Description:
Racecadotril (CAS No.: 81110-73-8; also known as acetorphan) is a specific peripheral enkephalinase inhibitor and a first-line oral antidiarrheal drug with a unique mechanism of action distinct from traditional antidiarrheals (e.g., loperamide). It exerts its therapeutic effect by selectively inhibiting enkephalinase in the intestinal tract—without crossing the blood-brain barrier—thus protecting endogenous enkephalins from degradation. Endogenous enkephalins bind to opioid receptors in the intestinal mucosa, reducing hypersecretion of water and electrolytes (sodium, chloride) into the intestinal lumen, and normalizing intestinal fluid balance to alleviate diarrhea. Notably, racecadotril does not inhibit intestinal peristalsis, which avoids the common side effects of traditional antidiarrheals such as abdominal distension, constipation, and intestinal obstruction.Racecadotril is widely used in clinical practice for the symptomatic treatment of acute diarrhea in all age groups (infants, children, adults, and the elderly) due to its high efficacy, good tolerability, and broad applicability. Its detailed clinical uses and applicable scenarios are summarized below:
1. Primary Clinical Use: Symptomatic treatment of acute diarrhea (the core indication)
This is the main and most widely approved indication of racecadotril, covering all populations with acute non-invasive diarrhea:
Pediatric population (infants ≥1 month old, children): It is the first-choice drug for pediatric acute diarrhea recommended by many international clinical guidelines (e.g., WHO, European Society for Pediatric Gastroenterology, Hepatology and Nutrition). It effectively relieves the frequency of watery stools, reduces stool volume and water content, and shortens the course of acute diarrhea (viral, bacterial non-invasive, or functional). Unlike other antidiarrheals, it is safe for infants and young children with immature digestive systems and does not cause adverse reactions such as abdominal distension or constipation.
Adult population: For acute diarrhea caused by viral infections (e.g., norovirus, rotavirus), bacterial non-invasive infections, food intolerance, travel, or functional factors, racecadotril rapidly controls watery diarrhea symptoms, with a fast onset of action (therapeutic effect can be observed within 2 hours of administration). It is especially suitable for adults with acute diarrhea accompanied by large amounts of watery stools and risk of dehydration.
Elderly population: Given the high risk of dehydration and poor tolerance to anticholinergic/intestinal peristalsis-inhibiting drugs in the elderly, racecadotril is the preferred antidiarrheal due to its mild action, no effect on intestinal peristalsis, and low systemic adverse reactions, effectively managing acute diarrhea while reducing the risk of complications.
2. Adjuvant Clinical Uses
Racecadotril is also used as an adjuvant therapy for other types of diarrhea with intestinal hypersecretion as the main pathological feature, in combination with etiological treatment:
Traveler’s diarrhea: A common condition in travelers caused by intestinal pathogens (viruses, bacteria) in unfamiliar regions, characterized by acute watery diarrhea. Racecadotril rapidly alleviates diarrhea symptoms, improving the travel experience and reducing the risk of dehydration during travel.
Irritable Bowel Syndrome with Diarrhea (IBS-D): For patients with IBS-D whose main symptoms are recurrent watery diarrhea and abdominal pain, racecadotril is used as an adjuvant therapy to reduce stool frequency and water content, without aggravating abdominal distension (a common complaint in IBS-D patients), and is well-tolerated for long-term intermittent use.
Secretory diarrhea caused by cholera or enterotoxin-producing bacteria: Cholera and enterotoxin-producing E. coli cause severe watery diarrhea by inducing excessive intestinal secretion. Racecadotril, in combination with rehydration therapy and antibacterial drugs (for bacterial infections), effectively reduces intestinal fluid secretion, controls severe watery diarrhea, and shortens the duration of the disease.
Acute diarrhea in patients with chronic digestive system diseases: For patients with chronic gastritis, enteritis, or inflammatory bowel disease (in remission) who develop acute diarrhea due to infection or dietary factors, racecadotril is a safe adjuvant antidiarrheal that does not interfere with the normal digestive function of the intestinal tract and avoids worsening the underlying disease.
3. Key Application Characteristics in Clinical Practice
Racecadotril’s unique pharmacological properties make it stand out in antidiarrheal therapy, with the following critical application features that guide clinical use:
Targeted action: Selectively acts on the peripheral intestinal tract, no central nervous system effects (no drowsiness, dizziness, or opioid dependence), suitable for patients who need to maintain normal cognitive and motor functions (e.g., drivers, office workers, children).
Synergy with rehydration therapy: It is the first antidiarrheal that is highly recommended to be combined with oral rehydration salts (ORS)—the gold standard for diarrhea treatment by WHO. Racecadotril controls diarrhea symptoms while ORS replenishes water and electrolytes, forming a "symptom control + etiological support" combined therapy, which is the optimal treatment plan for acute diarrhea (especially in children and dehydrated patients).
Diverse dosage forms for all populations: It is formulated into age-adapted dosage forms, including oral granules (for infants and children, with adjustable dosage), hard capsules (for adults and older children), and oral solution (for patients with difficulty swallowing), which greatly improves medication compliance.
Low drug interaction risk: Its metabolic pathway is independent of the liver cytochrome P450 enzyme system, so it has no significant interactions with most common drugs (e.g., antibiotics, antacids, rehydration preparations), making it safe for combined use.
4. Important Usage Notes
Racecadotril is a symptomatic treatment drug, not an etiological drug, and its clinical use requires adherence to the following key principles:
It is not suitable for invasive diarrhea caused by invasive bacteria (e.g., Shigella, Salmonella) with severe symptoms such as high fever, bloody stools, and abdominal pain—etiological antibacterial treatment is the first choice in such cases, and racecadotril can be used as an adjuvant only after controlling the infection.
It should not be used for chronic diarrhea of unknown etiology; the underlying cause (e.g., inflammatory bowel disease, malabsorption syndrome) should be clarified first.
For patients with severe dehydration (e.g., oliguria, dry mucous membranes, altered mental status), intravenous rehydration is the priority, and racecadotril can be administered after the dehydration status is corrected.
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