Gastroparesis: Helping Patients Cope

Pharmacists can be a fundamental educational resource for patients with gastroparesis, which is also called delayed gastric emptying.

Gastroparesis, also referred to as delayed gastric emptying, is a syndrome that decreases the ability of the stomach to empty in the absence of an obstruction.¹ Gastroparesis affects more than 1.5 million individuals in the United States, with approximately 100,000 individuals suffering from a severe type of the disorder.² Unfortunately, standard medical therapy is often ineffective in relieving symptoms in approximately 30,000 of these patients.² This condition is often challenging for many patients and can negatively affect their overall quality of life.

As one of the most accessible health care professionals, pharmacists can be a fundamental educational resource for patients with gastroparesis. Pharmacists can not only counsel patients about their medications but also educate them about gastroparesis.

Causes and Risk Factors

While the exact cause of gastroparesis is unknown, research suggests that it may result from a disruption of nerve signals to the stomach.^1,2 Gastroparesis can be classified as idiopathic, diabetic, or postsurgical. ^3-5 Most cases appear to be idiopathic, representing an estimated 64% of cases; diabetic gastroparesis accounts for 31% of cases.³ Postsurgical gastroparesis is often the result of vagus nerve injury.^3-4

Diabetes is the most commonly recognized medical condition associated with gastroparesis.^3,5,6 According to the American Diabetes Association, gastroparesis can exacerbate diabetes by making it more difficult to control the blood glucose level. One of the most vital treatment goals for diabetic gastroparesis is to maintain tight glycemic control.⁶

Other causes of gastroparesis include certain types of infections, hypothyroidism, scleroderma, autoimmune conditions, neuromuscular diseases, eating disorders, and certain cancers.^3-5 Individuals with eating disorders (ie, anorexia nervosa or bulimia) may be at greater risk for developing gastroparesis.^3-5 Normal gastric emptying may resume and symptoms may improve when food and caloric intake are sufficient.^3,4

Several pharmacologic agents may delay gastric emptying.^1,3-5 The drugs most commonly associated with gastroparesis are narcotics and certain antidepressants^1,3,4,7; other agents are listed in Table 1^1-5,7. Patients with drug-related gastroparesis, also referred to as pseudogastroparesis, show signs of improvement when the causative medication is discontinued.^3-5

Symptoms

Patients with gastroparesis may present with a variety of symptoms, including bloating, nausea, early satiety, postprandial fullness, heartburn, and epigastric pain.^1-5 Research indicates that symptoms may be caused by the ingestion of solid, fatty, or high-fiber foods, or carbonated drinks.^1-5,7 Nausea and vomiting are very common in patients with gastroparesis, and some patients may vomit undigested foods several hours after eating.⁷ Patients may present with noticeable weight loss due to poor absorption of nutrients or inadequate caloric intake.^1-5,7

Treatment

The goals of therapy include improvement of symptoms, glycemic control, and gastric emptying, with minimal adverse effects, as well as enhancement of the patient’s quality of life.^4,8 Therapy typically includes dietary modifications, the use of medications that aid in accelerating gastric emptying, nonpharmacologic measures, and psychological therapies.^3,4,9 Dietary modification is considered to be the first line of therapy in patients with mild gastroparesis.^3,4,9

In January 2013, the American College of Gastroenterology (ACG) released its updated recommendations regarding the evaluation and management of patients with gastroparesis. According to the ACG, the management of gastroparesis should include the assessment and modification of diet, relief of symptoms, enhancement of gastric emptying, and maintenance of tight glycemic control in diabetic patients.^4,10

Medical therapy typically involves the use of prokinetic and antiemetic therapies. ^3,4,7,10 Currently approved treatments include metoclopramide and gastric electrical stimulation.^4,7,10 To date, metoclopramide is the only FDA-approved medication for the treatment of gastroparesis. Metoclopramide should be used for no longer than 12 weeks unless the therapeutic benefit outweighs the potential adverse effects.^1,3,4,7,10 Metoclopramide should be prescribed at the lowest possible effective dose.^4,7,10 It exerts its pharmacologic effect by stimulating stomach muscle contractions to aid in gastric emptying.^4-7,10 Patients should be advised to take medication 20 to 30 minutes before meals and at bedtime.⁴ The FDA has issued a black-box warning on metoclopramide because of the risk of adverse effects such as tardive dyskinesia.^4,7,10 During counseling, patients should be advised that use of metoclopramide may cause restlessness, insomnia, and depression.^4,7,10

According to the ACG guidelines, other medications that may be prescribed include domperidone, short-term use of erythromycin, and centrally acting antidepressants.^1,3,4,7,10 A summary of ACG recommendations regarding pharmacological therapy can be found in Online Table 2^{3,4,7,8,10-12}.

