Rectal paracetamol has a significant morphine-sparing effect after hysterectomy

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