RACECADOTRIL IS A LIPOPHALIC DIESTERIFIED PRODRUG OF THE ENKEPHALINASE INHIBITOR THIORPHAN. IT HAS UNIQUE ANTISECRETORY PROPERTIES. ITS ACTION STARTS WITHIN 30 MTS.
ROTAVIRUS, BACTERIA, BACTERIAL TOXINS AND PARASITES ARE MAJOR CAUSES OF ACUTE DIARRHOEA IN BOTH CHILDREN AND ADULTS. RECENT STUDIES IN HUMANS AND ANTIMALS HAVE, HOWEVER, SUGGESTED THAT THESE AGENTS EVOKE FLUID AND ELECTROLYTE SECRETION BY ACTIVATION OF THE ENTERIC NERVOUS SYSTEM (ENS)
IN PERIPHARAL TISSUES, ORALLY ADMINISTERED RACECADOTRIL IS RAPIDLY HYDROLYSED TO THE MORE POTENT ENKEPHALINASE INHIBITOR THIORPHAN. WITHIN THESE TISSUES, MEMBRANE-BOUND ENKEPHALINASE ENZYMES DEGRADE ENDOGENOUS OPIOIDS (ENKEPHALINS). THIORPHAN (RACECADOTRIL) IS THOUGHT TO INHIBIT ENKEPHALINASE. BY INHIBITING THIS ENZYME, THIORPHAN (RACECADOTRIL) PREVENTS THE INACTIVATAION OF ENDOGENOUS ENKEPHALINS AND PROLONGS THEIR PHYSIOLOGICAL ACTION. THE ENKEPHALINS ACT AS NEUROTRANSMITTERS IN THE GASTROINTESTINAL TRACT BY ACTIVATING 8-OPIATE RECEPTORS AND THUS REDUCING THE LEVEL CYCLIC AMP. THE RESULT IS REDUCED SECRETION OF WATER AND ELECTROLYTES INTO THE INTESTINAL LUMEN WITHOUT ANY DETECTABLE EFFECT ON INTESTINAL MOTILITY. RACECADOTRIL HAS ANTISECRETORY ACTIONS ONLY WHEN HYPERSECRETION IS PRESENT, AND NOT IN THE BASAL STATE.