Painless Injections – Taking The Sting Out


By Chris Faubel, MD —

In pain medicine we treat a myriad of conditions with various injections (epidural steroid injections, peripheral joint injections, trigger point injections, prolotherapy, sympathetic blocks, botulinum toxin, etc.).  One thing that all of those procedures have in common, is a needle.

Whether it’s the needle itself, or the acidic lidocaine, our injections have some degree of pain.

Besides using the smallest diameter needle possible for the respective procedure, there are other methods we can employ to eliminate or minimize the injection pain.

Vapocoolant sprays

  • Gebauer’s Spray and Stretch

    • Fluoropropane and fluoroethane mixture
    • Equivalent cooling effect as Fluori-Methane (see chart to right)
  • Ethyl Chloride spray
    • Most common one used before injection
    • Very flammable
    • Can vs Bottle
      • The bottle needs to be turned over completely and the lever squeezed fully to get a good stream; otherwise it trickles out and is wasted.
      • The bottle is more expensive
      • The can comes in stream and mist spray patterns for more variety (personal preference)
  • Pain Ease
  • Pain Ease, Ethyl Chloride, and Spray and Stretch all have equivalent cooling profiles

EMLA cream

  • Lidocaine 2.5% and Prilocaine 2.5%
  • Directions
    • Apply a thick layer of cream and cover with an occlusive dressing (duoderm, tegaderm)
  • Down side
    • Have to wait 30-60 minutes after applying the cream

Ice cubes

  • Problem: cumbersome and messy

Sodium bicarbonate buffering of lidocaine

  • The burning sensation of lidocaine being injected into the patient’s skin may quite possibly be the most painful aspect of the injection process.
  • Lidocaine is more acidic than human tissue, and this is believed to be the reason for the burning sensation.
  • Bicarbonate neutralizes the acidic lidocaine –> Less pain
  • Directions
    • Add 1ml of 8.4% sodium bicarbonate to a 10ml bottle of lidocaine (with or without epinephrine)
    • Note: the buffered lidocaine decreases the effectiveness of the epinephrine. But since we rarely use epinephrine with our injections in pain medicine, this is less relevant to us.
  • The buffered lidocaine has also been shown to have even more antibacterial activity [3]

Warm the lidocaine and inject slowly

  • Body temperature lidocaine produces less pain than room temperature [4]
  • One study found that the rate of administration of lidocaine had a greater impact on the perceived pain of lidocaine infiltration than did buffering. [5]


1 – Weiss RA, Lavin PT.  “Reduction of Pain and Anxiety Prior to Botulinum Toxin Injections With a New Topical Anesthetic Method“.  Ophthal Plast Reconstr Surg. Vol 25, No 3, 2009: 173-177

2 – Non- ozone depleting vapocoolants.

3 – Thompson et al.  “Antibacterial activity of lidocaine in combination with a bicarbonate buffer”.  J Dermatol Surg Oncol. 1993 Mar;19(3):216-20.

4 – Bainbridge LC. “Comparison of room temperature and body temperature local anaesthetic solutions.”  Br J Plast Surg. 1991 Feb-Mar;44(2):147-8.

5 – Scarfone RJ, Jasani M, Gracely EJ. “Pain of local anesthetics: rate of administration and buffering“.  Ann Emerg Med. 1998 Jan;31(1):36-40.

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  1. We use EMLA cream in our botox clinic very frequently. We use a pea size amount of the cream and use a duoderm dressing to help it stay in place. Most patients report excellent analgesic result after 30 minutes of application.

  2. We use Ethyl Chloride spray as well. For most peripheral joint injections the EMLA + Ethyl Chloride combination works well. But usually there is not enough time in clinic to wait for the EMLA to kick in so we just use the Ethyl Chloride.


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