Erythromycin is a macrolide antibiotic used as a prokinetic in dogs and cats. It is most often used as a second-line promotility agent to aid in gastric emptying in conjunction with metoclopramide, but it may be used alone. Care should be taken to avoid drug-drug interactions via the cytochrome P450 enzyme system.
Mechanism of Action/Pharmacokinetics
- Erythromycin’s promotility effects are not completely understood, but, at low doses, it is suspected to be due to binding to motilin and serotonin (5-HT3) receptors. Once bound, it stimulates contractions in the stomach and intestines by activating the migrating motility complexes and antegrade peristalsis.
- Erythromycin also increases lower esophageal pressure. Additionally, erythromycin is reported to stimulate colonic activity in dogs.
- Combination therapy with metoclopramide has been shown to be more efficacious than therapy with either agent alone.