A prescribing cascade refers to the sequence of events in which an adverse drug event is misinterpreted as a new medical condition, leading to the addition of another, potentially avoidable, medication1
For example, calcium channel blockers may cause ankle edema for which a diuretic may be prescribed. In a cohort study, this particular cascade occurred in 9.5% of older adults who were newly prescribed a calcium channel blocker (Appendix 1, available at www.cmaj.ca/lookup/doi/10.1503/cmaj.201564/tab-related-content).2
Serious adverse events can result in admission to hospital
In one case, a patient developed a cough after starting an angiotensin-converting-enzyme inhibitor. A cough syrup with guafenasin and codeine was prescribed, leading to lethargy.3 Levofloxacin was started for presumed pneumonia, which led to diarrhea, followed by delirium and admission to hospital.
Cascades contribute to inappropriate polypharmacy, particularly in older adults
Patients with chronic conditions and geriatric syndromes that require complex drug regimens are at increased risk for problematic and inappropriate polypharmacy.4
Cascades can be identified and inappropriate polypharmacy prevented1
Prescribers should ask themselves, “Is the patient reporting a symptom that could represent an adverse drug event?” and “Is a new drug being considered to address an adverse event that may relate to a previously prescribed drug therapy?” If the answer to either question is yes, prescribers should ask, “Could the initial drug be substituted for a safer alternative or could the dose be reduced, potentially eliminating the need for the subsequent drug therapy?” and “Does the patient need the initial drug therapy or could it be stopped?”
Consider deprescribing when a cascade is identified
Deprescribing is the process of tapering or stopping drugs that may not be indicated, according to patients’ priorities, to minimize polypharmacy and improve patient outcomes.5
Footnotes
CMAJ Podcasts: author interview at www.cmaj.ca/lookup/doi/10.1503/cmaj.201564/tab-related-content
Competing interests: None declared.
This article has been peer reviewed.
Funding: The iKascade project is funded by GENDER NET Plus (GNP-1782) in partnership with the Canadian Institutes of Health Research (Institute of Gender & Health and Institute of Aging), the Irish Research Council, Ministero della Salute (Italy) and the Ministry of Science, Technology and Space (Israel).
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