A prescribing cascade begins when a drug is prescribed, an adverse drug event occurs that is misinterpreted as a new medical condition, and a subsequent drug is prescribed to treat this drug-induced adverse event. This concept can be expanded to link prescription drug therapy to development of new medical conditions that are managed with OTC therapies, supplements, or medical devices:
These cascades often involve whole drug classes, encompassing a multitude of agents:
Prescribing cascades most commonly occur when multiple drug therapies are used on a chronic basis, particularly in older patients. Most concerning is when a new symptom identified in an older person is falsely attributed to a new medical condition instead of a drug-related adverse event, and then results in the initiation of a new, unnecessary drug therapy.
EMRs could alert prescribers to potential prescribing cascades at the time of prescribing decisions, but at present tend to focus more on potential drug-drug interactions. As such, providers should be vigilant in identifying and interrupting prescribing cascades by routinely reflecting on 3 specific questions:
- Is a new drug being prescribed to address an adverse event from a previously prescribed drug therapy? Before starting a drug therapy to treat a new medical condition, consider whether this condition could be a drug-related adverse event.
- Is the initial drug therapy that led to the prescribing cascade really needed? (i.e., was the initial drug therapy absolutely necessary, could the initial drug be substituted for a safer alternative, or could the dose be reduced and therefore reduce the need for subsequent drug therapy?)
- What are the harms and benefits of continuing the drug therapy that led to the prescribing cascade? Consider the risks and benefits with the patient via the shared decision-making process.