ANTIMUSCARINIC DRUGS FOR OVERACTIVE BLADDER AND THEIR POTENTIAL EFFECTS ON COGNITIVE FUNCTION IN OLDER PATIENTS (2006)

To the Editor: I enjoyed reading the scholarly work of Kay et al. entitled, “Antimuscarinic drugs for overactive bladder and their potential effects on cognitive function in older patients.”1 I am writing to remind the reader of another potential adverse effect of antimuscarinic drugs in frail older people. Anticholinergic medications not only affect bladder motility, they also affect gastrointestinal motility. Anticholinergic drugs have been reported to be a risk factor for aspiration pneumonia, the most lethal infection in nursing home residents.2,3 It is likely that many of the neuropathologies that cause dementia and peripheral neuropathy also affect the enteric nervous system. Visceral enteric neuropathies are probably common in nursing home residents and are manifested by tertiary contractions of the esophagus and diabetic gastroparesis. A review of the labeling information provided in the 2006 Physician's Desk Reference for nongeneric antimuscarinic drugs used for overactive bladder indicates that these agents are contraindicated in the presence of gastric retention. In addition, the presence of decreased gastrointestinal motility is listed as a precaution. Clinicians seldom study or quantitate gastrointestinal motility. The labeling of oxybutynin specifically recommends cautious use in the presence of gastroesophageal reflux disease. The percentage of subjects who experienced dyspepsia is listed as being from 0.9% to 5.8% greater than placebo. Trospium is considered to be an “antispasmodic” and has been shown to delay gastric emptying and to increase reflux (i.e., the fractional time of esophageal pH <4) in healthy subjects.4 Regurgitated aspirated material (food, acid, or particulate material) may produce wheezing or “bronchitis,” or a chemical pneumonitis, and may produce pulmonary infection if the aspirated material is colonized with bacteria. Proton pump inhibitor-induced hypochlorhydria or gastric stasis facilitate gastric colonization.5 The use of gastric acid–suppressive drugs is a risk factor for community-acquired pneumonia.6 Macro-aspiration episodes caused by gastric regurgitation often have an acute onset and may be associated with postprandial or recumbent “emesis” or gastric material on the cheek, pillow, or clothing.7 I believe that these episodes are relatively common and that most physicians fail to appreciate this mechanism. Aspiration that occurs in the recumbent position produces infiltrates located in the mid-lung fields, including the posterior segment of the upper lobe and apical segments of the lower lobes. One study supports the possibility that many cases of aspiration “pneumonia” may be related to aspiration of food, acid, or particulate material without infection.8 Protected bronchoalveolar lavage specimens were obtained within 4 hours of any antibiotic administration from 95 intubated residents admitted directly from a nursing home to an intensive care unit with risk factors for pharyngeal aspiration or reflux. In 41 of 95, clinicians failed to isolate bacteria during bronchoalveolar lavage, suggesting the presence of nonbacterial “pneumonitis.” Reflux and regurgitation are also an acknowledged cause of asthmatic bronchitis and chronic cough.9 In one study, aspiration pneumonia accounted for more than one-third of deaths attributed to gastroesophageal reflux disease.10 It is unclear how often antimuscarinic drugs lead to pulmonary aspiration events, but in the frail elderly, I believe that this potentially lethal possibility deserves the same level of concern as that given to cognitive dysfunction. Financial Disclosure: None. Author Contributions: P. J. Drinka was responsible for all aspects of the manuscript. Sponsor's Role: None.