Pain Relief and Side Effects in Intravenous Remifentanil and Iintramuscular Meperidine

Introduction:  Although there no agreement about best way for relieving  pain in delivery, finding an appropriate method with the lowest pain and drug dose and side effect shoud be considered. The aim of this study is to compare the analgesic efficacy and side effects of Remifentanil and Meperidine as two methods of pain relieving in obstetrics during an uncomplicated labor.

 Materials and Methods: Fourty full term parturient with singleton pregnancy and vertex presentation were randomized to receive either Remifentanil (0.5µg/kg every 4 min, IV) or Meperidine (50 mg, IM) at the beginning of active labor phase. A visual analog scale (VAS) was used to assess the severity of pain. Also maternal and fetal side effects were assessed.

Results: The pain scores were lower in Remifentanil group at 60 min after analgesia (P<0.0001) and during the first stage of labor (P<0.0001) than Meperidine group. The pain scores in second stage of labor were also lower in Remifentanil group (P=0/013). 95% of women rated analgesia as good to excellent in Remifentanil group as compared with 35% in Meperidine group (P<0.0001). Prolonged labor in first stage was rare in the both groups and there were no significant differences between them. Side effects such as sedation, nausea and vomiting and respiratory depression and decreasing hemoglobin oxygen  and saturation were rare and no significant differences were seen between groups. Also no significant differences were seen between groups from mode of delivery or neonatal outcomes.

Conclusion: The results indicated that for controlling delivery pains Remifentanil is better than Meperidine and side effects were uncommon and adequate continuous monitoring decrease maternal side effects.