Table 2: Pharmacologic Therapy for Gastroparesis: Summarized Recommendations

1. In addition to dietary therapy, prokinetic therapy is recommended to improve gastric emptying and the symptoms associated with gastroparesis, taking into account the benefits and risks of treatment. (Strong recommendation; moderate level of evidence)

2. Metoclopramide is considered the first line of prokinetic therapy and should be prescribed at the lowest effective dose in a liquid formation to facilitate absorption. The risk of tardive dyskinesia has been estimated to be <1%. Patients should be advised to discontinue therapy if adverse effects develop, such as involuntary movements. (Moderate recommendation; moderate level of evidence)

3. For patients unable to tolerate or use metoclopramide, domperidone can be prescribed because it has investigational new drug clearance from the FDA. It has been shown to be as effective as metoclopramide in reducing symptoms without the propensity for causing central nervous system adverse effects. Given the propensity for domperidone to prolong a corrected QT interval on an electrocardiogram, a baseline electrocardiogram is recommended and treatment withheld if the corrected QT is >470 ms in male patients and 450 ms in female patients. A follow-up electrocardiogram during treatment with domperidone is also advised. (Moderate recommendation; moderate level of evidence)

4. Erythromycin improves gastric emptying and symptoms of gastroparesis. Administration of intravenous (IV) erythromycin should be considered when IV prokinetic therapy is warranted in hospitalized patients. Oral treatment with erythromycin also improves gastric emptying. However, the long-term effectiveness of oral therapy is limited by tachyphylaxis. (Strong recommendation; moderate level of evidence)

5. Treatment with antiemetic agents should be administered to improve associated nausea and vomiting, but this treatment will not improve gastric emptying. (Conditional recommendation; moderate level of evidence)

The use of tricyclic antidepressants can be considered for refractory nausea and vomiting associated with gastroparesis, but these agents will not improve gastric emptying and may even retard it. (Conditional recommendation; low level of evidence)

Adapted from references 3, 4, 7, 8, 10-12.

Because gastroparesis can often result in inadequate nutrition and therefore vitamin and mineral deficiencies, the dietary goals depend on the severity of the disease.⁹ In some patients, carbonated beverages should be avoided or limited because the release of carbon dioxide may exacerbate gastric distention.^4,10,13,14 Patients should be advised to avoid consumption of alcohol and smoking of tobacco, both of which can affect gastric emptying.^15-17 In diabetic patients, the goals of therapy include achieving tight glycemic control via diet and hypoglycemic medications, when warranted, because improvement of the blood glucose level may accelerate gastric emptying.^6,11,12 In some cases, patients who are unable to tolerate foods may require a feeding jejunostomy tube, which bypasses the stomach.¹⁸ Some common dietary recommendations for managing gastroparesis can be found in Online Table 3^{3,4,9,12,19,20.}

Table 3: Recommended Dietary Modifications

Obtain support from a nutritionist/dietician.

Eat small low-fiber, low-fat meals 4 to 5 times a day.

Avoid excess fat in meals.

Eat small-particle meals; particles ≥2 mm tend to empty slowly.

Avoid excess dietary fiber.

Use supplementary liquid meal replacement products when warranted.

Adapted from references 3, 4, 9, 12, 19, and 20.

Living with Gastroparesis

While there is no cure for gastroparesis, research on treating it is ongoing. Several resources are available to help patients understand and manage this chronic condition (Online Table 4). The use of the following is being investigated: serotonin- receptor agonists, a ghrelin agonist, a cholecystokinin-receptor antagonist, and next-generation gastric electrical stimulators.^3,21-24 Currently, a new ghrelin agonist in a subcutaneous injection is undergoing FDA clinical trials, and researchers are investigating the use of intranasal metoclopramide; both studies are showing some promising results.²⁴ More information about ongoing clinical trials can be found at http://clinicaltrials. gov/ct2/results?term=gastroparesis& Search=Search.

Table 4: Educational Resources on Gastroparesis

American College of Gastroenterology website: www.gi.org

American Diabetes Association website: www.diabetes.org

International Foundation for Functional Gastrointestinal Disorders website: www.iffgd.org

Because gastroparesis can be challenging to manage, pharmacists can be an important source of information and encouragement for patients. Patients with diabetic gastroparesis may need to take insulin more frequently and check their blood glucose level more frequently, as determined by a primary health care provider.²¹ Diabetic patients should be reminded to maintain tight glycemic control.

Patients with gastroparesis should be encouraged to adhere to the recommended treatment plan, including the selected dietary guidelines and medications. They should be urged to maintain routine medical examinations by their primary health care provider. Patients should be advised to consult their primary health care provider if their symptoms worsen or if they experience any adverse effects from the prescribed therapy.

Although gastroparesis is a chronic condition that can negatively affect an individual’s overall well-being and quality of life, pharmacists can increase awareness about this condition, educate patients, and stress the importance of patient adherence to help patients take control of their health and effectively manage gastroparesis.

Ms. Terrie is a clinical pharmacist and medical writer based in Haymarket, Virginia.

References

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