While certain liquors are technically clear liquid (which is allowed during colonoscopy prep), "alcohol can cause ... reduce ...
[27] The new version preserves the '2-6-8 rule' for preprocedure fasting – that is, a minimum fasting period of 2 h is required for clear ... their preparation the evening prior to colonoscopy ...
Beyond that, Jacobson noted, higher risk patients can take a split-dose 4-L prep regimen with bisacodyl, a low-fiber diet 2-3 days before colonoscopy, and a clear liquid diet the day before ...