Improvement in Endoscopic Mucosal Visibility Using a Pre-procedure Combination Drink of N-acetylcysteine and Simethicone: A Randomized Controlled Trial

Improvement in endoscopic mucosal visibility using a pre-procedure combination drink of N-acetylcysteine and simethicone: A Randomized controlled trial

Introduction:

Upper gastrointestinal endoscopy (UGIE) is one of the most frequently performed procedures for diagnosing and treating GI and liver-related disorders. Pre-procedure preparation and reporting of adequate preparation is the standard of care for colonoscopies but there is not uniformity in preparation for UGIE. Various studies have demonstrated that the incidence of missed diagnosis in endoscopies can be brought down by improving mucosal visibility. Endoscopic mucosal visibility can be impaired by various factors like poor technique, excessive mucus, residual food, inappropriate positioning, and more importantly the presence of mucosal froth and bubbles in the GI tract. Gastro-duodenal mucosa is lined by mucus comprising 95% water and 5% cross-linked glycoprotein(GP), which keeps mucus viscous and liquid. With fasting, GP content decreases making mucus more sticky. Several mucolytic and anti-foaming agents including pronase, simethicone, and N acetyl-cysteine(NAC) have been tried for this purpose. NAC is a derivative of the natural amino acid L-cysteine. It breaks the disulfide bridges in high molecular weight glycoproteins. Simethicone (polydimethylsiloxane or dimethicone + SiO2) is an anti-foaming surface-acting agent, which acts by reducing the surface tension of air bubbles, surface viscosity, and hydrophobicity. Simethicone is virtually non-toxic, without any drug interaction or systemic toxicity. Multiple studies have been conducted showing the safety and efficacy of simethicone, NAC, and their combination for improving endoscopic visibility. These pre-medications are already used for improving endoscopic visibility to detect early esophageal and gastric cancer.

Some studies from the western countries as well as the eastern world have highlighted the significant role of mucolytic and anti-foaming agents in improving mucosal visibility.

Monrroy et al, in 2017 conducted a double-blind randomized control trial in which 230 patients were divided into 5 groups (46 each) i.e no intervention group, water 100 ml (W) group, and interventional groups comprised of simethicone alone (S), simethicone plus NAC 500 mg (S + NAC500) and simethicone plus NAC1000 group. The solution was ingested 20 minutes before the UGIE. Gastric visibility was assessed in 4 segments using a pre-validated mucosal visibility scoring system based on a Likert scale and adequate visibility was defined as a score less than 7. In this study, they found that premedication by S+NAC500 and S+NAC100 improved visibility whereas visibility was worst in the W group.