Diarrhoea: a significant worldwide problem.

Diarrhoea is a problem, not only of the developing world, but also of the Western world. However, the economic implications of diarrhoeal diseases are particularly evident in the poorer countries. The most common worldwide cause of diarrhoea is intestinal infection and infants, pre-school children, the elderly, and those with congenital or acquired immunodeficiency run a high risk of contracting such infections. Diarrhoeal disease can be classified into three major clinical syndromes: acute watery diarrhoea, bloody diarrhoea, and persistent diarrhoea. A number of different micro-organisms can cause infectious diarrhoea, depending on the clinical setting. The development of oral rehydration solution has provided a simple approach to rehydration and maintenance of hydration in patients with acute watery diarrhoea, and has been implemented worldwide under the auspices of the World Health Organization. However, rehydration does not treat the diarrhoea itself, which will persist until the infection resolves. Since the drugs currently used for the treatment of diarrhoea, such as the opiate agents and antibiotics, have limitations, the search continues for a drug that acts predominantly on secretory pathways without affecting gastrointestinal motility. Novel therapeutic approaches include 5-HT(2) and 5-HT(3) receptor antagonists, calcium-calmodulin antagonists, and sigma-receptor agonists. Another approach has concentrated on the antisecretory role of the neurotransmitter, enkephalin, and has resulted in the development of the enkephalinase inhibitor, racecadotril. This drug has true antisecretory activity, and has demonstrated good efficacy and tolerability in clinical trials.