Injection Site Pain, Onset and Duration of Action of Botulinum Toxin Reconstituted in Normal Saline With and Without Sodium Bicarbonate: A Prospective, Single Center, Randomized, Double-Blind Interventional Study.

This study was designed to investigate the effects of botulinum toxin type A injections diluted with the mixture of sodium bicarbonate and normal saline on pain reduction, onset of action, and duration of action. This is a prospective, randomized, double-blind clinical study, which included 30 female patients (age >25). The patients were randomized to receive botulinum toxin injections diluted with normal saline and sodium bicarbonate on one side of the face and saline control injections on the other side. Pain severity was assessed using visual analogue scale. The onset and duration of action were recorded according to the patients' subjective opinions after 1 week and 3 months, respectively. Lower pain intensity ratings were observed when botulinum toxin was diluted with 0.05 and 0.1 mL of sodium bicarbonate as compared to saline. Regarding the onset of action, the botulinum toxin injections diluted with saline and 0.1-mL sodium bicarbonate side showed faster response in many patients than other dilutions ( < .001). Both the 0.05-mL and 0.1-mL sodium bicarbonate concentrations showed longer duration effects on patients than other concentrations. The use of sodium bicarbonate and saline in a mixture for the dilution of botulinum toxin can decrease patients' discomfort and provide a faster action with longer duration effects.