Injection Site Pain Botulinum Toxin Reconstituted in NS With and Without Sodium Bicarbonate

This study was designed to investigate the effects of botulinum toxin type A injections diluted with the mixture of sodium bicarbonate (SB) and normal saline (NS) 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 (BT) injections diluted with NS and SB 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. The study was approved with an IRB (Institutional Review Board) number of RC19/371.