Which agent slows intestinal motility

Cisapride may be especially useful in managing chronic constipation in cats with megacolon; in many cases, it alleviates or delays the need for subtotal colectomy. Cisapride is also useful in managing cats with hairball problems and in dogs with idiopathic megaesophagus that continue to regurgitate frequently despite a carefully managed, elevated feeding program.

In comparative studies of GI motility in people and animals, cisapride is clearly superior to other treatments. Initially, the only adverse effects reported in people were increased defecation, headache, abdominal pain, and cramping and flatulence; cisapride appeared to be well tolerated in animals.

As cisapride became widely used in management of gastroesophageal reflux in people, cases of heart rhythm disorders and deaths were reported to the FDA. These cardiac problems in people were highly associated with concurrent drug therapy or specific underlying conditions.

In veterinary medicine, adverse reactions to clinical use of cisapride have not been reported. Cisapride for animals can only be obtained through compounding veterinary pharmacies. Domperidone is a peripheral dopamine receptor antagonist that has been marketed outside the USA since It is available in Canada as a mg tablet.

Domperidone regulates the motility of gastric and small-intestinal smooth muscle and has some effect on esophageal motility. It appears to have very little physiologic effect in the colon. It has antiemetic activity from dopaminergic blockade in the CRTZ. But because very little domperidone crosses the blood-brain barrier, reports of extrapyramidal reactions are rare; however, if a reaction occurs, the treatment is the same as for reactions to metoclopramide.

Domperidone failed to enhance gastric emptying in healthy dogs in one study. In other studies, however, domperidone was superior to metoclopramide in stimulating antral contractions in dogs but not cats, and it improved antroduodenal coordination in dogs. Because of its favorable safety profile, domperidone appears to be an attractive alternative to metoclopramide. Macrolide antibiotics , including erythromycin and clarithromycin, are motilin receptor agonists.

They also appear to stimulate cholinergic and noncholinergic neuronal pathways to stimulate motility. At microbially ineffective doses, some macrolide antibiotics stimulate migrating motility complexes and antegrade peristalsis in the proximal GI tract.

Erythromycin has been effective in the treatment of gastroparesis in human patients in whom metoclopramide or domperidone was ineffective.

Erythromycin increases the gastric emptying rate in healthy dogs, but large food chunks may enter the small intestine and be inadequately digested.

Erythromycin induces contractions from the stomach to the terminal ileum and proximal colon, but the colon contractions do not appear to result in propulsive motility. Therefore, erythromycin is unlikely to benefit patients with colonic motility disorders. Human pharmacokinetic studies indicate that erythromycin suspension is the ideal dosage form for administration of erythromycin as a prokinetic agent.

Other macrolide antibiotics have prokinetic activity with fewer adverse effects than erythromycin and may be suitable for use in small animals. Both erythromycin and clarithromycin are metabolized by the hepatic cytochrome P enzyme system and inhibit the hepatic metabolism of other drugs, including theophylline, cyclosporine, and cisapride. Nonantibiotic derivatives of erythromycin are being developed as prokinetic agents. Ranitidine and nizatidine are histamine H 2 -receptor antagonists that are prokinetics in addition to inhibiting gastric acid secretion in dogs and rats.

Their prokinetic activity is due to acetylcholinesterase inhibition, with the greatest activity in the proximal GI tract. Cimetidine and famotidine are not acetylcholinesterase inhibitors and do not have prokinetic effects.

Chlorpromazine, Promethazine. Causes: Diabetes Medications Incretin Mimetic s e. Exenatide , Liraglutide Pramlintide Symlin. Images: Related links to external sites from Bing. Related Studies. Trip Database TrendMD. Related Topics in Pharmacology. Gastroenterology Chapters. In most instances, increasing the rate of gastric emptying and gastro-intestinal motility increases the rate of absorption of a drug but, for digoxin and riboflavin, increased gastrointestinal motility is associated with a decrease in the rate of absorption.

Delayed drug absorption due to altered gastric emptying usually results in therapeutic failure, especially if the drug has a short biological half-life. At present it is not possible to predict accurately the magnitude and clinical relevance of all drug absorption interactions.