Problematic polypharmacy and unintentional prescribing cascades: perspectives of key stakeholders

Dr Aisling A. Jennings is a GP in Cork, Ireland, and a Senior Lecturer in the Dept. of General Practice, School of Medicine in University College Cork. Contact her via email at Aisling [dot] jennings [at] ucc [dot] ie or find her on X (formerly Twitter) at @aislingjennings.

“So, he was on antihypertensives and then he was also on diuretics but then he was peeing too much, and he saw a urologist who put him on something for overactive bladder, to stop him peeing so much. And then he started getting hypotensive and then another specialist put him on something to bring his blood pressure back up. So, like he came in to me on something to bring his blood pressure down, something to bring his blood pressure up, something to make him pee and something to make him not pee.” (GP3)

Polypharmacy is common in older adults. This is, in part, because of increasing multimorbidity in an ageing population. Of course, polypharmacy can be a clinically appropriate response to multimorbidity. However, polypharmacy becomes problematic for an older adult when the medicines prescribed are not clinically indicated or when they cause more harm than benefit. Older adults are particularly vulnerable to the adverse consequences of problematic polypharmacy. These include increased risk of emergency hospitalisations, adverse drug reactions (ADRs) and unintentional prescribing cascades.

Unintentional prescribing cascades occur if a person develops an adverse reaction to a medication, but the ADR is misinterpreted as a new symptom, which results in a prescription for a new medication. For example, a patient who presents with ankle oedema due to an ADR to the calcium channel blocker prescribed for hypertension is then prescribed a diuretic, as the ankle oedema was misinterpreted as representing a symptom of heart failure. When this occurs, the patient continues to be exposed to the ADR from the culprit medication but is now also exposed to the additional risk from the newly prescribed medication.

When trying to identify prescribing cascades in older adults with multimorbidity there are typically several potential culprit medications and multiple underlying medical conditions. This makes the process of identifying a prescribing cascade very challenging. To develop effective interventions in this area we need to fully understand the issues that contribute to problematic polypharmacy and unintentional prescribing cascades from the perspective of the key people involved.

In our study, published in the June 2024 issue of Age and Ageing, we conducted a stakeholder analysis to explore perceptions of problematic polypharmacy with a focus on unintentional prescribing cascades. We conducted semi-structured qualitative interviews with 31 key stakeholders in the area of polypharmacy: six patients with polypharmacy, two carers, seven GPs, four hospital doctors, eight community pharmacists, two professional organisation representatives, and two policymakers.

We identified three main themes.

1) ADRs and unintentional prescribing cascades were seen as a necessary evil.

Although different healthcare professional groups had varying degrees of belief in the importance of medication adherence, all groups perceived ADRs and prescribing cascades to be unavoidable consequences of polypharmacy. Healthcare professionals were willing to tolerate ADRs and unintentional prescribing cascades, but they expressed concern that experiencing these would negatively impact the patient’s trust in medication and confidence in their doctor. However, patients viewed ADRs pragmatically as an unpredictable risk that did not impact on either their trust in medications or in their doctors. This high level of tolerance occurred in the context of patients’ and carers’ trust in their doctor’s prescribing.

2) Balancing the risk/benefit tipping point

Decisions to prescribe (or not to prescribe) medications to older adults with polypharmacy was described as a careful balancing act. Initiating a new medication or deprescribing an existing medication risked disrupting the ‘very unsteady equilibrium’ (GP7) and tipping the scale unfavourably into risk. The challenges of identifying a prescribing cascade within the “cocktail of medicines” prescribed to an older adult with polypharmacy were highlighted. At a certain level of polypharmacy, the risk that a new symptom is being caused by an existing medication becomes incalculable. A tipping point is reached where prescribing in the context of polypharmacy becomes so complex that effective risk assessment seemed unfeasible.

3) The minefield of medication reconciliation

Reconciliation of medications in an older adult post hospital discharge was perceived to be fraught with risk. It was frequently referred to by different stakeholder groups as a “minefield”. See Figure 1 for a graphical representation of what stakeholders perceived to be the barriers to effective and safe communication of medication changes post hospital discharge. Stakeholders felt that one professional group should provide prescribing stewardship and be responsible for untangling the web of prescribing. However, there was uncertainty as to who should take on this responsibility. Many participants felt a clinical pharmacist working in general practice could help provide this oversight.