prilocaine hydrochloride: clinical use

Prescribing considerations

• Restricted to adult hospital practice under specialist anaesthetic supervision.
• Ensure venous access and immediate availability of airway, oxygenation and resuscitation equipment.
• Use particular caution with older or frail patients, late pregnancy, conduction disease, cardiac impairment, acute porphyria, or advanced hepatic or renal dysfunction.
• The glucose-containing hyperbaric formulation is intended only for spinal anaesthesia.

Contraindications and cautions

• Hypersensitivity to prilocaine, another amide local anaesthetic or an excipient
• Serious cardiac-conduction disorders
• Severe anaemia, decompensated heart failure, cardiogenic shock or hypovolaemic shock
• Congenital or acquired methaemoglobinaemia
• Concomitant anticoagulant treatment or another contraindication to subarachnoid anaesthesia
• Intravascular administration or injection into an infected area
• Use in children younger than 6 months; use in all children and adolescents is not recommended because efficacy and safety are unestablished

Monitoring

• Continuously assess blood pressure, heart rate, respiration, consciousness and block progression.
• Maintain verbal contact where possible and watch for early neurological or cardiovascular toxicity.
• Investigate unexplained cyanosis or low oxygen-saturation readings for methaemoglobinaemia.
• Monitor closely for high or total spinal block, particularly in older patients and late pregnancy.

Clinical pharmacology

Prilocaine blocks voltage-dependent sodium conductance, reversibly reducing sensory, motor and autonomic nerve excitability. It is metabolised mainly in the liver and kidneys; its o-toluidine metabolite can oxidise haemoglobin to methaemoglobin.

Formulation and product differences

• The selected product is a clear, colourless, glucose-containing hyperbaric solution for intrathecal use.
• It is not recommended for epidural anaesthesia and must not be injected intravenously.
• Ampoules are single-use and any remainder must be discarded.
• The formulation is essentially sodium-free.

Injection

Route: Parenteral

Strengths: 20 mg/mL, 1%