Delayed Gastric Emptying in Functional Dyspepsia.

Functional dyspepsia is a complex syndrome with a poorly defined pathophysiology, resulting in uncertainties in its therapeutic approach. Abnormalities in gastrointestinal motility and sensitivity alone or combined seem to play a role in a substantial subgroup of patients. Drugs capable of prokinetic effects, such as antidopaminergics (eg, metoclopramide, domperidone, levosulpiride) and serotonin 5-HT4 receptor agonists (eg, tegaserod) can be potentially used in the treatment of dyspeptic patients. Furthermore, 5-HT4 receptor agonists do not appear to increase the gastric fundus tone which may also contribute to improved symptoms in subsets of patients. Alosetron, a 5-HT3 receptor antagonist, has been investigated mainly in irritable bowel syndrome, and the few studies performed in functional dyspepsia have provided conflicting results. Erythromycin and related derivatives, the motilides, represent another class of prokinetic compounds able to accelerate gastric emptying and potentially indicated in functional dyspepsia. The stimulatory effect on fundic tone and the occurrence of tachyphilaxis hamper the efficacy of these drugs in the long-term treatment. kappa-opioid receptor agonists might be useful for functional digestive syndromes because of their antinociceptive effects, but there are few available results and most are inconclusive. Results are also needed to prove efficacy of antidepressants (tricyclic agents and 5-HT reuptake inhibitors). Future clinical trials should be performed so that the formal structure required by good clinical practice can be adapted to detect significant effects in subgroups of patients with functional dyspepsia. Therapy should be ideally targeted to the different pathophysiologic abnormalities of these subgroups. The identification of the mechanisms leading to symptom generation should facilitate the development of newer and more effective therapeutic strategies in functional dyspepsia.