Pharmacology in Elderly Patients

Age-Related Pharmacokinetic Changes

Ageing does not cause uniform drug changes — each phase is affected differently. Nurses must understand these changes to anticipate toxicity, reduced efficacy, and altered dosing requirements.

Absorption

Physiological Changes

Gastric pH increases (reduced acid secretion)
GI motility slows — delayed gastric emptying
Reduced splanchnic blood flow
Reduced active transport mechanisms

Clinical Consequences

Delayed absorption — peak levels reached later
Reduced first-pass effect in gut wall — higher bioavailability of some drugs (e.g. morphine)
Acid-dependent drugs (ketoconazole, iron) may absorb poorly
Enteric-coated tablets may dissolve earlier than intended

Distribution

Reduced Body Water
Higher plasma concentration of water-soluble drugs

Affected Drugs

Digoxin Lithium Aminoglycosides Ethanol

Give lower loading doses. Monitor levels closely.

Increased Body Fat
Longer half-life of fat-soluble drugs — prolonged effect and accumulation

Affected Drugs

Benzodiazepines Diazepam Amiodarone Verapamil

Extended sedation, slow offset. Accumulation with repeated doses.

Reduced Serum Albumin
Increased free fraction of protein-bound drugs — more active drug, greater effect and toxicity

Affected Drugs

Warfarin Phenytoin Diazepam NSAIDs

Monitor total drug levels carefully — free fraction may be elevated even when total level appears normal.

Metabolism (Hepatic)

Changes

Reduced hepatic blood flow (up to 40% decrease)
Reduced CYP450 enzyme activity (Phase I reactions predominantly)
Reduced liver mass
Phase II (conjugation) relatively preserved

Clinical Impact

Reduced first-pass metabolism — higher bioavailability of orally administered drugs
Slower hepatic clearance — drugs accumulate with repeated dosing
High-extraction drugs most affected: morphine, propranolol, lidocaine, nitrates
No reliable clinical test for hepatic drug-metabolising capacity

Prefer drugs cleared by Phase II conjugation (e.g. lorazepam, oxazepam) over Phase I-dependent drugs (e.g. diazepam) in elderly patients.

Excretion (Renal)

Key Facts

GFR declines approximately 1 ml/min/year after age 40
An 80-year-old may have GFR of ~40 ml/min even with "normal" serum creatinine
Creatinine is misleading in sarcopenic elderly — low muscle mass = low creatinine production despite impaired renal function
Use CKD-EPI or Cockcroft-Gault formula. Consider cystatin C if available.

Drugs Requiring Renal Dose Adjustment

Drug	Risk
Digoxin	Toxicity — bradycardia, arrhythmia
Metformin	Lactic acidosis (stop if eGFR <30)
NSAIDs	Acute kidney injury
Aminoglycosides	Nephrotoxicity, ototoxicity
NOACs (dabigatran)	Bleeding (renally cleared)
Gabapentin/pregabalin	Excessive sedation
Lithium	Toxicity — narrow therapeutic index

Pharmacodynamics — Altered Drug Response

Increased CNS Sensitivity
Enhanced response to sedatives, opioids, antipsychotics, benzodiazepines — lower doses produce greater effect and side effects

Orthostatic Hypotension
Increased response to antihypertensives, diuretics, alpha-blockers, nitrates — greater postural BP drop. Decreased baroreceptor sensitivity worsens reflex compensation.

Cardiac Sensitivity
Reduced beta-receptor responsiveness — diminished heart rate response to beta-blockers and beta-agonists. QT prolongation risk increased.

START LOW, GO SLOW — The cardinal principle of geriatric prescribing. Initiate at 25-50% of standard adult dose and titrate based on clinical response and tolerability.

High-Risk Drugs in Elderly Patients

Beers Criteria — American Geriatrics Society (AGS)

The Beers Criteria identifies medications that are potentially inappropriate in older adults (generally age ≥65). Updated regularly by the AGS. Essential knowledge for DHA/DOH/SCFHS exams.

Drug/Class	Why Avoid	Clinical Risk
Benzodiazepines (all)	Accumulation, increased sensitivity	Falls, fractures, cognitive impairment, dependence
Z-drugs (zopiclone, zolpidem)	Similar to benzodiazepines	Falls, confusion, next-day sedation
Anticholinergics	CNS crosses BBB; peripheral effects	Delirium, constipation, urinary retention, dry mouth
PPIs (long-term >8 weeks)	Overuse, C. diff risk, malabsorption	Clostridium difficile, hip fractures, B12/Mg deficiency
NSAIDs	Renal impairment, GI bleeding	AKI, peptic ulcer, fluid retention, hypertension
Antipsychotics (in dementia)	Increased stroke/mortality risk	Stroke, falls, parkinsonism, aspiration pneumonia
Tricyclic antidepressants	Anticholinergic, cardiotoxic	Delirium, arrhythmia, orthostatic hypotension, falls
Digoxin >0.125 mg/day	Reduced renal clearance in elderly	Toxicity: bradycardia, nausea, visual disturbances, arrhythmias
Sliding scale insulin	Reactive dosing without fixed base	Hypoglycaemia, inconsistent control
Skeletal muscle relaxants	Excessive CNS effects	Sedation, confusion, falls — minimal evidence of benefit in elderly

Anticholinergic Cognitive Burden (ACB) Scale

The ACB score quantifies the cumulative anticholinergic burden across all prescribed medications. A total score of 3 or more is clinically significant.

