Prokinetics are a class of medications that enhance gastrointestinal (GI) motility by increasing the contractions of the stomach and intestines. These medications are used to treat a variety of conditions where there is slowed or impaired GI motility.
Metoclopramide (Reglan)
- Mechanism of Action:
- Metoclopramide works by blocking dopamine receptors in the upper GI tract. This action enhances the response to acetylcholine, a neurotransmitter that promotes GI motility, increasing the contractions of the stomach and accelerating gastric emptying.
- Uses/Considerations:
- Gastroparesis: Helps manage delayed gastric emptying.
- GERD: Enhances esophageal motility and improves acid clearance.
- Nausea and Vomiting: Effective for nausea and vomiting due to various causes, including chemotherapy and postoperative recovery.
- Side Effects:
- Extrapyramidal symptoms (e.g., tardive dyskinesia)
- Drowsiness and fatigue
- Diarrhea
Domperidone (Motilium)
- Mechanism of Action:
- Domperidone blocks peripheral dopamine receptors, which enhances the release of acetylcholine in the GI tract. This increases gastric motility and accelerates gastric emptying with fewer central nervous system side effects compared to metoclopramide.
- Uses/Considerations:
- Gastroparesis: Useful for delayed gastric emptying and related symptoms.
- Nausea and Vomiting: Effective for managing nausea, particularly when associated with GI conditions.
- Side Effects:
- Headache and dizziness
- Dry mouth
- Rarely, cardiac arrhythmias
Cisapride (Propulsid)
- Mechanism of Action:
- Cisapride enhances the release of acetylcholine by stimulating serotonin receptors in the gut, which promotes peristalsis throughout the GI tract and accelerates gastric emptying.
- Uses/Considerations:
- Gastroparesis: Treats delayed gastric emptying and improves related symptoms.
- Severe GERD: Used for severe cases to enhance esophageal and gastric motility.
- Side Effects:
- Serious cardiac arrhythmias (QT prolongation)
- Restrictions on use due to safety concerns
Erythromycin
- Mechanism of Action:
- Erythromycin acts as a motilin receptor agonist. It mimics the action of motilin, a hormone that stimulates gastric contractions, promoting gastric emptying and increasing GI motility.
- Uses/Considerations:
- Gastroparesis: Used off-label to improve gastric emptying, particularly in diabetic patients.
- Postoperative Ileus: Helps stimulate motility and prevent postoperative ileus.
- Side Effects:
- Gastrointestinal disturbances (nausea, vomiting, abdominal pain)
- Antibiotic resistance with prolonged use