LoperamideDose, contraindications and adverse effects for Cats and Dogs.

Peripherally restricted opioid receptor agonist; slows intestinal motility without significant CNS opioid effects at normal doses. Loperamide is used as a GI motility modifier in small animal species (primarily dogs) with noninfectious, intractable diarrhea. Some have found that loperamide is useful for treating or helping to reduce chemotherapy-induced (eg, toceranib) diarrhea in dogs. In combination with maropitant, loperamide may be useful in preventing paclitaxel-induced GI adverse effects in dogs. Anecdotally, lo

Loperamide acts on the circular and longitudinal muscles by binding to mu-opioid receptors in the GI tract to decrease GI motility and excessive GI propulsion. Loperamide also decreases intestinal secretion induced by the cholera toxin, prostaglandin E2, and diarrhea caused by factors in which calcium is the second messenger (noncyclic AMP/GMP mediated).

Loperamide is contraindicated in patients with known hypersensitivity to it. Loperamide is a P-glycoprotein substrate that is contraindicated in dogs that are homozygous (MDR1 mutant/mutant) for the MDR1 genetic mutation (also known as ABCB-1delta) due to loss of P-glycoprotein function needed to excrete loperamide from the CNS.

In dogs, salivation, constipation, bloat, and sedation are the most likely adverse effects encountered when recommended dosages are used. Potentially, paralytic ileus, toxic megacolon, pancreatitis, and CNS effects (eg, sedation, ataxia) could be seen. Dogs with the MDR1 genetic mutation (also known as ABCB-1delta; MDR1 mutant/mutant) can develop severe CNS depression, ataxia, mydriasis and salivation after receiving a single 0.1 mg/kg PO dose of loperamide.

■ Clinical efficacy ■ Hydration and serum electrolytes especially in cases of severe diarrhea ■ Adverse CNS effects (eg, sedation, depression, disorientation, ataxia, mydriasis, non-reactive pupils)