ACB Score	Meaning	Clinical Risk
0	No anticholinergic activity	No increased risk
1	Mild anticholinergic activity	Low individual risk but contributes to total burden
2	Moderate anticholinergic activity	Monitor for effects
3	Severe anticholinergic activity	High risk — use only if essential

Clinical Risks when ACB Total ≥3

Falls Cognitive Impairment Delirium Constipation Urinary Retention Dry Mouth Blurred Vision Tachycardia

Common Medications with ACB Scores

Medication	ACB Score	Category
Amitriptyline, Imipramine (TCAs)	3	Antidepressant
Oxybutynin	3	Antimuscarinic (bladder)
Chlorphenamine (Piriton)	3	Antihistamine
Paroxetine	2	SSRI — highest anticholinergic of class
Olanzapine, Clozapine	2–3	Antipsychotic
Codeine	1	Opioid analgesic
Furosemide	1	Loop diuretic
Metoclopramide	1	Antiemetic
Digoxin	1	Cardiac glycoside
Haloperidol	1	Antipsychotic

START Criteria — Drugs to Consider Prescribing

START (Screening Tool to Alert to Right Treatment) identifies drugs that are commonly omitted in elderly patients who would benefit. Polypharmacy review should include adding missing evidence-based therapies.

Cardiovascular

Antiplatelet therapy in documented IHD/stroke
ACE inhibitor/ARB in systolic heart failure or diabetic nephropathy
Anticoagulation for AF with CHA2DS2-VASc ≥2
Statin in established cardiovascular disease (if not frail/end-stage)

Other Systems

Bisphosphonate + Vitamin D + Calcium in osteoporosis
PPI with NSAIDs or anticoagulants at high GI risk
Laxatives in patients on opioids
Influenza and pneumococcal vaccination
B12 supplementation in documented deficiency
Adequate analgesia in documented pain (avoid undertreating)

CNS Drugs in Elderly Patients

Benzodiazepines

Benzodiazepines are on the Beers Criteria — avoid in elderly unless absolutely indicated. If already prescribed, a structured tapering plan is required.

Risks in Elderly

Accumulation — prolonged half-life due to increased body fat and reduced hepatic clearance
Daytime sedation and cognitive impairment
Falls and hip fractures
Paradoxical agitation (especially in dementia)
Dependence and withdrawal syndrome
Respiratory depression, especially with opioids

Drug Selection Considerations

Drug	Half-life	Notes
Diazepam	Very long (20–100h + active metabolites)	Avoid in elderly
Clonazepam	Long (20–60h)	Avoid
Lorazepam	Short (10–20h)	Prefer if must use — Phase II, no active metabolites
Oxazepam	Short (5–15h)	Prefer if must use — same reason

Tapering Protocol

Reduce by 10–25% of current dose every 2 weeks. Slower taper (5–10%) for long-term users. Warn patient about rebound insomnia — normal, temporary. Avoid abrupt cessation — risk of withdrawal seizures.

Antidepressants in Elderly

Drug/Class	Recommendation	Key Notes
Sertraline (SSRI)	Preferred first-line	Safest SSRI in elderly. Check Na+ — hyponatraemia risk (SIADH). Start 25–50mg.
Citalopram/Escitalopram	Acceptable	QTc prolongation risk — max 20mg citalopram in elderly. Monitor ECG.
Mirtazapine	Useful in select patients	Appetite stimulant, sedating — beneficial in underweight/insomnia. Watch weight gain, sedation, falls.
Paroxetine (SSRI)	Avoid	Highest anticholinergic burden of SSRIs. Significant drug interactions. Abrupt discontinuation syndrome.
Venlafaxine (SNRI)	Caution	Hypertension, QTc prolongation, discontinuation symptoms. Use lower doses.
TCAs (amitriptyline, etc.)	Avoid in elderly	Anticholinergic, cardiotoxic (arrhythmias), orthostatic hypotension, falls, delirium. Beers Criteria.

Hyponatraemia Monitoring: All SSRIs/SNRIs can cause SIADH. Check serum Na+ at baseline, 2 weeks, and 6 weeks after starting. Elderly at highest risk. Na+ <130 mmol/L requires urgent review.

Antipsychotics in Dementia (BPSD)

Black Box Warning: Antipsychotics in elderly patients with dementia are associated with a 1.6–1.7x increased risk of death and increased risk of stroke. Use only when non-pharmacological strategies have failed and the patient has severe BPSD causing risk to themselves or others.

