The safety and efficacy of 2% vitamin C solution spray for relief of mucosal irritation caused by Lugol chromoendoscopy: a multicenter, randomized, double-blind, parallel trial

The primum non nocere principle

“…Washing the esophageal mucosa of patients undergoing Lugol chromoendoscopy (10 mL 2% Lugol iodine solution) with a different solution, and evaluating patients' descriptions of their clinical symptoms after 5 and 35 minutes of ending the examinations, they compared the improving symptoms in 3 distinct groups of 80 patients each, using in the normal saline (NS) group an NS solution (20 mL), in the STS group a 5% STS, and, finally, in the VCS group, a 2% VCS. 23 With the reduction of acute and late adverse symptom severity scores as primary endpoints and the discoloration effect of esophageal brown iodine-stained mucosa as a secondary endpoint, they found no difference between the STS and VCS groups regarding the reduction of both acute and late adverse symptom scores except when they were determined against NS, where both were superior. 23 Interestingly, the authors also found that VCS better alleviated acute acid regurgitation and late retrosternal discomfort or pain when compared with STS.…”

“…23 With the reduction of acute and late adverse symptom severity scores as primary endpoints and the discoloration effect of esophageal brown iodine-stained mucosa as a secondary endpoint, they found no difference between the STS and VCS groups regarding the reduction of both acute and late adverse symptom scores except when they were determined against NS, where both were superior. 23 Interestingly, the authors also found that VCS better alleviated acute acid regurgitation and late retrosternal discomfort or pain when compared with STS. VCS and STS quickly discolored the iodine-stained mucosa in a similar way, performing better than NS.…”

“…In this issue of Gastrointestinal Endoscopy, the study by Jin et al, 23 "The safety and efficacy of 2% vitamin C solution (VCS) spray for relief of mucosal irritation caused by Lugol chromoendoscopy: a multicenter, randomized, double-blind, parallel trial," may shed light on relieving the discomfort of symptoms from the topical application of Lugol's solution. Following an old statement that says "to have something new, somebody needs to do something never tried before," the authors tested spraying VCS on mucosal surface after iodine solution and proved that it also neutralizes free iodine, relieving the subsequent adverse symptoms.…”

“…Commended on having first tested the effect of different concentrations of vitamin C both in vitro and ex vivo (experiments on pig esophageal specimens), the authors observed that a 2% VCS had an optimal discoloration effect on the esophageal brown iodine-stained mucosa without histologic damage. 23 Only then did they translate the results of these bench studies into a noninferiority randomized translational trial. Washing the esophageal mucosa of patients undergoing Lugol chromoendoscopy (10 mL 2% Lugol iodine solution) with a different solution, and evaluating patients' descriptions of their clinical symptoms after 5 and 35 minutes of ending the examinations, they compared the improving symptoms in 3 distinct groups of 80 patients each, using in the normal saline (NS) group an NS solution (20 mL), in the STS group a 5% STS, and, finally, in the VCS group, a 2% VCS.…”

“…VCS and STS quickly discolored the iodine-stained mucosa in a similar way, performing better than NS. 23 Despite the encouraging results obtained with VCS, one must remember that this trial was designed as a noninferiority comparison, ie, the study aimed to demonstrate that an experimental treatment is not substantially worse than a control treatment (placebo or active control). Noninferiority trials may be performed in situations where conducting a placebo control trial is unethical.…”