What are the preparations of lignocaine (lidocaine)?

Preparations of Lignocaine (Lidocaine)

Available Formulations and Concentrations

Lignocaine is available in multiple formulations ranging from 0.5% to 10% concentrations, delivered as solutions for injection, topical gels, sprays, and nebulized preparations, with specific formulations selected based on the anatomical site and clinical indication. 1, 2

Injectable Solutions

• 0.5% solution (5 mg/mL): Available in 50 mL single-dose vials containing 250 mg total 2
• 1% solution (10 mg/mL): Available in multiple formats including 2 mL ampules (20 mg), 20 mL vials (200 mg), and 50 mL vials (500 mg) 2
• 2% solution (20 mg/mL): Available in 2 mL ampules (40 mg), 10 mL ampules (200 mg), 20 mL vials (400 mg), and 50 mL vials (1000 mg) 2
• 10% solution: Available for intramuscular injection, producing similar blood levels to larger volumes of less concentrated preparations 3

Topical Preparations for Airway Procedures

• 2% gel (w/v): Preferred for nasal anaesthesia as it is better accepted by patients and yields lower blood levels compared to spray formulations 1
• 4% aerosol (w/v): Used for anterior nares anaesthesia 1
• 10% aerosol spray: Used for oropharyngeal anaesthesia 1
• 4% nebulised solution: 4 mL administered via mouthpiece for oropharynx and vocal cord anaesthesia 1
• 2-4% solution: Used for "spray as you go" technique during bronchoscopy 1
• 1-2% boluses: Sprayed via bronchoscope for carina and bronchial anaesthesia 1

Formulations with Epinephrine (Adrenaline)

• 1% lignocaine with epinephrine 1:200,000: The agent of choice for skin surgery, allowing maximum dose of 40 mL 4
• Epinephrine-containing solutions increase maximum allowable doses by delaying local anaesthetic clearance and reducing peak blood concentrations 4
• Should be avoided at fingers, toes, and penis due to risk of vasoconstriction-induced ischemia 4

Packaging and Storage Considerations

Container Types

• Single-dose ampules: Preservative-free, available in glass 2
• Single-dose vials: Preservative-free, available in glass teartop format 2
• Multiple-dose vials: Contain 0.1% methylparaben as preservative, available in plastic fliptop format 2

Storage and Sterilization

• Store at 20-25°C (68-77°F) under controlled room temperature conditions 2
• Solutions in ampules and glass vials may be autoclaved once only at 15 pounds pressure, 121°C (250°F) for 15 minutes 2
• Do not autoclave products in plastic vials 2

pH and Buffering Modifications

• Standard lignocaine solutions have pH 6.5 (range 5.0-7.0) 2
• Buffering with 8.4% sodium bicarbonate in 1:10 dilution significantly reduces injection pain and accelerates onset of anaesthesia (mean onset 34.4 seconds vs 109.8 seconds unbuffered) 5, 6
• Epinephrine-containing solutions require acidic sodium metabisulphite to prevent oxidation, increasing injection pain, which can be mitigated by buffering 4

Temperature Considerations

• Warming lignocaine to 37°C (body temperature) significantly reduces injection pain compared to room temperature administration (median pain score 10.0 vs 19.5) 7

Common Pitfalls to Avoid

• Avoid using epinephrine-containing solutions in end-arterial territories (digits, penis) where vasoconstriction can cause tissue necrosis 4
• Do not autoclave plastic vial preparations as this damages the container 2
• Be aware that epinephrine-containing solutions have drug interactions with tricyclic antidepressants and nonselective beta-blockers 4
• Multiple-dose vials contain methylparaben preservative which may cause allergic reactions in susceptible patients 2