This transcript has been edited for clarity.
Hello. I'm Dr David Johnson, professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia. Welcome back to another Viewpoints.
Today's discussion aims to provide a good overview of best practices for the management of gastroparesis.
This is a fairly common condition in our patient population. Over 5 million adults in the United States are described as having gastroparetic-like symptoms. Not all of them have gastroparesis; some have overlap with functional dyspepsia.
Recently, two excellent examples of medical education on gastroparesis have been published. The first of these comes from Dr Michael Camilleri, the "godfather" of gastrointestinal motility, who offers a review of treatments beyond metoclopramide. The second are recommendations on managing medically refractory gastroparesis from the American Gastroenterological Association, which were authored by Drs Brian Lacy, Jan Tack, and C. Prakash Gyawali, all experts in the field of motility. I wanted to combine highlights from these two publications and offer some of my own perspectives.
Defining Refractory Gastroparesis
The definition of gastroparesis requires exclusion of both obstruction and concomitant medications that may mitigate against gastroparetic conditions. In terms of medications, we're talking about glucagon-like peptide 1 agonists used for diabetes, opiates, and anticholinergics. They may also delay gastric emptying.
After excluding these possible causes, we must consider associated diseases.
A disease like diabetes goes hand-in-hand with gastroparesis and is frequently correlated with peripheral neuropathy. I always ask about peripheral neuropathy when I'm talking to someone with diabetes and suspected gastroparesis.
Seeing food in the stomach may not have the predictability for diagnosing gastroparesis that you might ascribe to it, unless there is an underlying condition such as diabetes. Even in instances where the patient has been fasting, that may not be absolute. That's why it's so important to make sure you're excluding these other things we just discussed.
When it comes to defining gastric emptying abnormalities, the consensus is that you must use a gastric emptying test.
The field of gastric emptying has evolved over the past several decades, and the cornerstone recommendation is to now use a test that goes on for at least 4 hours. This will reflect what your institution does, but the typical number among centers of excellence is that more than 25% retention at 4 hours is generally consistent with a diagnosis of gastroparesis.
As it relates to managing gastroparesis, the overriding principle is to focus on food first.
Dr Camilleri makes the excellent point that you should start patients on a small-particle diet. I also tell my patients to incorporate a soft-cooked, low-fat diet and to consume small-sized meals.
Additionally, I have them avoid late postprandial recumbency owing to an aspiration risk.
If they experience symptoms that are exacerbated on any given day, I have them go to liquids. Liquids go through much more quickly than solids.
Gastroparetic conditions are more vagotonic. When you eat foods, you lose that elasticity and distensibility of the stomach, and also passive relaxation. But liquids will splash through because the stomach is more nontonic and more rigid, so it accelerates the emptying into the areas where the food can then transit out very quickly.
Methods for Using Metoclopramide
Metoclopramide is the only drug approved for gastroparetic conditions in the United States, though the tablet formulations are not without issues.
We're always concerned about the neurologic side effects, particularly the risk for tardive dyskinesia. More recent data indicate that these risks are seemingly less than previously reported — around 1.7 per 100,000 for neurologic side effects and 0.14 per 100,000 for tardive dyskinesia.
Although these are a lot lower than in earlier reports, I nonetheless have my patients recognize that these are reported side effects. This is a big medical malpractice issue, with lawyers still advertising about it.
In the United States, the use of metoclopramide is approved for 12 weeks, which almost makes no sense when talking about a chronic, relapsing condition. But metoclopramide has a tachyphylaxis effect.
Dr Camilleri makes a great point about using a 7- to 10-day window where you put the patient on more liquids or a blenderized diet, stop the metoclopramide for a bit, and let them re-equilibrate.
Liquid metoclopramide may also be an option you can use to stick to a lower dose.
Again, remember that solids go through less quickly, and the same would be true of the tablet formulation of this medication. The dose of liquid metoclopramide is often 5-10 mg three times a day, which allows you to potentially get by with a lower dose using that splash-through effect as it goes through the stomach.
There are also off-label medications that are not approved by the US Food and Drug Administration (FDA).
Clearly, domperidone is used by a lot of us. Patients can get this drug from Canada, but you also can apply for it under the FDA's Expanded Access to Investigational Drugs program. This is something that patients need to be aware of, if they're choosing not to use this program but going through an out-of-country prescriber instead.
