From the Guidelines
Yes, erythromycin acts on the motilin receptor.
Mechanism of Action
- Erythromycin, a macrolide antibiotic, interacts with motilin receptors in the gut, potentiating gastric and small bowel motility, increasing lower oesophageal sphincter pressure, and influencing colonic transit and gall bladder function 1.
- This prokinetic effect is utilized therapeutically in conditions characterized by reduced GI motility, such as diabetic gastroparesis, anorexia nervosa, and colonic pseudo-obstruction 1.
Clinical Use
- Erythromycin is used as a prokinetic agent, especially for short-term use due to the development of tachyphylaxis 1.
- The recommended dose for erythromycin in treating gastrointestinal dysmotility is 900 mg/day 1.
- Azithromycin may be more effective for small bowel dysmotility, and combining erythromycin with octreotide may have a beneficial effect in some cases 1.
The FDA Drug Labels for erythromycin (PO) do not address this question.
From the Research
Erythromycin and Motilin Receptors
- Erythromycin has been shown to act as a motilin agonist by binding to motilin receptors on gastrointestinal smooth muscle 2.
- The binding of erythromycin to motilin receptors stimulates gastrointestinal motility, which can be useful in treating gastrointestinal motility disorders 3.
- Studies have demonstrated that erythromycin can increase the amplitude of antral contractions and improve gastroduodenal coordination, leading to accelerated gastric emptying 2.
Mechanism of Action
- Erythromycin stimulates ileal motility by activating dihydropyridine-sensitive calcium channels, which is independent of the intrinsic nervous and opiate systems 4.
- The contractile response to erythromycin is mediated by direct contraction of smooth muscle via the influx of extracellular Ca2+ 5.
- Erythromycin's action on motilin receptors can also modulate vagal nerve pathways involved in emesis, demonstrating anti-emetic activity at low doses 6.
Therapeutic Applications
- Erythromycin has been shown to normalize delayed gastric emptying in patients with diabetic, idiopathic, and postvagotomy gastroparesis 3.
- The substance may also be useful in treating gastroesophageal reflux disease, gastritis, pathological overgrowth of the small intestine, hypokinesia of the gallbladder, and chronic obstipation 3.
- Human motilin receptor-expressing transgenic mice have been used to study the mechanisms of the gastric motor response to human motilin and erythromycin, providing a useful model for evaluating motilin receptor agonists as gastric prokinetic agents 5.