Hydralazine-Induced Diarrhea in a Geriatric Patient: A Case Report and a Review of the Literature on Deprescribing as a Diagnostic Strategy.

Older adults can be particularly susceptible to adverse drug reactions (ADRs) due to age-related physiological changes, decline in renal and hepatic function, and chronic comorbidities. Drug-induced diarrhea (DID) can often be hard to identify in the older adult population due to polypharmacy and the constant addition of new medications to treat the side effects of previous medications. The early identification of DID is important to prevent complications that can lead to prolonged hospitalization and increased mortality. Hydralazine, a vasodilator used for blood pressure management, can potentially cause gastrointestinal abnormalities such as nausea, vomiting, paralytic ileus, and constipation, but the frequency of these adverse effects is not specified. Here, we discuss a case of a 74-year-old hospitalized woman who developed diarrhea shortly after the initiation of hydralazine, which led to the development of an acute kidney injury and the need for prolonged hospitalization. The diarrhea worsened with hydralazine dose escalation and resolved within 24 hours of the discontinuation of hydralazine. Other medications that could potentially cause diarrhea, including antibiotics, intravenous magnesium, and HIV therapy, were ruled out by a thorough medication review. A score of 6 on the Naranjo algorithm indicates a probable cause relationship between the diarrhea and hydralazine. This case emphasizes the importance of thorough medication reviews to identify drugs that are not commonly associated with DID.