Efficacy of subarachnoid meperidine for labor analgesia.

Meperidine is an opioid agonist with known weak local anesthetic properties. To determine the efficacy of subarachnoid meperidine as a labor and delivery analgesic, 20 term parturients were given 10 mg meperidine via continuous spinal catheter. Visual analog pain scores on a ten-point scale and patient satisfaction scores on a four-point scale were measured before and after establishment of the block and one hour after maximum block was achieved. Time to pain relief and return of pain was recorded. Additional doses of 7 mg meperidine were given subarachnoid via the catheter when patients requested additional analgesia. Follow-up assessment 24 hours postpartum was used to determine overall patient satisfaction. Visual analog pain scale scores (mean +/- SD) were 8.57 +/- 1.43 before block, 0.62 +/- 0.89 immediately after block, and 0.33 +/- 0.57 at one hour after block (p less than 0.0001). Patient satisfaction scale scores (mean +/- SD) were 0.83 +/- 0.88 before block, 3.90 +/- 0.37 immediately after block, and 3.85 +/- 0.31 at one hour after block (p less than 0.0001). At follow-up, 14 of 18 patients rated satisfaction as excellent, with the remaining 4 rating it as good. Expulsive efforts were excellent in 14, good in 3, and fair in 1; 2 patients had cesarean sections. Mean time to onset of pain relief was 3.9 minutes (range, 2-12), with analgesia lasting a mean of 83 minutes (range, 38-180). Two patients developed slight motor block. Side effects appeared insidiously and are similar to those observed with other neuraxial opioids.