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Impact of Timing of Premedication on Mucosal Visibility During Endoscopy: A Randomized Controlled Trial.

  • 2026-04-10
  • Journal of gastroenterology and hepatology 41(6)
    • Zaheer Nabi
    • Preethi Sudha Dasireddy
    • Mahiboob Sayyed
    • Praveen Reddy
    • Rajesh Goud
    • Hardik Rughwani
    • Aniruddha Pratap Singh
    • Pradev Inavolu
    • Palle Manohar Reddy
    • Jahangeer Basha
    • Rajesh Gupta
    • Manu Tandan
    • D Nageshwar Reddy

Study Design

Type
Randomized Controlled Trial (RCT)
Sample size
n = 1,200
Population
1200 adults undergoing elective upper GI endoscopy
Methods
double-blinded randomized controlled trial, premedication (simethicone + NAC) to endoscopy interval of 10-20, 21-30, or > 30 min vs placebo
Blinding
Double-blind
Duration
not applicable (single procedure, no intervention duration)
  • Large Human Trial

Background

Adequate gastric mucosal visibility (GMV) is essential for high quality upper gastrointestinal (GI) endoscopy. Simethicone and N-acetylcysteine (NAC) are commonly used to improve mucosal visibility, but the optimal timing of administration remains uncertain.

Objective

This double-blinded randomized controlled trial (RCT) evaluated the optimal interval between premedication (simethicone + NAC) and endoscopy for achieving adequate GMV.

Design

In this RCT, adults undergoing elective upper GI endoscopy were randomized to four groups: placebo (Group 1), premedication to endoscopy interval of 10-20 (Group 2), 21-30 (Group 3), or > 30 min (Group 4). GMV was scored in four gastric regions (antrum, distal body, proximal body, fundus) on a 4-point scale (range 4-16). The primary outcome was adequate GMV (total score < 7). Secondary outcomes included median total GMV score, region-wise mucosal visibility scores, lesion detection rate, and predictors of adequate GMV.

Results

A total of 1200 adults were randomized to four groups. Adequate GMV was significantly more frequent in Groups 3 (64.7%) and 4 (66.7%) than in placebo (2.7%) or Group 2 (25.0%). Subgroup analysis within Group 4 demonstrated a declining trend after 50 min. ROC analysis suggested an optimal cut-off of 25 min in predicting adequate GMV with area under the curve of 0.80. In region-wise analysis, mean visibility scores were lowest in antrum and distal body. There was no significant difference in the detection of gastric lesions across study groups (p = 0.913). No serious adverse events related to premedication were observed.

Conclusion

Premedication with simethicone and NAC significantly improves GMV. The improvement becomes optimal at 20-30 min after ingestion and is consistently maintained up to 50 min.

Trial registration

ClinicalTrials.gov identifier: NCT06581783.

Research Insights

Adverse Events Reported

  • N-Acetyl Cysteine→Overall tolerability

    No serious adverse events related to premedication were observed.

    Finding
    Reported
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