Gastrointestinal Drug Interactions Affecting the Elderly

Mandeep Singh, MDb, Shawn Chaudhary, MDb, Sadra Azizi, MDa and Jesse Green, MDb∗,     aAlbany Medical Center, Albany, NY, USA; bDivision of Gastroenterology, Albany Medical Center, Albany, NY, USA

∗Corresponding author.

With the burgeoning elderly population in the United States, drug interactions are an increasing concern because of altered drug metabolism associated with age and polypharmacy. This article describes interactions between drugs used in common gastrointestinal diseases, including acid peptic disease, diarrhea, constipation, endoscopic procedural sedation, and inflammatory bowel disease, and those used to treat 5 common geriatric primary care diseases: hypertension, diabetes, hyperlipidemia, arthritis, and psychiatric illnesses.

Keywords

Drug interactions

Geriatrics

Common gastrointestinal conditions

Inflammatory bowel disease

Acid peptic disease

Diarrhea

Constipation

Endoscopic procedural sedation

Key points

• This article investigates common interactions between drugs used to treat common geriatric primary care diseases and those used in common gastrointestinal diseases, including acid peptic disease, diarrhea, constipation, endoscopic procedural sedation, and inflammatory bowel disease.

• The predicted exponential growth of elderly patients will create challenging medical management and logistical problems for clinicians.

• This article emphasizes the need for physicians to be vigilant regarding potential drug interactions in a geriatric population burdened with polypharmacy and comorbid conditions.

Introduction

The United States is undergoing a dramatic shift in demographics. In 2011, people aged 65 years or older accounted for 41.4 million people, or 13.3% of the American population. Since 2000, the elderly population has increased disproportionately to the general population, by 18% versus 9.4%, respectively. Additionally, the number of Americans aged 45 to 64 years who will reach 65 years over the next 2 decades will increase by 33%. By 2030, approximately 72.1 million elderly people will be living in the United States. This exponential growth of elderly patients will create challenging medical management and logistical problems for clinicians.

With the burgeoning elderly population in the United States, drug interactions are an increasing concern because of altered drug metabolism associated with age and polypharmacy. The assessment of drug interactions requires understanding of various age-related factors and issues. This article describes interactions between drugs used in gastrointestinal diseases and those used in geriatric primary care diseases. The Lexi-Comp and Epocrates databases were used to analyze possible interactions between various medication classes. PubMed searches were also performed to evaluate recent literature discussing the relationship between common gastrointestinal diseases in the elderly and comorbidities.1–6

Drugs used in acid peptic diseases

Elderly patients with severe esophagitis (defined as Los Angeles grade C or D) are at high risk for the development of Barrett esophagus and esophageal adenocarcinoma. Gastroesophageal reflux disease (GERD) in the elderly population often presents with characteristic symptoms, including burning chest discomfort and dysphagia, but may present with uncommon symptoms, including atypical chest pain, severe nausea, and odynophagia. Studies in the elderly population with GERD and esophagitis have shown greater inconsistencies in symptoms as they relate to endoscopic disease severity. In a study of 12,000 patients aged 18 to 75 years with endoscopically documented erosive esophagitis, severe heartburn was seen in 30% of elderly patients aged 70 years or older compared with 47% of younger patients aged 31–40 years. Among these patients, severe esophagitis (defined as Los Angeles grade C or D) was seen in 35% of the elderly patients versus 25% of the younger patients (Figs. 1 and 2).7–9

Fig. 1 The prevalence of severe esophagitis and severe heartburn by age decade cohort. (Data from Johnson DA, Finnerty MB. Heartburn severity underestimates erosive esophagitis severity in elderly patients with gastroesophageal reflux disease. Gastroenterology 2004;126:660–4.)

Fig. 2 The prevalence of severe esophagitis by age decade cohort among patients with severe heartburn. (Data from Johnson DA, Finnerty MB. Heartburn severity underestimates erosive esophagitis severity in elderly patients with gastroesophageal reflux disease. Gastroenterology 2004;126:660–4.). Email: greenj@mail.amc.edu

Drug classes used in acid peptic disease include antacids, H2 blockers, proton pump inhibitors, and sucralfate. Each of these agents works by a different mechanism to alter disease process. Lexi-Comp and Epocrates databases were used to analyze interactions between the gastrointestinal drugs calcium carbonate, ranitidine, omeprazole, and Carafate, and those used to treat common elderly diseases, such as hypertension, diabetes, hyperlipidemia, arthritis, and psychiatric illnesses.

Hypertension Medications

Table 1 illustrates interactions between common antihypertensive medications metoprolol, lisinopril, hydrochlorothiazide, furosemide, spironolactone, nifedipine, isosorbide, hydralazine, and losartan, and drugs used in acid peptic disease, such as Tums, ranitidine, omeprazole, and Carafate. As per Epocrates and Lexi-Comp databases, patients taking hydrochlorothiazide and calcium carbonate are at risk of developing hypercalcemia and require close monitoring of serum calcium levels. Patients taking omeprazole who are also taking furosemide, hydrochlorothiazide, and/or spironolactone have an increased risk of developing hypomagnesemia.

Table 1

Interactions between common medications used for hypertension and acid peptic disease

Diabetes Medications

Table 2 illustrates interaction between the diabetes medications metformin, glyburide, rosiglitazone, glargine, intermediate-acting insulin, and pioglitazone, and drugs used in acid peptic disease. Patients using metformin and ranitidine are at risk of having increased metformin levels. As per Epocrates and Lexi-Comp databases, elevated levels of metformin may lead to severe lactic acidosis, especially in patients with underlying renal disease. In patients taking this combination of drugs, baseline renal function should be noted and monitored closely.

Table 2

Interactions between common medications used for diabetes and acid peptic disease

Hyperlipidemia Medications

As illustrated in Table 3, no significant interaction has been noted between drugs used in acid peptic disease and those used for hyperlipidemia (simvastatin, pravastatin, fenofibrate, niacin, and cholestyramine).

Table 3

Interactions between common medications used for hyperlipidemia and acid peptic disease

Arthritis/Pain Medications

As per Epocrates and Lexi-Comp databases, the only significant interaction described involving arthritis and pain medications is between enteric-coated naproxen and omeprazole. This combination can result in the premature dissolution of the enteric coating, causing increase gastrointestinal side effects associated with naproxen (Table 4).

Table 4

Interactions between common medications used for pain/arthritis and acid peptic disease

Psychotropic Medications

As per Epocrates and Lexi-Comp databases, the only interaction between the outlined psychotropic medications and antisecretory agents listed in Table 5 is between diazepam and omeprazole. As per Epocrates and Lexi-Comp databases, the concomitant use of a proton pump inhibitor can increase the drug levels of diazepam. Therefore, careful monitoring and dose reduction of the benzodiazepine may be warranted to avoid the risk of oversedation or psychomotor impairment.

Table 5

Interactions between common psychotropic medications and those used in acid peptic disease

Constipation

Constipation is a common problem in elderly persons, with prevalence ranging from 15% to 20% in the community-dwelling elderly population, and up to 50% in nursing home residents. In the elderly, constipation has a multifactorial cause. Often more than one mechanism is present in a single patient, such as comorbid illnesses or medication side effects. The authors analyzed interactions between drugs used to treat constipation (psyllium, docusate, magnesium hydroxide, lactulose, bisacodyl, lubiprostone, linaclotide) and...