- Intake of medication, whether prescribed or over the counter (except multivitamins), within 7 days of the study. Exceptions are birth control pill, estrogen replacement therapy, thyroxine replacement therapy, low dose analgesia or anti-inflammatory medications (Acetaminophen and Ibuprofen) and any medication administered for co-morbidities as long as they do not alter gastrointestinal motility including gastric emptying and gastric accommodation.