Objective: To compare the efficacy and tolerance of acetorphan, an orally active enkephalinase inhibitor whose antidiarrhoeal properties derive from a purely antisecretory activity, to that of octreotide, a subcutaneously administered somatostatin analogue, in the treatment of refractory diarrhoea in AIDS patients.
Design: An open randomized crossover trial.
Setting: The inpatient medical units of three hospitals.
Patients: Thirteen adult inpatients with AIDS and refractory diarrhoea that lasted for 35 +/- 8 weeks despite use of traditional antidiarrhoeal agents and was characterized by 7.0 +/- 1.2 stools/day, weighing 1033 +/- 174 g/day with a lipid output of 18.8 +/- 3.5 g/day.
Interventions: Acetorphan (100-300 mg thrice daily) and octreotide (50-150 micrograms thrice daily) were given in random order during two 1-week periods.
Main outcome measures: Response was defined as a reduction by at least one-third of both daily stool number and weight.
Results: The mean daily stool number was reduced to 4.6 +/- 1.1 with acetorphan (P < or = 0.05) but was 5.6 +/- 1.2 with octreotide (NS). Whereas two patients responded to both treatments, two responded to acetorphan alone and one to octreotide alone. Daily lipid output in faeces was reduced non-significantly with acetorphan (11.5 +/- 2.3 g) but was nearly doubled with octreotide (33.7 +/- 12.0 g). Acetorphan was very well tolerated.
Conclusion: Enkephalinase inhibitors may be a useful alternative to somatostatin analogues in the management of refractory diarrhoea in AIDS.