Subcutaneous or intradermal local anaesthetics for acute pain management

Local anaesthetics can be injected into tissue subcutaneously or intradermally; this technique is sometimes referred to as infiltration. Compared to topical application, infiltration is faster acting and can provide analgesia or anaesthesia to deeper tissues. It is commonly used for:

  • dental procedures
  • wound closure and debridement
  • management of postoperative wound pain—up to 6 hours of analgesia can be achieved by injecting a long-acting local anaesthetic into a surgical wound
  • invasive procedures (eg lumbar puncture).

The pain of local anaesthetic infiltration can be reduced by slow injection, a small needle (eg 27 gauge), warming the solution to body temperature, or buffering lidocaine1.

Do not exceed maximum local anaesthetic doses (see Maximum single doses of local anaesthetics). The maximum weight-based dose is often calculated and administered in small increments until the desired effect is achieved. The dose required may be substantially less than the maximum dose; see Dosing local anaesthetics for acute pain management.

1 Buffering reduces injection pain by alkalinisation but may result in precipitation. An example of how to buffer lidocaine is to add 1 mL of 8.4% sodium bicarbonate solution to 9 mL of lidocaine 1% solution.Return