A variety of medications can disrupt the lining of the gastrointestinal tract or cause GI complaints that can mimic certain conditions, such as inflammatory bowel disease and irritable bowel syndrome. Medications may produce these symptoms by altering GI physiology, increasing tissue toxicity, or interacting with the intestinal microbiota. From a clinical perspective, it may be helpful to distinguish between medication-induced GI symptoms and IBD or IBS in order to identify optimal treatment strategies.

For example, medications that may have an impact on the GI microbiome include antibiotics, proton pump inhibitors, and non-steroidal anti-inflammatory drugs. The GI microbiome consists of a large number of microorganisms associated with complex metabolic processes. A systematic review of the effect of antibiotics on the GI microbiome found that antibiotic use has been associated with dysbiosis of the microbiota. Antibiotics can negatively impact the beneficial diversity of the GI microbiome in both adults and children. The short-term GI effects of antibiotic use may include C. difficile infection, diarrhea, gastritis, bloating, intestinal pain, and compromised intestinal barrier function. Prolonged use of antibiotics has been associated with the development of antimicrobial resistance and IBS.

PPIs can be prescribed or taken over the counter and are used for the management of occasional or chronic heartburn. By suppressing gastric acid secretion, they may also impact the GI microbiota by reducing its diversity and leading to increased incidence of GI infections, such as those triggered by C. difficile, Salmonella, and Campylobacter. Prolonged use of PPIs has been associated with impaired nutrient absorption and an increased likelihood for H. pylori to colonize the stomach, which may lead to hypergastrinemia. NSAIDs comprise another class of medications that may impact the GI microbiome composition and the expansion of opportunistic bacteria through unintended toxicity. Gastrointestinal complaints associated with the use of NSAIDs include heartburn, reflux, dyspepsia, bloating, nausea, abdominal pain, diarrhea, constipation, ulcers, and gastrointestinal bleeding. 

Weight-loss medications, such as glucagon-like peptide-1 receptor agonists, work by mimicking the GLP-1 hormone, which is released by the gastrointestinal mucosa after consuming a meal and signals to the pancreas to produce more insulin, while suppressing glucagon secretion. A meta-analysis examining the effects of GLP-1 RAs reported associated GI disturbances, such as nausea, diarrhea, and vomiting. A study based on the FDA adverse event reporting system found that GLP-1 RAs were associated with increased risk of gastrointestinal system disorders including gastroesophageal reflux disease, nausea, diarrhea, vomiting, constipation, upper abdominal pain, gastritis, bezoar, breath odor, pancreatitis, and intra-abdominal hematoma.

Can nutrients support those with medication-induced GI complaints?

Certain amino acids, botanicals, functional foods, and minerals may offer support for GI health and function and help mitigate some of the GI effects associated with medications. 

• Glutamine is the most abundant free amino acid in the human body and it may play an important role in overall health as an intermediary in energy metabolism and glutathione, neurotransmitter, and nucleotide synthesis. In times of illness, glutamine may get significantly reduced as intestinal, immune, and renal cells utilize substantial amounts of it. In the GI tract, glutamine may play an important role in maintaining intestinal barrier function and supporting a healthy inflammatory response and intestinal cell proliferation and differentiation. 
• Mucins represent a family of glycoproteins secreted primarily by intestinal epithelial cells that may play an important role in mucosal protection and communication with external environments. They coat the intestinal lining and may help support the colonization of health‑promoting intestinal microbes, protect against epithelial cell injury, and serve as a lubricant to aid the passage of materials through the GI tract.
• Botanicals that may support the intestinal lining include mucilaginous nutrients, such as those found in okra, marshmallow, slippery elm, licorice, and aloe vera. These mucilaginous components may also contribute to the healing process of ulcerative conditions; support nutrient metabolism, healthy inflammatory response, and cellular health; display prebiotic effects and promote microbiome diversity and the production of short-chain fatty acids; hinder the adherence of H. pylori to the stomach lining; and exhibit antibacterial properties.
• N-acetyl-glucosamine is an amino sugar that supports GI function and immune health. Several species of the GI microbiome can release NAG into the intestinal lumen where it may support mucosal health in the GI lining, provide nutrients for commensal bacteria, and reduce biofilm formation of invasive strains. 
• Zinc L-carnosine is a form of zinc combined with the amino acid L-carnosine in a one-to-one ratio for increased bioavailability and absorption. It may stabilize the gut mucosa and membrane, help support gastric tissue integrity, promote healthy inflammatory response and antioxidant status, and support overall gastrointestinal function.
• Citrus pectin may support healthy inflammatory response, antioxidant status, and immune and cellular health. Oligosaccharides derived from citrus pectin, classified as nondigestible carbohydrates, may help support immunometabolism, healthy inflammatory response, and optimal GI microbiome composition and diversity, including the formation of health-supportive metabolites such as SCFAs.
• Prunes contain phytonutrients that may promote normal GI motility, regularity, microbiome diversity, and healthy bowel function, without the potential negative effects of harsh laxatives. They also contain high amounts of sorbitol and chlorogenic acid that may help maintain optimal gastric function.

Learn more about nutrients supporting GI health: 

Herbs and Botanicals for Optimal Gut Health

Deglycyrrhizinated Licorice in Promoting Gastric Mucosal Health

Zinc Carnosine for Gastric Mucosal Health

By Antonia Toupet, PhD