STUDY OBJECTIVE: To evaluate the analgesic effects of the addition of epinephrine to a bupivacaine epidural infusion in early labor after a fentanyl bolus, following a lidocaine-epinephrine test dose. DESIGN: Randomized, double-blinded study. SETTING: Labor suite of a tertiary care hospital. PATIENTS: 60 ASA physical status 1 and 2, laboring, nulliparous women. INTERVENTIONS: All laboring women received a 3 mL epidural test dose of 1.5% lidocaine with 1:200,000 epinephrine, followed by a fentanyl 100 μg bolus in 10 mL of diluent volume. Patients were randomized to receive one of two continuous epidural infusions: bupivacaine 0.625 mg/mL at 10 mL/hr (control group) or bupivacaine 0.625 mg/mL with epinephrine 5 μg/mL at 10 mL/hr (epinephrine group). MEASUREMENTS: Time to re-dose, pain scores, and side effects were recorded. MAIN RESULTS: The mean duration of satisfactory analgesia prior to re-dose was 159 ± 62 min for the control group and 221 ± 111 min for the epinephrine group (P < 0.02). Pain scores were significantly higher in the control group than the epinephrine group at two time periods: 2.5 hours and 4.5 hours (P < 0.04). CONCLUSIONS: The administration of 0.625 mg/mL bupivacaine with epinephrine 5 μg/mL at 10 mL/hr, compared with plain 0.625 mg/mL bupivacaine at 10 mL/hr, provided a longer time to re-dose, decreased pain scores at two time intervals, and had no significant difference in duration of labor or side effects. Copyright © 2011 Elsevier Inc. All rights reserved.