Effect of the Antihistamine Injection to Prevent Paradoxical Reaction During Sedative Endoscopy

Effect of an Adjunctive Sedative for the Patients With Histories of Paradoxical Reaction to Midazolam During Sedative Endoscopy

This single-blind prospective study is aimed to investigate the effect of antihistamine as an adjunctive sedative for the patients with histories of severe paradoxical reaction to midazolam during sedative endoscopy. Participating patients are to receive antihistamine intravenously in addition to midazolam. The primary outcome is the reduction of paradoxical reaction in the antihistamine combination group. The secondary outcome is to compare sedation quality, performance quality, reduction of total midazolam dose will be analyzed between antihistamine combination and midazolam only group.

The present study will be conducted at Seoul National University Hospital Gangnam center between May 2019 and April 2020. Participants who have histories of paradoxical reaction to sedative endoscopy in medical record gave consent on the day of the endoscopy and were assigned to receive the combination of chlorpheniramine (4-6mg) with midazolam(1-10mg) Meanwhile, the patients do not want the use of chlorpheniramine and were assigned to midazolam alone as routine clinical practice. Research medication (chlorpheniramine) was administered 2 to 3 minutes before the administration of midazolam outside of endoscopy room. The blinded endoscopist and assistant nurse are going to perform induction for moderate sedation using incremental doses of the intravenous midazolam (1-2 mg) given every 2 minutes. The endoscopists and assistant nurses will assess the occurrence of severe paradoxical reaction (Grade 3) and other major quality outcomes (procedure/intubation time, sedation quality, completeness of procedure [10 Key image documentation], the satisfaction of procedure, side effects). The endoscopists and nurses will individually rate outcome measure using a 5-point Likert scale.

Inclusion Criteria:

• Previous histories of the paradoxical reaction during a sedative endoscopic examination

Exclusion Criteria:

• inability to execute informed consent
• allergic to antihistamine agent
• pregnancy
• severe cardiopulmonary disease
• prior administration of antihistamine on the same day