A systematic review of taste-masking strategies for polyethylene glycol-based bowel preparation

Background: The acceptability of bowel cleansing agents is critical for ensuring adequate bowel preparation prior to colonoscopy. However, the unpleasant taste of Polyethylene glycol (PEG)-based preparations often hinders patient adherence, leading to inadequate bowel cleansing, increased resource burdens, and the potential for missed diagnoses. This systematic review aims to evaluate current taste-masking strategies used to enhance the acceptability of PEG-based bowel preparations.Methods: A systematic search of Scopus, PubMed, the Cochrane Database of Systematic Reviews, MEDLINE and EMBASE (Ovid interface), identified prospective randomized controlled trials (RCTs) evaluating current taste-masking strategies applied to PEG-based bowel preparations. The primary data extraction was acceptability, measured by level of palatability and willingness to repeat the medication. Subsequent data extraction encompassed four gastrointestinal adverse events and bowel preparation quality. Meta-analysis was performed using a random-effects Mantel-Haenszel model, with heterogeneity quantified via I-squared (I2) statistic.Findings: 41 RCTs were analysed, comprising 29 on component adjustments (e.g., ascorbic acid, sulphate), five on adjuncts for palatability (e.g., menthol candy drops, citrus reticulata peel), four on alternatives to water as diluent, two on flavourings, and one on encapsulation. Low-volume PEG formulations, with extra ascorbic acid and reduced sodium ascorbate concentrations improved taste profile (p < 0·05). Simethicone-containing and sulphate-free (SF) formulations reduced bloating (p = 0·005) and abdominal pain (p = 0·02), respectively, but did not enhance acceptability. Component or flavouring modifications alone showed no significant impact on overall acceptability (all p> 0·05). Adjuncts improved palatability (odds ratio (OR): 2·15, 95% confidence interval (CI): 1·36 to 3·40, p = 0·001; mean difference (MD): 0·83, 95% CI: 0·32 to 1·34, p = 0·001) and willingness to repeat the regimen (OR: 2·20, 95% CI: 1·40 to 3·48, p = 0·0007). Water alternatives and encapsulation significantly increased acceptability without compromising tolerability or bowel cleansing quality (p < 0·05). No publication bias was observed via Risk of Bias 2 (RoB2) tool, although heterogeneity differed among outcomes.Interpretation: The findings enhance current clinical and pharmaceutical practices by systematically identifying strategies to enhance patient experience and guiding the development of more acceptable patient-centric formulation.