Morphine induces less nausea than meperidine when administered parenterally.

The objective of our study is to identify and compare the prevalence of nausea after parenteral administration of opioids in the Emergency Department (ED). This prospective study utilized a convenience sample at a community-based ED with a volume of 60,000 annual visits. Patients who were in acute pain or had an exacerbation of chronic pain requiring treatment with an opioid analgesic agent were eligible. Demographic and historical features were recorded on a standardized closed data collection form. The main study endpoint was the occurrence of nausea. The prevalence of nausea and vomiting was compared between morphine and meperidine. There were 37 patients in the morphine group and 156 in the meperidine group. The two groups were similar with respect to mean age, gender, and weight. The reported nausea was 0 of 37 in the morphine group and 20 of 156 (12.8%) in the meperidine group. This difference between morphine and meperidine groups of 12.8% (95% confidence intervals 2-24%) was statistically significant. In our patient population, morphine caused significantly less nausea then meperidine when it was used as an analgesic in the ED.