Gastroparesis medications — a plain-language guide

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Two different jobs

The medicines used for gastroparesis fall into two big groups that do very different jobs. Mixing them up is one of the most common sources of confusion — and it changes how you judge whether something is "working."

Movers vs. soothers

A prokineticA medicine that speeds up the movement of the digestive tract, helping the stomach empty faster. actually tries to fix the problem — it nudges a sluggish stomach to empty faster. An antiemeticA medicine that reduces nausea and vomiting. It calms the "feeling sick" signal but does not speed up emptying. does something else entirely — it quiets the nausea, but the stomach still empties just as slowly as before.

Analogy — the mover

Picture a kitchen sink draining slowly. A prokinetic is like clearing the drain so the water finally goes down. It works on the actual problem — the slow emptying itself.

Analogy — the soother

Nausea is like an alarm going off. An antiemetic switches the alarm off, which is a real relief. But the alarm was only the signal — turning it off doesn't speed the stomach up, so the slow emptying is still there underneath.

See the difference

Turn each medicine on and watch what changes. Notice that "ease the nausea" calms the meter without changing how the stomach empties.

Stomach

Stomach emptying

Nausea

Right now: emptying is slow, nausea is high.

Why this matters for the wider family

Gastroparesis is the main event here, but it lives in a family of motilityHow well the muscles of the digestive tract squeeze and move food along. Poor motility means things move too slowly. problems sometimes called digestive tract paralysisAn umbrella term for conditions where part of the gut moves too slowly, including gastroparesis, chronic intestinal pseudo-obstruction, and colonic inertia.. Some of the medicines on the next pages actually target further downstream — the intestines and colon — rather than the stomach. We'll flag those clearly so it's obvious what's for gastroparesis and what's for a related condition.

Prokinetics

Getting things moving

These are the "movers" — medicines meant to help a slow stomach empty. Only one is actually FDA-approved specifically for gastroparesis; the others are borrowed from elsewhere and used off-labelWhen a doctor prescribes an approved medicine for a use the FDA hasn't formally approved it for. This is legal and common, but the evidence can be thinner..

Reglan (metoclopramide) Prokinetic FDA-approved for GP

What it is: The only medicine FDA-approved specifically for gastroparesis in the US. It both speeds emptying and calms nausea, which is unusual.
How you take it: By mouth as a tablet, dissolving tablet, or liquid, usually before meals. Also available as an injection in hospital.
What it does: Blocks dopamine to make the stomach contract more strongly and empty faster, while also quieting the brain's nausea center.
Common effects: Drowsiness, restlessness, fatigue; sometimes anxiety or low mood.
Warnings: Can cause extrapyramidalMovement side effects from dopamine-blocking drugs — muscle stiffness, restlessness, or involuntary movements. movement effects. Your doctor sets the dose based on your kidney function, age, and other medicines.

Black box warning

Long-term use can cause tardive dyskinesiaA movement disorder — often permanent — causing uncontrollable movements, usually of the face. There is no known cure. Risk rises the longer you take the drug., a movement disorder that may be permanent and has no known treatment. It's uncommon — but the risk rises the longer you take the drug and the more you take, which is why treatment is generally limited to 12 weeks. This is a safety limit, not a target dose.

Motegrity (prucalopride) Prokinetic Off-label for GP

What it is: Approved for chronic constipation, used off-label for gastroparesis. Evidence in gastroparesis is mixed.
How you take it: One tablet by mouth once a day.
What it does: Activates serotonin (5-HT4) receptorsSerotonin "docking points" in the gut wall. Switching them on triggers the muscles to contract and move contents along. in the gut to stimulate movement. It's a pure mover — no direct effect on nausea.
Common effects: Headache, abdominal pain, nausea, diarrhea, especially early on.
Warnings: Prescribing information notes watching for new low mood or thoughts of self-harm. For adults only.

Domperidone (Motilium) Prokinetic Not FDA-approved

What it is: Used widely in other countries, but not approved in the US. It works like Reglan but causes fewer brain-related side effects because it mostly stays out of the brain.
How you get it: In the US, only through the FDA's Expanded Access programA special FDA pathway ("compassionate use") that lets certain severely affected patients access a non-approved drug when standard treatments have failed. — a strict process for patients 12+ who've failed other treatments. Note: the FDA has said the expanded-access supply was set to end after September 2025, so availability is uncertain.
What it does: Blocks dopamine to speed emptying and reduce nausea.
Common effects: Generally milder day-to-day effects than Reglan; dry mouth, headache.
Warnings: Can affect heart rhythm.

