Diphenoxylate
Diphenoxylate is a synthetic **opioid agonist** used primarily as an **antidiarrheal** agent. It is typically formulated with a sub-therapeutic dose of **atropine** (as co-phenotrope) to discourage abuse. > **Warning:** Use with caution in infectious diarrhea or toxigenic infections, as decreasing GI motility can delay the clearance of pathogens and toxins. **Clinical Pearl:** While historically used for acute diarrhea, modern veterinary medicine often prefers addressing the underlying cause or using probiotics/prebiotics, reserving motility modifiers for specific refractory cases.
Mecanismo: Diphenoxylate acts locally and centrally on **mu-opioid receptors** in the gastrointestinal tract. * **Increases** intestinal segmental smooth muscle tone. * **Decreases** the propulsive activity (peristalsis) of smooth muscle. * **Decreases** electrolyte and water secretion into the intestinal lumen. → The addition of **atropine** is at a sub-therapeutic dose to cause unpleasant anticholinergic side effects if overdosed, thereby discouraging abuse.
Vías de administración
Contraindicaciones
- Toxigenic diarrhea
- Infectious enteritis (e.g., Salmonella, Parvovirus)
- Obstructive GI disease
- Severe liver disease
- Cats (generally avoided due to CNS excitation/depression)
Efectos adversos
- Constipation
- Sedation
- Bloating
- Paralytic ileus
- CNS depression (especially in cats)
- Anticholinergic effects at high doses (dry mouth, tachycardia)
Interacciones farmacológicas
- Monoamine Oxidase Inhibitors (MAOIs) · May cause severe hypertensive crisis · major
- CNS Depressants (e.g., sedatives, anesthetics) · Additive CNS and respiratory depression · moderate
- Anticholinergics · Additive anticholinergic effects and increased risk of severe ileus · moderate
Monitorización
- Fecal output and consistency
- Bowel sounds (auscultation for ileus)
- CNS status (sedation or excitation)
Sobredosis
Overdose can lead to severe **CNS depression**, **respiratory depression**, and **paralytic ileus**. Due to the atropine component, anticholinergic signs (tachycardia, dry mucous membranes, mydriasis) may also occur. **Treatment:** Naloxone can be used to reverse the opioid effects. Provide supportive care for anticholinergic toxicity and respiratory depression.
La referencia de fármacos de VetSheet está destinada a veterinarios colegiados como apoyo a la decisión clínica, no sustituye el juicio profesional ni la ficha técnica vigente del fabricante.