Objective To compare the effectiveness of paracetamol, hyoscine butylbromide and the combination of paracetamol plus hyoscine butylbromide (paracetamol + hyoscine butylbromide) in the management of patients with acute undifferentiated abdominal pain attending the emergency department (ED).

Setting A large teaching hospital with an annual ED census of 120 000 adult patients.

Methods A prospective, randomised placebo controlled trial of a convenience sample of patients attending the ED. The trial compared the analgesic effect of intravenous hyoscine butylbromide, oral paracetamol and the combination of both drugs using a Visual Analogue Scale pain scoring tool. Rescue analgesia was administered when pain was inadequately controlled by trial medication.

Results 132 patients were recruited to the trial. At 30 min, all analgesic combinations produced significant similar levels of pain relief. At 60 min after administration of the trial medication, mean reductions in pain scores for patients receiving paracetamol only were significantly greater than those receiving paracetamol + hyoscine butylbromide (ANCOVA model, p=0.0180). No relationship was seen between treatment arm and the need for rescue analgesia (χ², p value=0.846).

Conclusion The trial data suggest that oral paracetamol is at least as effective as intravenous hyoscine butylbromide and a combination of both drugs in the management of acute undifferentiated abdominal pain presenting to the ED. Based on these results and factors such as cost and tolerability, we recommend single agent paracetamol as the agent of choice for the management of acute mild to moderate undifferentiated abdominal pain.

Trial registration number MHRA Ref: 19717/0226/001-0001; European Clinical Trials Database. EUDRAct No: 2006-005395-40.