Evidence of Clinical Benefits from the Predominant Spinal Action of Bolus-Dose Epidural Fentanyl

To the Editor: Ginosar et al. (1) provided evidence that epidural fentanyl acts predominantly at spinal sites if administered as a bolus and at supraspinal sites if administered as an infusion. In our clinical practice, we have found bolus administration of epidural fentanyl to be very effective. Twelve studies were quoted in the paper that support a spinal action for epidural fentanyl. In another study, which was not referred to, we found that following cesarean section, patient-controlled bolus doses of epidural fentanyl produced lower rest and dynamic pain scores than IV fentanyl (2). We also found that patient-controlled bolus doses of epidural fentanyl, which provided more effective rest and dynamic pain relief than IV morphine, were associated with less nausea, and with less drowsiness, than IV morphine (3). Because of this, we routinely offer patient-controlled epidural fentanyl as an alternative to IV morphine to women who have had a cesarean section and have an epidural catheter in situ. Our experiences with patient-controlled bolus doses of epidural fentanyl add further weight to the findings of Ginosar et al. (1). They also provide evidence of clinical benefits from its predominant spinal action: improved analgesia, with a reduction in central side effects. David W. Cooper, MD Consultant Anaesthetist James Cook University Hospital Middlesbrough, Cleveland United Kingdom