Guidelines for the use of orexigenic drugs in long-term care.

Undernutrition is defined as a state induced by nutrient deficiency that may be improved solely by administration of nutrients. By this definition, provision of adequate protein and energy sources should reverse the clinical presentation and correct the problem. However, a large number of patients who seem to be undernourished fail to respond to refeeding. A developing understanding of the acute-phase inflammatory response to illness and the role of cytokines in the pathophysiology of chronic illness has challenged the current diagnostic paradigm of undernutrition. In the presence of adequate food, weight loss is most often due to cytokine-associated cachexia and anorexia. Failure of appetite, or anorexia, may play a role in involuntary weight loss. Intervention for involuntary weight loss should aim first at the provision of adequate calories and protein, often in the form of high-density nutrition supplements. However, cytokine-mediated cachexia is remarkably resistant to hypercaloric feeding. With continued weight loss, the use of an orexigenic drug should be considered. Orexigenic drugs have been demonstrated to improve appetite and produce weight gain. The mechanism is unknown but may relate to suppression of proinflammatory cytokines. General guidelines for the use of orexigenic agents are presented. Although much work remains to be done, anticytokine drugs seem to be a promising avenue for the treatment of involuntary weight loss.