prokinetic
A prokinetic is like a coach urging the digestive tract to keep things moving forward. When the stomach empties too slowly or the gut is sluggish, a prokinetic strengthens and coordinates its contractions so food and fluid travel along as they should.
Most prokinetics work by tuning the chemical messengers that drive gut muscle. Metoclopramide and domperidone block dopamine D2 receptors, which removes a brake on motility and speeds gastric emptying; metoclopramide also has serotonergic actions. Serotonin 5-HT4 agonists (such as prucalopride) stimulate motility further along the bowel. Several of these drugs double as antiemetics because the same receptors sit in the vomiting pathway.
Prokinetics help conditions like delayed gastric emptying (gastroparesis), reflux and functional dyspepsia, but their effects are modest and use is often time-limited. The dopamine-blocking agents carry the most concern: metoclopramide can cause movement disorders, especially in the young and elderly, while domperidone is largely kept out of the brain but can affect the heart's QT interval.
A patient with diabetic gastroparesis takes metoclopramide before meals to help the stomach empty more promptly.
Metoclopramide blocks dopamine D2 receptors to accelerate gastric emptying.
Because some prokinetics block dopamine receptors in both the gut and the brain, drug-induced movement disorders are a recognised risk, especially with prolonged metoclopramide use.