One of the most serious side effects of drugs administered for sedation is untoward respiratory events. The relative prevalence of such events is thought to be high, occurring in up to 41% of patients in some cohorts. Many specific drugs and combinations have been recommended for moderate sedation, particularly when provided by a non-anesthesiologist. The use of an opioid and a benzodiazepine is the most frequent combination, partly because the availability of antagonists for both drugs may make a "rescue" easier. However, this combination results in frequent respiratory arrhythmias (combinations of obstructions, pauses and changes in respiratory patterns).There has not been a comprehensive study of the mechanisms underlying the disruptions of respiratory rhythm caused by agents commonly used for moderate sedation. This specific research, and the line of research it opens, has the potential to make the administration of anxiolytics and analgesics safer for patients at high risk for respiratory events.