Serious cardiac risk

Domperidone can cause QT prolongationA change in the heart's electrical timing that can trigger a dangerous, sometimes fatal, irregular heartbeat. and, rarely, sudden cardiac events — the main reason it isn't approved in the US. Risk is higher at higher doses and in people over 60. Use involves ECG and blood monitoring.

Erythromycin (Ery-Tab, E.E.S., EryPed) Prokinetic Off-label for GP

What it is: An old antibiotic that, at low doses, happens to be the strongest stomach-emptying stimulant of the group. It's used for the emptying effect, not to fight infection.
How you take it: By mouth (often a liquid, to allow small doses) before meals, or by IV in hospital for flare-ups.
What it does: Mimics motilinA natural gut hormone that triggers the "housekeeping" waves which sweep the stomach clean between meals., a hormone that triggers strong stomach contractions.
Common effects: Cramping, nausea, abdominal pain.
Warnings: Can affect heart rhythm (QT prolongation) and interacts with many other drugs. Long-term use risks antibiotic resistance.

Analogy

Erythromycin is like a spring that loses its bounce with constant pressing — the body gets used to it and it stops working as well (called tachyphylaxisWhen a drug's effect fades after repeated use as the body adapts. With erythromycin, the "movement" receptors get turned down.). Doctors often work around this with "drug holidays," using it in short stretches rather than continuously.

Linzess (linaclotide) Downstream — the colon

What it is: The odd one out. Linzess isn't a stomach mover or a nausea soother — it works lower down, in the intestines and colon, for constipation-type conditions like colonic inertiaA form of severe, slow-transit constipation where the colon's muscles don't move waste along normally.. It belongs to the wider motility family, not gastroparesis itself.
How you take it: One capsule by mouth once a day, on an empty stomach.
What it does: A secretagogueA medicine that draws fluid into the intestine, softening stool and helping it move along. — it pulls fluid into the gut to get things moving through the lower digestive tract.
Common effects: Diarrhea is the most common, and can be severe.
Warnings: Not for people with a suspected bowel blockage.

Black box warning

Linzess is never for children under 2 — in the very young it can cause life-threatening dehydration.

Antiemetics

Easing the nausea

These are the "soothers." They don't speed up emptying — they turn down the nausea and vomiting so day-to-day life is more livable. They're often used alongside a mover.

Zofran (ondansetron) Antiemetic

What it is: A widely used anti-nausea medicine. The Zofran brand is largely gone from US pharmacies; the generic ondansetron is what's usually dispensed.
How you take it: Tablet, dissolving tablet, liquid, or IV.
What it does: Blocks serotonin (5-HT3) receptorsThe serotonin signals that trigger the brain's vomiting reflex. Blocking them dials down nausea. that trigger the vomiting reflex. It does not change how fast the stomach empties.
Common effects: Headache, fatigue, and — worth noting for this community — constipation, which can be a real problem when your gut is already sluggish.
Warnings: Can cause QT prolongation (heart-rhythm changes), especially at high IV doses — the 32 mg IV dose was pulled for this reason. Rarely, it contributes to serotonin syndrome when combined with other serotonin drugs.

Meclizine (Antivert, Bonine) Antiemetic

What it is: An antihistamine best known for motion sickness and vertigo. It plays a smaller, more occasional role in gastroparesis, for the dizziness-and-queasiness type of nausea.
How you take it: Tablet or chewable by mouth.
What it does: Blocks histamine (and has an anticholinergicBlocks acetylcholine, a nerve-signal chemical. Causes dry mouth, blurred vision, and drowsiness; can also slow the gut. effect) to settle the balance-and-nausea pathways.
Common effects: Drowsiness, dry mouth, blurred vision.
Warnings: Its anticholinergic effect can slow the gut further and is used cautiously in older adults.

