Intragastric injection of botulinum toxin A (BT-A) has been shown to be
effective for weight loss up to six months after administration, according to previous studies. Our
objective was to determine, in patients on bariatric surgery waiting lists, the effect of BT-A on weight
loss in the pre- and postoperative period and to analyse if there are different responses based on
Body Mass Index (BMI). Methods: We performed a follow-up analysis of the IntraTox study, which
included 46 patients on bariatric surgery waiting lists in a single-centre, randomised, double-blind,
placebo-controlled clinical trial. The treatment group received intragastric BT-A, whereas the control
group received physiological saline solution. The one-time procedure was performed at the time
of diagnostic endoscopy 7–8 months before surgery. Weight loss was evaluated at admission and
after 4 and 12 weeks from the bariatric surgery. Our analysis was stratified by BMI at randomisation.
Results: weight loss percentage on the day of surgery, with respect to the initial visit, was −4.5 ± 3.9%
for the control group vs. −7.6 ± 4.2%, for the treatment group (p = 0.013). Weight loss percentage
tended to remain greater in the treatment group one month after the intervention (−12.7 ± 4.7% vs.
−15.2 ± 4.6%, p = 0.07) and become similar three months after (−21.6 ± 4.7% vs. −21.6 ± 4.6%). After
stratifying by BMI, only patients with BMI over 50 kg/m2 allocated to the treatment group obtained
a greater weight loss at the end of the trial, the day of surgery, and one month after, compared with
the placebo group (−4.9 ± 4.9%, −10.8 ± 5.3% and −17.1 ± 3.8% vs. −0.1 ± 2.6%, −4.3 ± 3.2%
and −12.8 ± 4.1%, respectively (p < 0.05). Conclusions: intragastric injection of BT-A is effective to
achieve significant weight loss, especially in extreme obesity. Its use before bariatric surgery enhances
perioperative weight loss.
