Relief of abdominal pain by morphine without altering physical signs in acute appendicitis

Abdominal pain is a common symptom among patients with acute appendicitis, yet these patients have long been denied relief from suffering because of widespread misconceptions associated with the use of opioids. We determined whether morphine hydrochloride masked the physical signs in adults with acute appendicitis and assessed the efficacy of morphine in relieving abdominal pain.

A prospective, double-blind, placebo controlled, clinical trial was conducted with 106 adult patients between 16 and 70 years old with acute appendicitis. Patients were randomly divided into a morphine group (n=54) or a normal saline group (n=52). All patients presented with acute abdominal pain with onset within 3 days. The morphine group received hypodermic injection of morphine (0.15 mg/kg; maximum 20 mg) and the control group members were given an equivalent volume of normal saline solution. The clinical symptoms, physical signs, and patients' cooperation during physical examination were assessed before and after 30 minutes of morphine or normal saline administration.

Abdominal pain was significantly relieved and the patients' cooperation was improved in the morphine group after 30 minutes treatment compared with the control group and before morphine administration (P<0.05). The physical signs were unaffected by either treatment (P>0.05).

Morphine relieved abdominal pain and improved the patients' cooperation for treatment and care. Furthermore, the morphine did not mask the physical signs of acute appendicitis.