Which pair of medications is cited as prokinetic options to increase motility?

• A. Metoclopramide and erythromycin
• B. Cisapride and metoclopramide
• C. Domperidone and erythromycin
• D. Loperamide and metoclopramide

Answer: (A)

Prokinetic medications work by boosting the gut’s ability to move contents forward, either by increasing gastric contractions or by enhancing the migrating motor complex that sweeps the intestines. Metoclopramide does this by blocking dopamine D2 receptors in the gut (and in the vomiting center), which removes an inhibitory signal and raises acetylcholine activity, thereby strengthening peristalsis and accelerating gastric emptying. It also has some 5-HT4 activity that supports this effect. Erythromycin, though an antibiotic, acts on motilin receptors to mimic the body's natural motilin signal, triggering strong, coordinated contractions that promote gastric emptying and small-bowel propulsion. Together, these two are classic prokinetic options used to increase motility in conditions like gastroparesis and ileus.

The other options include agents that either slow motility or are limited in use due to safety or regulatory reasons. Loperamide reduces gut movement rather than increasing it. Cisapride is a prokinetic but has be restricted because of safety concerns (notably serious QT prolongation). Domperidone can be prokinetic in some settings but is not universally available or recommended due to safety considerations.