Prescription Trends and Contributing Factors of Medications Causing Xerostomia in Elderly Patients

Xerostomia is a syndrome characterized by subjective or objective findings of oral dryness. One quarter of the elderly population suffers from xerostomia owing to a decline in salivary secretion function with age and problems with oral closure. Additionally, many ethical drugs have xerostomia listed as an adverse drug reaction. Xerostomia reduces the self-cleansing action of the mouth and can cause problems in maintaining oral health. In this study, we created a list of drugs associated with xerostomia from these package inserts. Then, electronic medical record data from Keio University Hospital were analyzed to investigate prescribing trends among elderly patients and to identify patient characteristics associated with these drugs. Patients who received continuous prescriptions from April 2019 to March 2020 were included in this study based on age, prescribed drugs, and associated diseases. Among the 575 patients analyzed, 464 (80.7％) were prescribed at least one xerostomia-inducing medication. Compared with the early-stage elderly, a significantly higher proportion of late-stage elderly patients received these medications (P < 0.001) and had multiple prescriptions (P < 0.001). Logistic regression analysis examined the presence and multiple prescriptions of xerostomia-inducing drugs, showing significant associations with late-stage elderly patients and polypharmacy. The most common conditions among patients prescribed xerostomia-inducing drugs were endocrine, nutritional, metabolic, cardiovascular, and gastrointestinal diseases. Accordingly, vasodilators, peptic ulcer drugs, and hyperlipidemic drugs were frequently prescribed to these patients. The results suggest that the risk of xerostomia should be a point of consideration when prescribing multiple medicines to elderly patients.