Subarachnoid meperidine (pethidine) causes significant nausea and vomitingduring labor

Background: The combined spinal-epidural (CSE) technique using bupivicaine- fentanyl has become an established method of pain control during parturitio n, One limitation is the relatively short duration of effective analgesia p roduced by bupivicaine-fentanyl. In contrast, subarachnoid meperidine has b een shown to provide a long duration of anesthesia in nonobstetric patients , Therefore, the authors tested the hypothesis that subarachnoid meperidine produces a significant increase in the duration of analgesia compared with bupivicaine-fentanyl. Methods: Based on a power analysis of preliminary data, the authors intende d to recruit 90 patients for the study, randomized to three groups: 2.5 mg bupivicaine-25 mu g fentanyl, 15 mg meperidine, or 25 mg meperidine, Howeve r, after enrolling 34 patients, the study was discontinued because of a sig nificant increase in nausea or vomiting in the study patients. Results: Nausea or vomiting was substantially increased in both meperidine groups compared with the bupivicaine-fentanyl group: 16 with nausea or vomi ting in the meperidine groups (n = 21), compared with 1 in the bupivicaine- fentanyl group (n = 11), P = 0.0011. The mean duration of analgesia provide d by 25 mg meperidine was 126 +/- 51 min, compared with 98 +/- 29 min for b upivicaine-fentanyl and 90 +/- 67 min for 15 mg meperidine, These data were not significant (P = 0.27). Conclusions: Although intrathecal meperidine could potentially prolong suba rachnoid analgesia during labor, its use was associated with a significant incidence of nausea or vomiting. These data do not support the use of subar achnoid meperidine in doses of 15 or 25 mg for labor analgesia.