DOUBLE-BLIND RANDOMIZED CONTROLLED TRIAL OF EFFECT OF METRONIDAZOLE ON PAIN AFTER DAY-CASE HEMORRHOIDECTOMY

Background Haemorrhoidectomy is commonly an inpatient procedure becaus e patients and doctors worry about postoperative pain. Day-case haemor rhoidectomy (DCH) is possible if patient anxiety is addressed and post operative pain and bower function are managed. Pain sometimes increase s a few days after haemorrhoidectomy, possibly because of secondary in fection. We studied the effect of metronidazole on pain after DCH, Met hods We randomly assigned 40 consecutive patients admitted for DCH met ronidazole 400 mg (n=20) or placebo (n=20) three times daily, both for 7 days. All patients received lactulose from 2 days before surgery fo r 2 weeks. Diathermy DCH was performed without pedicle ligature or ana l-canal dressing, and a diclofenac suppository was administered at the end of the procedure. Patients were discharged on the same day with d iclofenac, 0.2% glyceryl-trinitrate ointment, lactulose, a telephone n umber to call for queries in emergencies, and an outpatient appointmen t. Patients took paracetamol or Co-dydramol (dihydrocodeine and parace tamol) as required; they completed linear analogue charts every day an d completed questionnaires on satisfaction at 1 and 6 weeks. Findings 34 patients had all three major piles excised, of whom seven had addit ional division and reconstruction of the posterior skin bridge. Overal l, both groups of patients experienced less pain than expected, except on days 3 and 4. Patients in the metronidazole group had significantl y less pain than those in the placebo group on days 5, 6, and 7 (p=0.0 04, p=0.02, and p=0.006). Median time to return to work or normal acti vity was 15 days (range 12-28) in the metronidazole group and 18 days (7-34) in the placebo group (p=0.009). The patient satisfaction score was higher in the metronidazole group than in the placebo group at 1 w eek (p=0.005). Interpretation Prophylactic metronidazole in diathermy DCH suppressed secondary pain around days 5-7 and increased patient sa tisfaction and earlier return to work.