Sorry, I'm not sure what the "alternate drug" is. I am not too familiar with HC's liver flush.
Another option you have is to just take 1 dose of ES, like 1 tablespoon, 1-2 hours before the oil/juice. But then, this won't give you diarrhea, and so you would have to do another method of bowel cleansing the day after the flush, like a salt water flush or colonic.