Information to Guide Pharmacist Counseling About Diabetic Gastroparesis and its Impact on Glycemia
There’s a good chance your diabetic patients don’t know that high blood glucose can cause gastroparesis. As they experience gas, bloating and nausea, they’ll simply take an OTC product and figure something they ate didn’t agree with their system. This can be dangerous, because they could be well on the way to irreversible autonomic nerve damage and persistent gastroparesis.
Pharmacists represent the first chance for many patients to learn about diabetic gastroparesis. Whether you have the opportunity to reach out as they buy OTC medicines or they’re established diabetic patients you counsel about prescription medications, make sure they know to never ignore common GI symptoms.
Diabetic Gastroparesis and its Impact on Glycemia
While the definition of gastroparesis is straightforward—delayed gastric emptying in the absence of mechanical obstruction—several significant questions about the condition remain unanswered. Most notably, experts acknowledge that there’s a poor correlation between delayed gastric emptying, symptom patterns, and response to therapy, according to a study in the November 2015 issue of Current Opinion in Gastroenterology.1 Diabetic gastroparesis is part of this conundrum, as poor glycemic control is a risk factor for gastroparesis, yet getting blood glucose under control doesn’t necessarily improve gastric emptying.
The pathophysiological mechanisms underlying diabetic gastroparesis aren’t fully understood, but researchers know that diabetes-induced damage to the vagus nerve and oxidative stress are causative factors. At the cellular level, diabetic gastroparesis is characterized by loss of interstitial cells of Cajal (ICC), which work as pacemakers that stimulate muscle contraction.
Prevalence statistics are hard to pin down due to nonspecific symptoms and various assessment methods used to report incidence. In spite of the variables, here’s a rundown of the information currently available:
- Estimated prevalence ranges from 1 percent up to 65 percent.2
- Diabetic gastroparesis usually develops 10 years after diagnosis of diabetes—this likely explains a higher prevalence in those with type 1 diabetes.
- Incretin therapy increases the risk for gastroparesis.3
The impact of gastroparesis on glycemia is a two-way street. Long-term and acute hyperglycemia slow down gastric emptying and high HbA1c levels are associated with gastrointestinal symptoms. At the same time, gastroparesis has a detrimental effect on glycemic control. Delayed gastric emptying leads to erratic and difficult-to-predict blood glucose levels, which makes it hard to maintain steady levels and interferes with optimal insulin administration.
Symptoms and Dietary Treatment
Think about how you’d feel if food sat in your stomach for a longer-than-normal amount of time and you can well imagine the classic yet generic symptoms of diabetic gastroparesis:
- Abdominal pain
- Early satiety
- Postprandial fullness
- Gastroesophageal reflux
Out of all the symptoms, the degree of nausea or vomiting correlates most closely with the severity of the patient’s gastroparesis. Abdominal pain isn’t associated with disease severity, but it is an under-appreciated symptom that predicts quality of life. Various studies report that 72 to 90 percent of patients experience abdominal pain and it’s a dominant symptom in 18 percent. In many patients, the pain is present daily, interferes with sleep, and increases the risk for psychological disorders.
Dietary management: Even though medical therapy may be prescribed, long-term management of gastroparesis-related symptoms requires dietary adjustments. Since diet is also an essential key to blood glucose management, patients with diabetic gastroparesis should consult with a registered dietitian or a diabetic specialist to be sure they develop a sustainable and healthy diet plan. A few changes that can help relieve gastroparesis include:
Avoid foods and beverages that slow digestion:
- High fat
- High fiber
- Greasy, fried foods
- Carbonated beverages
Change eating and postprandial habits:
- Eat slowly – take time to chew food
- Eat smaller meals – try consuming six smaller meals
- Sit upright and/or take a walk after eating
Many may find that individual foods in each category trigger symptoms, while others don’t, so they may not need to eliminate entire categories. Some patients get significant symptom relief from a small-particle-size diet.4 This type of diet consists of pureed foods or foods that are easy to mash into small pieces with a fork, which means patients can’t eat foods that are stringy or have peels, membranes, seeds, or grains, such as tomatoes, nuts, and whole grains. The downside is that most people don’t want to eat smashed or soft foods all the time and restricting fiber and whole grains goes against the premise of diets designed to control glycemia.
Medical Therapy for Diabetic Gastroparesis
The top priority is to establish and maintain tight blood glucose levels, a task that can be a challenge in patients with diabetic gastroparesis and may require more frequent glucose testing and a change in insulin dosing or scheduling. Beyond glycemic control, hydration and electrolytes must be assessed and restored if necessary. Additional medical treatment may include any of the following:
- Metoclopramide – Prescribed at the lowest dose and for no longer than 12 weeks due to the risk of extrapyramidal side effects.
- Domeperidone – Second-line treatment but associated with the risk of sudden cardiac death.
- Erythromycin and azithromycin – Used only when metoclopramide and domeperidone fail to relieve symptoms. They work as motilin agonists but their effectiveness diminishes after about four weeks.
Emerging treatments: Novel medications in clinical trials as of August 2016 offer hope for more effective treatment options with fewer adverse effects:5
- Camicinal – A motilin agonist in a phase II, 4-week clinical study in type 1 and type 2 diabetic gastroparesis.
- Relamorelin – A ghrelin agonist in a phase II, 4-week study in patients with type 1 diabetes.
- Velusetrag – 5-HT4 receptor agonist undergoing clinical trials in patients with gastroparesis.
Proactive Outreach Promotes Early Diagnosis
Patients may consult their physician if their gastrointestinal symptoms are severe or if symptoms persist too long, but they’re more likely to seek help sooner when they know that generic GI symptoms may be a red flag for poorly controlled blood glucose. Pharmacists can help improve their long-term health and overall quality of life through proactive patient education about diabetic gastroparesis.
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- “Gastroparesis,” November 2015, https://www.ncbi.nlm.nih.gov/pubmed/26406565 ↩
- “A Review of Diabetic Gastroparesis for the Community Pharmacist,” December 2016, https://www.uspharmacist.com/article/a-review-of-diabetic-gastroparesis-for-the-community-pharmacist ↩
- “Epidemiology, Mechanisms, and Management of Diabetic Gastroparesis,” January 2011, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3035159/ ↩
- “A Small Particle Size Diet Reduces Upper Gastrointestinal Symptoms in Patients with Diabetic Gastroparesis: A Randomized Controlled Trial,” March 2014, https://www.ncbi.nlm.nih.gov/pubmed/24419482 ↩
- “Novel Diet, Drugs, and Gastric Interventions for Gastroparesis,” August 2016, http://www.medscape.com/viewarticle/868462_1 ↩