Rectal paracetamol has a significant morphine-sparing effect after hysterectomy

We have evaluated the morphine-sparing effect of rectal paracetamol duringthe first 24 h after abdominal hysterectomy in a placebo- controlled,double-blind study. We studied 72 patients receiving patient-controlledanalgesia (PCA) with i.v. morphine after a standardized anaesthetic,allocated randomly to receive rectal paracetamol 1.3 g, diclofenac 50 mg orplacebo, after wound closure and at 8 and 16 h. Suppositories were blindedby the hospital pharmacy. Study violations excluded data from sevenpatients. Patient data, morphine doses during anaesthesia and recovery, andsedation and nausea scores were comparable. Mean morphine consumptionduring PCA was 35.0 (SD 20.4) mg, 32.7 (27.4) mg and 54.9 (28.3) mg in theparacetamol (n = 24), diclofenac (n = 20) and placebo (n = 21) groups,respectively (P < 0.05). Morphine sparing during PCA for paracetamol anddiclofenac (36% vs 40% over 24 h) was significant from 4 h. Global scoresof average pain over 24 h were lower after diclofenac compared withparacetamol (P < 0.01) and placebo (P = 0.08). We conclude that rectalparacetamol was an efficacious adjuvant analgesic after regular dosing.