[Skip to Content]
[Skip to Content Landing]
October 3, 2001

Pain Associated With Injection Using Frozen vs Room-Temperature Needles

Author Affiliations

Copyright 2001 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.2001

JAMA. 2001;286(13):1578. doi:10.1001/jama.286.13.1573

To the Editor: Although typical cooling agents such as ice packs and ethyl chloride sprays are often used to achieve local anesthesia, the effect of lowering the temperature of piercing agents has not been studied.

I studied 77 patients who were receiving bilateral injections of botulinum toxin (12.5 units per injection) symmetrically into the right and left facial corrugator muscles using a 30-gauge needle. Each patient received 1 of the injections with a room-temperature needle and the other with with a needle that had been frozen overnight at −7°C. An assistant placed the needles on the syringes, and both patients and physicians were blinded to the condition. The needles were randomized as to the order in which they were used. Patients immediately reported the severity of their pain using a pain scale of 0 to 10. Results were analyzed using the paired t test.