. The duration of analgesia in the T10–T12 segments is 2–3 hours.

Marcain Heavy produces a moderate muscular relaxation of the lower extremities lasting 2–2.5 hours. The motor blockade of the abdominal muscles makes the solution suitable for performance of abdominal surgery lasting 45–60 minutes. The duration of the motor blockade does not exceed the duration of analgesia. The cardiovascular effects of Marcain Heavy are similar or less than those seen with other spinal agents.

Bupivacaine 5 mg/ml with glucose 80 mg/ml is exceptionally well tolerated by all tissues with which it comes in contact.

Adult Dosage

Route of administration: For intrathecal injection.

The doses recommended below should be regarded as a guide for use in the average adult.

Intrathecal anaesthesia for surgery:

2-4ml (10-20mg bupivacaine hydrochloride).

The dose should be reduced in the elderly and in patients in the late stages of pregnancy.

The spread of anaesthesia obtained with Marcain Heavy depends on several factors including the volume of solution and the position of the patient during and following the injection.

When injected at the L₃–L₄ intervertebral space, with the patient in the sitting position, 3 ml of Marcain Heavy spreads to the T₇–T₁₀ spinal segments. With the patient receiving the injection in the horizontal position and then turned supine, the blockade spreads to T₄–T₇ spinal segments. It should be understood that the level of spinal anaesthesia achieved with any local anaesthetic can be unpredictable in a given patient.

The recommended site of injection is below L3.

The effects of injections of Marcain Heavy exceeding 4 ml have not yet been studied and such volumes can therefore not be recommended.

Child Dosage

Contra Indications

Hypersensitivity to local anaesthetics of the amide type or to any of the excipients.

Intrathecal anaesthesia, regardless of the local anaesthetic used, has its own contraindications, which include:

• Active disease of the central nervous system such as meningitis, poliomyelitis, intracranial haemorrhage, sub-acute combined degeneration of the cord due to pernicious anaemia and cerebral and spinal tumours.

• Spinal stenosis and active disease (e.g. spondylitis, tuberculosis, tumour) or recent trauma (e.g. fracture) in the vertebral column.

• Septicaemia.

• Pyogenic infection of the skin at or adjacent to the site of lumbar puncture.

• Cardiogenic or hypovolaemic shock.

• Coagulation disorders or ongoing anticoagulation treatment.

Special Precautions

Intrathecal anaesthesia should only be undertaken by clinicians with the necessary knowledge and experience.

Regional anaesthetic procedures should always be performed in a properly equipped and staffed area. Resuscitative equipment and drugs should be immediately available and the anaesthetist should remain in constant attendance.

Intravenous access, e.g. an i.v. infusion, should be in place before starting the intrathecal anaesthesia. The clinician responsible should take the necessary precautions to avoid intravascular injection and be appropriately trained and familiar with the diagnosis and treatment of side effects, systemic toxicity and other complications. If signs of acute systemic toxicity or total spinal block appear, injection of the local anaesthetic should be stopped immediately.

Like all local anaesthetic drugs, bupivacaine may cause acute toxicity effects on the central nervous and cardiovascular systems, if utilised for local anaesthetic procedures resulting in high blood concentrations of the drug. This is especially the case after unintentional intravascular administration or injection into highly vascular areas.

Ventricular arrhythmia, ventricular fibrillation, sudden cardiovascular collapse and death have been reported in connection with high systemic concentrations of bupivacaine. Should cardiac arrest occur, a successful outcome may require prolonged resuscitative efforts. High systemic concentrations are not expected with doses normally used for intrathecal anaesthesia.

There is an increased risk of high or total spinal blockade, resulting in cardiovascular and respiratory depression, in the elderly and in patients in the late stages of pregnancy. The dose should therefore be reduced in these patients.

Intrathecal anaesthesia with any local anaesthetic can cause hypotension and bradycardia which should be anticipated and appropriate precautions taken. These may include preloading the circulation with crystalloid or colloid solution. If hypotension develops it should be treated with a vasopressor such as ephedrine 10–15 mg intravenously. Severe hypotension may result from hypovolaemia due to haemorrhage or dehydration, or aorto-caval occlusion in patients with massive ascites, large abdominal tumours or late pregnancy. Marked hypotension should be avoided in patients with cardiac decompensation.

Patients with hypovolaemia due to any cause can develop sudden and severe hypotension during intrathecal anaesthesia.

Intrathecal anaesthesia can cause intercostal paralysis and patients with pleural effusions may suffer respiratory embarrassment. Septicaemia can increase the risk of intraspinal abscess formation in the postoperative period.

Neurological injury is a rare consequence of intrathecal anaesthesia and may result in paraesthesia, anaesthesia, motor weakness and paralysis. Occasionally these are permanent.

Before treatment is instituted, consideration should be taken if the benefits outweigh the possible risks for the patient.

Patients in poor general condition due to ageing or other compromising factors such as partial or complete heart conduction block, advanced liver or renal dysfunction require special attention, although regional anaesthesia may be the optimal choice for surgery in these patients.

Patients treated with anti-arrhythmic drugs class III (e.g. amiodarone) should be kept under close surveillance and ECG monitoring considered, since cardiac effects may be additive.

Interactions

Bupivacaine 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 lidocaine and mexiletine, since the systemic toxic effects are additive.

Specific interaction studies with bupivacaine and anti-arrhythmic drugs class III (e.g. amiodarone) have not been performed, but caution is advised.

Adverse Reactions

General

The adverse reaction profile for Marcain Heavy is similar to those for other long acting local anaesthetics used for intrathecal anaesthesia.

Table of Adverse Drug Reactions

Adverse reactions caused by the drug per se are difficult to distinguish from the physiological effects of the nerve block (e.g. decrease in blood pressure, bradycardia, temporary urinary retention), events caused directly (e.g. spinal haematoma) or indirectly (e.g. meningitis, epidural abcess) by needle puncture or events associated to cerebrospinal leakage (e.g. postdural puncture headache).

Acute systemic toxicity

Marcain Heavy, used as recommended, is not likely to cause blood levels high enough to cause systemic toxicity. However, if other local anaesthetics are concomitantly administered, toxic effects are additive and may cause systemic toxic reactions.

Systemic toxicity is rarely associated with spinal anaesthesia but might occur after accidental intravascular injection. Systemic adverse reactions are characterised by numbness of the tongue, light-headedness, dizziness and tremors, followed by convulsions and cardiovascular disorders.

Treatment of acute systemic toxicity

No treatment is required for milder symptoms of systemic toxicity but if convulsions occur then it is important to ensure adequate oxygenation and to arrest the convulsions if they last more than 15–30 seconds. Oxygen should be given by face mask and the respiration assisted or controlled if necessary. Convulsions can be arrested by injection of thiopental 100–150 mg intravenously or with diazepam 5–10 mg intravenously. Alternatively, succinylcholine 50–100 mg intravenously may be given but only if the clinician has the ability to perform endotracheal intubation and to manage a totally paralysed patient.

High or total spinal blockade causing respiratory paralysis should be treated by ensuring and maintaining a patent airway and giving oxygen by assisted or controlled ventilation.

Hypotension should be treated by the use of vasopressors, e.g. ephedrine 10–15 mg intravenously and repeated until the desired level of arterial pressure is reached. Intravenous fluids, both electrolytes and colloids, given rapidly can also reverse hypotension.

Manufacturer

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