Promethazine (Phenergan) Antiemetic

What it is: A strong, sedating anti-nausea medicine used when milder options aren't enough.
How you take it: Tablet, liquid, rectal suppository, or injection.
What it does: Blocks histamine and dopamine signals involved in nausea and vomiting.
Common effects: Marked drowsiness, dry mouth; sometimes restlessness or movement effects.
Warnings: Can be strongly sedating, especially when you first start — for many people this eases over the first days as the body adjusts. Take extra care with driving early on, and with combining it with alcohol or other sedatives.

Black box warnings (two)

1. Never for children under 2 — it can cause fatal breathing suppression. 2. Given by IV, it can cause severe tissue and blood-vessel injury, including gangrene, if it leaks or hits an artery.

Reference

Glossary

Plain-language definitions for the terms used throughout this guide.

GastroparesisA condition where the stomach empties too slowly, without a blockage causing it.Like a sink draining at a trickle even though nothing's stuck in the pipe.

MotilityHow well the muscles of the digestive tract squeeze and move food along.The "conveyor belt" of your gut running at full speed vs. barely creeping.

ProkineticA medicine that speeds up gut movement to help the stomach empty.A drain cleaner for a sluggish pipe.

AntiemeticA medicine that reduces nausea and vomiting without changing emptying.Silencing the smoke alarm rather than clearing the smoke.

Digestive tract paralysisAn umbrella term for conditions where part of the gut moves too slowly.A family of "slow-traffic" problems along the same road.

Colonic inertiaSevere slow-transit constipation where the colon doesn't move waste along.The far end of the conveyor belt grinding to a halt.

Off-labelUsing an approved medicine for a purpose the FDA hasn't formally approved.Using a butter knife as a screwdriver — it works, but it's not what the label says.

Black box warningThe FDA's strongest safety warning on a medicine's label.The bold, boxed "read this first" note on the package.

Tardive dyskinesiaOften-permanent involuntary movements, usually of the face, from long dopamine-blocking use.A movement "glitch" that can't easily be switched back off.

QT prolongationA change in the heart's electrical timing that can trigger a dangerous rhythm.The heart's metronome slipping out of time.

TachyphylaxisWhen a drug's effect fades with repeated use as the body adapts.A spring that stops bouncing when you keep pressing it.

MotilinA gut hormone that triggers strong "housekeeping" contractions between meals.The signal that sweeps the kitchen floor after everyone's eaten.

SecretagogueA medicine that pulls fluid into the intestine to get things moving.Adding water to help a stuck load slide down the chute.

Expanded Access (IND)An FDA pathway to a non-approved drug for patients who've run out of options.A special-permission door when the standard doors are closed.

AnticholinergicBlocks a nerve-signal chemical; causes dry mouth, drowsiness, and can slow the gut.A dimmer switch on several body signals at once.

Extrapyramidal effectsMovement side effects — stiffness, restlessness, involuntary movements — from dopamine-blocking drugs.The body's "movement wiring" getting crossed signals.

About this guide

Written in plain language from the primary sources below — mainly US FDA prescribing information and the FDA's own domperidone pages, plus current gastroparesis management guidance. It describes what medicines do and what to watch for; it does not give doses, because the right dose depends entirely on the individual and is set by a physician. Last reviewed July 2026.

Sources

Metoclopramide (Reglan) — boxed warning for tardive dyskinesia and the 12-week limit: FDA prescribing information.
Promethazine — boxed warnings for respiratory depression in children under 2 and severe tissue injury with IV use: FDA labeling; NEJM summary of the pediatric warning.
Linaclotide (Linzess) — boxed warning, contraindicated under age 2 (serious dehydration); mechanism and common effects: DailyMed label.
Ondansetron (Zofran) — QT-prolongation warning and withdrawal of the 32 mg IV dose: FDA Drug Safety Communication.
Prucalopride (Motegrity) — 5-HT4 agonist, approved for chronic constipation, off-label in gastroparesis: FDA prescribing information.
Domperidone — not FDA-approved; Expanded Access (IND) only; cardiac risk; supply notice: FDA: Information about domperidone; FDA: How to request domperidone.
Erythromycin as a prokinetic, tachyphylaxis and drug holidays; overall drug-selection context: AGA 2025 Guidelines for the Management of Gastroparesis.

Links go to third-party sites (FDA, DailyMed, NEJM, and clinical guidance) and were current at the time of writing. Prescribing information is updated periodically; your pharmacist or physician has the most current version.