I always tell my patients that because this is not an FDA-approved drug, it will not show up on drug-drug interactions. So, when they get a new prescriber and medication, they must alert them that they're on a drug that may have some drug-drug interactions, particularly the QT interval.
We will not even provide the drug if the baseline electrocardiogram (EKG) shows that the QT interval is > 470 msec for males or > 450 msec for females. After performing that baseline EKG, we then require an EKG at least yearly and a visit every 6 months. These are my best practice recommendations, and not necessarily from these most recent articles. Make sure that you document the use of a non–FDA-approved drug, and that they take time out for drug-drug interactions.
Domperidone is something that is traditionally given at a dose of 10-20 mg three times a day, 30-60 minutes before meals and at bedtime.
I always put my patients with gastroparesis on bed elevation with a bed wedge owing to the aspiration risk. That's 100% of the time.
Prucalopride is a drug that we use more for the treatment of chronic constipation, but there is some limited data as it relates to gastroparesis. These come from a fairly small study with 28 idiopathic patients and six diabetic patients with gastroparesis. It showed that prucalopride was effective at improving gastroparetic-like symptoms but not necessarily gastric emptying.
I always tell my patients when they have gastroparesis, "If you feel like you're slipping and you can't keep up, go to liquids only." Liquids keep you hydrated. Hydration keeps you from ketosis. Ketosis keeps you from getting more nausea and vomiting, and then you get more dehydrated and more ketotic.
There are other considerations if the patients are hospitalized. If they are admitted, it's typically with what's deemed acute refractory gastroparesis. Erythromycin at 1.5-3 mg/kg can be given intravenously over an hour every 8 hours.
You can use neostigmine, which we sometimes do in Ogilvie syndrome and colonic pseudo-obstruction, but you have to give it in relation to EKG monitoring. We give this intramuscularly as opposed to intravenously, which we use in acute Ogilvie syndrome. We have atropine available if they start to get bradycardia.
If these patients are experiencing primary nausea, don't dismiss the option of using antiemetics. Ondansetron or some of the other antiemetics are very helpful.
The caveat, however, is not to use marijuana and other cannabinoid receptor agonists. We use dronabinol in some of our patients with cancer. Yet these may delay gastric emptying, so I warn my patients not to use this off-the-cuff because it could make things worse. We certainly see THC-related cannabinoid hyperemesis in some patients.
If pain is the predominant symptom, take a step back, because the diagnosis of gastroparesis should be questioned. Opioids should never be used in this circumstance. Neuromodulators can be used, including selective serotonin reuptake inhibitors and traditional tricyclics. However, we must recognize that some of these drugs, particularly tricyclics, do have an anticholinergic effect, which may decelerate gastric emptying.
Botulinum toxin injections are another option that's been studied for the past two decades. The randomized controlled trials have not shown that it accelerates emptying. Again, this is something that is not recommended.
Surgical pyloroplasty is fairly radical for these patients, but it has been used and shown to be effective.
More recently, there has been interest in gastric peroral endoscopic myotomy (G-POEM), which is extrapolated from what we do in the esophagus. This is something that seems promising in trials. Data are better than what we see with gastric stimulation studies and comparable to those in pyloroplasty. But we have no sham-controlled studies, and while serial studies are supportive, we must be cautious.
If you're going to choose this, make sure that (1) the patient is well-characterized at baseline and afterward, and (2) you send them to a center of excellence that is using established analytical approaches and selection criteria before they decide to use G-POEM. Also, do not ever use this as a default for primary therapy.
Overall, we have a critical need for sham therapies. We have an evolving set of possible options for novel therapies, but we're stuck with metoclopramide and domperidone as our old therapies. Be aware of those and understand some of the new potential caveats and recommendations for best practice.
Hopefully, these best-practice strategies will steer you well in your next interaction with a very perplexing and frustrating complex of symptoms.
I'm Dr David Johnson. Thanks for listening.
David A. Johnson, MD, a regular contributor to Medscape, is professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia, and a past president of the American College of Gastroenterology. His primary focus is the clinical practice of gastroenterology. He has published extensively in the internal medicine/gastroenterology literature, with principal research interests in esophageal and colon disease, and more recently in sleep and microbiome effects on gastrointestinal health and disease.
Medscape Gastroenterology © 2022 WebMD, LLC
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: David A. Johnson. A How-To Guide for Managing Gastroparesis - Medscape - Apr 01, 2022.