Rectal acetaminophen does not reduce morphine consumption after major surgery in young infants

BACKGROUND: The safety and value of acetaminophen (paracetamol) in additionto continuous morphine infusion has never been studied in newbornsand young infants. We investigated the addition of acetaminophento evaluate whether it decreased morphine consumption in thisage group after major thoracic (non-cardiac) or abdominal surgery. METHODS: A randomized controlled trial was performed in 71 patients giveneither acetaminophen 90–100 mg kg^–1 day^–1orplacebo rectally, in addition to a morphine loading dose of100 µg kg^–1 and 5–10 µg kg^–1h^–1 continuous infusion. Analgesic efficacy was assessedusing Visual Analogue Scale (VAS) and COMFORT scores. Extramorphine was administered if VAS was 4. RESULTS: We analysed data of 54 patients, of whom 29 received acetaminophenand 25 received placebo. Median (25–75th percentile) agewas 0 (0–2) months. Additional morphine bolus requirementsand increases in continuous morphine infusion were similar inboth groups (P = 0.366 and P = 0.06, respectively). There wasno significant difference in total morphine consumption, respectively,7.91 (6.59–14.02) and 7.19 (5.45–12.06) µg kg^–1 h^–1for the acetaminophen and placebo group (P = 0.60). COMFORT[median (25–75th percentile) acetaminophen 10 (9–12)and placebo 11 (9–13)] and VAS [median (25–75thpercentile) acetaminophen 0.0 (0.0–0.2) and placebo 0.0(0.0–0.3)] scores did not differ between acetaminophenand placebo group (P = 0.06 and P = 0.73, respectively). CONCLUSIONS: Acetaminophen, as an adjuvant to continuous morphine infusion,does not have an additional analgesic effect and should notbe considered as standard of care in young infants, 0–2months of age, after major thoracic (non-cardiac) or abdominalsurgery.