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Updated: Oct 1, 2026

Ultrasound-guided Botulinum Toxin-A Injections: A Method of Treating Sialorrhea
Published on: November 9, 2016
Pain associated with injection of botulinum A exotoxin reconstituted using isotonic sodium chloride with and without
Murad Alam1, Jeffrey S Dover, Kenneth A Arndt
1SkinCare Physicians, Chestnut Hill, Massachusetts, USA. murad@alam.com
Context:
Botulinum A exotoxin is used for various indications, including the treatment of dynamic forehead lines.
Objective:
To determine whether injection with botulinum A exotoxin reconstituted with preservative-containing normal saline (isotonic sodium chloride) is less painful than injection with exotoxin that has been reconstituted with preservative-free saline.
Design:
Two arms: (1) retrospective study; (2) double-blind, randomized controlled trial.
Setting:
A multiple-physician dermatology practice.
Patients:
(1) Retrospective study-20 consecutive adult patients presenting for treatment of upper-face dynamic lines; (2) prospective study-15 consecutive adult patients presenting for treatment of upper-face dynamic lines.
Intervention:
In prospective study only, one side (left or right) of the face was treated with exotoxin reconstituted with preservative-containing saline, and the other side, with exotoxin reconstituted with preservative-free saline.
Main Outcome Measures:
(1) Retrospective study-discomfort at current treatment (with preservative-containing saline) compared with discomfort with most recent prior treatment (with preservative-free saline); (2) prospective study-discomfort on the side treated with preservative-containing saline compared with discomfort on the side treated with preservative-free saline.
Results:
(1) Retrospective study-18 (90%) of 20 patients reported that treatment with exotoxin reconstituted with preserved saline was less painful than prior treatment with exotoxin reconstituted with preservative-free saline; (2) prospective study-15 (100%) of 15 patients reported less pain in the side of their face treated with exotoxin reconstituted with preservative-containing saline (P<.001). Pain on the preservative-containing side was 54% less. No difference in treatment efficacy between the sides was observed by investigators or patients.
Conclusion:
Use of preservative-containing saline to reconstitute botulinum A exotoxin can significantly decrease patient discomfort on injection.
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