Polypharmacy and Deprescribing

Introduction

Polypharmacy - the concurrent use of multiple medicines by one person - is extremely common in older people, most of whom have at least one long-term condition and many of whom have several. It is not inherently a problem: many older people are appropriately prescribed five, ten or more regular medicines, each addressing a genuine indication with net benefit. The clinical skill is distinguishing appropriate from problematic polypharmacy, and having a safe, structured process for reducing the latter.¹

This matters because the risk of adverse drug events, drug-drug interactions and drug-disease interactions rises steeply, not linearly, as the number of concurrent medicines increases - and because polypharmacy is one of the most common, and most fixable, contributors to falls, delirium, hospital admission and reduced quality of life in older people.

Appropriate versus problematic polypharmacy

Why older people are at higher risk

• Altered pharmacokinetics: reduced renal and hepatic clearance, altered volume of distribution (reduced lean mass, increased fat), meaning standard adult doses can accumulate to toxic levels
• Altered pharmacodynamics: increased sensitivity to certain drug classes - for example, greater sedative and hypotensive effect at a given dose, and increased susceptibility to anticholinergic and central nervous system side effects
• Reduced physiological reserve (frailty): less capacity to compensate for an adverse effect, meaning a modest drug-induced fall in blood pressure or level of consciousness has a disproportionately larger clinical impact - see ²
• Guideline stacking: applying every relevant single-disease guideline in full generates additive medicine burden - see ³ for the multimorbidity perspective
• Reduced capacity to manage a complex regimen, particularly with coexisting cognitive impairment

The prescribing cascade

A prescribing cascade occurs when a new drug is started to treat what is actually a side effect of an existing drug, rather than the side effect being recognised and the causative drug reviewed. This is a common, avoidable driver of polypharmacy that is worth naming explicitly in any medication review.

STOPP/START criteria

STOPP (Screening Tool of Older Persons' Prescriptions) and START (Screening Tool to Alert to Right Treatment) are complementary, validated criteria widely used in UK practice to structure medication review in people aged 65 and over.⁴

Using both together avoids the common error of a review that only removes medicines and never considers what evidence-based treatment might genuinely be missing.

Anticholinergic and sedative burden

Many individually 'acceptable' drugs have anticholinergic or sedative properties that are additive when combined - the cumulative anticholinergic burden matters more than any single drug in isolation. Common contributors include tricyclic antidepressants, some antihistamines (particularly older, sedating ones), bladder antimuscarinics (oxybutynin, tolterodine), some antipsychotics, and some Parkinson's drugs.

A structured approach to deprescribing

Deprescribing is the planned, supervised process of stopping or reducing a medicine when its harms or burden now outweigh its benefit, or its original indication no longer applies - a deliberate clinical decision, not a passive drift or crisis reaction.

1. Compile a complete, accurate medication list, including over-the-counter and herbal remedies, and confirm what the patient is actually taking versus what is prescribed
2. Identify each drug's indication and whether it is still valid
3. Assess overall benefit versus harm/burden for this individual, given their frailty, goals and life expectancy
4. Prioritise which drug to address first - usually starting with the highest-risk, lowest-benefit drug (e.g. one with a known prescribing cascade, or one no longer clearly indicated)
5. Plan the withdrawal, including tapering where needed and a monitoring plan for withdrawal or rebound effects
6. Involve the patient in the decision, explaining the rationale clearly - deprescribing can otherwise feel to a patient like their care is being reduced or their doctor is 'giving up'
7. Review and monitor after each change before making the next one, rather than stopping several drugs simultaneously

Drug classes most often targeted for deprescribing

Certain classes recur repeatedly in deprescribing work because they combine high prevalence, meaningful harm in older people, and frequently absent or expired indications.

Structured medication review in practice

In UK primary care, structured medication reviews are increasingly delivered by clinical pharmacists integrated into general practice teams, working alongside GPs, and are a formal component of chronic disease review (see ⁵) and of care for patients identified as frail or on the multimorbidity pathway. Triggers for a structured medication review include: 10 or more regular medicines, a recent hospital admission, a fall, new confusion, a change in renal function, or entry to a care home.

Discussing deprescribing with patients

Deprescribing conversations fail more often for communication reasons than clinical ones. Patients who have been told for years that a medicine is important may hear a proposal to stop it as rationing, as a sign that treatment is being withdrawn because they are near the end of life, or as an implication that they were wrong to take it. Framing matters as much as the pharmacology.

• Open by asking their view: what they think each medicine does, which ones they feel help, and whether any are a nuisance to take - most patients readily identify candidates themselves
• Explain the rationale positively: 'this one was helping when your blood pressure was higher, but now it may be causing the dizziness' rather than 'you don't need this any more'
• Name the trade-off honestly, including any small increase in risk, rather than presenting the decision as risk-free
• Emphasise reversibility: framing it as a monitored trial that can be reversed if symptoms return substantially reduces anxiety and increases agreement
• Agree a specific review point and tell the patient what to look out for in the meantime
• Document the reasoning, so a future clinician does not simply restart the drug without knowing why it was stopped

Common pitfalls

• Reviewing medication only reactively (after a crisis) rather than proactively at routine intervals
• Stopping multiple drugs simultaneously, making it hard to identify the cause if something goes wrong
• Failing to taper drugs that require gradual withdrawal
• Focusing only on stopping drugs (STOPP) while missing evidence-based treatment that should be started (START)
• Not involving the patient in the decision, risking loss of trust or non-adherence to the revised plan
• Assuming problematic polypharmacy only applies to a high absolute number of drugs, missing genuinely harmful combinations at a lower count

Prognosis and impact

Structured deprescribing, done well, reduces adverse drug events, falls, and sometimes hospital admission, while improving quality of life through reduced treatment burden - without evidence of net harm from appropriately selected medication withdrawal. The evidence base for individual deprescribing decisions varies by drug class, but the overall principle - regular, structured, patient-involved review rather than indefinite, unreviewed continuation - is consistently supported and applies across virtually every older patient with multiple medicines.