Non-pharmacological First

Identify and address triggers (pain, constipation, infection, dehydration)
Consistent routine and familiar environment
Therapeutic activities and sensory stimulation
Adequate sleep hygiene
Family involvement and carer training

When Medication Is Necessary

Drug	Notes
Haloperidol	Least anticholinergic (ACB 1). High EPS risk. Use lowest dose. IM available for acute agitation.
Quetiapine	Commonly used — some evidence for BPSD. Sedating, orthostatic hypotension, metabolic effects. Weaker evidence base.
Risperidone	Only antipsychotic with a UK/international license for short-term BPSD. High EPS risk.
Olanzapine	ACB 2–3. High anticholinergic. Avoid in dementia.

If starting antipsychotics for BPSD: document indication, review date (6–12 weeks), and that risks were discussed. Aim to discontinue as soon as possible. Review at every medication reconciliation.

Cardiovascular & Metabolic Drugs in Elderly

Antihypertensives

J-Shaped Curve Risk: In frail patients over 75, BP <130/70 mmHg may increase harm — including falls, cerebral hypoperfusion, and increased mortality. SPRINT trial benefits should not be extrapolated to frail elderly without careful individual assessment.

Orthostatic Hypotension — Monitoring

Measure BP lying and standing (after 1 and 3 minutes)
Significant if systolic drops ≥20 mmHg or diastolic ≥10 mmHg
Check after each dose increase
Assess for symptoms: dizziness, near-syncope, falls
Time of day matters — worst in morning

Diuretics — Monitoring Priorities

Loop diuretics (furosemide): monitor Na+, K+, urea, creatinine, weight, fluid balance
Hyponatraemia, hypokalaemia, dehydration, pre-renal AKI
Thiazides: electrolyte monitoring; avoid in eGFR <30 (reduced efficacy)
Avoid evening doses — nocturia causes night-time mobilisation and falls risk
Spironolactone: hyperkalaemia risk — especially with ACE inhibitors/ARBs

Anticoagulation in Elderly

NOACs vs Warfarin

NOACs preferred over warfarin in most elderly AF patients
No routine INR monitoring required (but compliance check still needed)
Lower intracranial haemorrhage risk than warfarin
Falls: a single fall is not an absolute contraindication — estimated 300 falls required to negate the stroke prevention benefit
Warfarin has more drug and food interactions — difficult to manage in polypharmacy

NOAC Selection by Renal Function

NOAC	Renal Clearance	Preference
Apixaban	~27%	Preferred in CKD/elderly
Rivaroxaban	~36%	Acceptable
Edoxaban	~50%	Caution in CKD
Dabigatran	~80%	Avoid if eGFR <50

Monitoring Essentials

Monitor renal function (eGFR) at least annually — more frequently if declining
eGFR decline requires dose adjustment or switch
Review HAS-BLED score for bleeding risk
Check all concurrent medications for interactions (especially amiodarone, verapamil, NSAIDs)

Signs of NOAC overdose/bleeding: Haematuria, prolonged bleeding from cuts, haemoptysis, GI bleeding, sudden headache (ICH). No routine antidote except for dabigatran (idarucizumab) and andexanet alfa for factor Xa inhibitors.

Diabetes Management in Elderly

Less Stringent HbA1c Targets: In patients ≥75 years or frail/functionally dependent, HbA1c target 7.5–8.5% (58–69 mmol/mol) is appropriate. Hypoglycaemia and functional decline are more harmful than modest microvascular risk reduction.

Hypoglycaemia — Particular Risks in Elderly

Blunted adrenergic symptoms (less warning) — may present as confusion, falls, or silent event
Severe hypoglycaemia associated with dementia, arrhythmia, and death
Sulfonylureas (glibenclamide especially) — Avoid in elderly
Glipizide (short-acting): Acceptable if sulfonylurea required
Insulin: use simple regimens — avoid complex basal-bolus in cognitively impaired
SGLT2 inhibitors: risk of genital infections, dehydration, DKA — review in frail/elderly

Preferred Agents in Elderly

Drug	Notes
Metformin	First-line if tolerated. Stop if eGFR <30. Hold peri-contrast/surgery.
DPP-4 inhibitors (gliptins)	Weight-neutral, low hypoglycaemia risk. Dose adjust in CKD.
GLP-1 agonists	Weight loss — careful in underweight elderly. GI side effects may worsen sarcopenia.
Insulin (basal)	Once-daily long-acting preferred for simplicity and compliance.

Statins — Deprescribing Considerations

When to Consider Stopping

Limited life expectancy (<1–2 years)
Advanced frailty or dementia
No established cardiovascular disease (primary prevention only)
Patient preference after informed discussion
Significant side effects: myopathy, rhabdomyolysis risk
High pill burden causing adherence problems

When to Continue

Established CVD with reasonable life expectancy
Patient tolerates well and wishes to continue
Recent ACS — at least 1–2 years high-intensity statin recommended
No significant drug interactions

Myopathy risk: increased with concurrent ciclosporin, amiodarone, verapamil, fibrates. Simvastatin 80mg avoided due to high myopathy risk.

Prescribing Frameworks & Practical Nursing

Medication Administration Adaptations

Swallowing Difficulties (Dysphagia)

Liquid formulations — check alcohol content (relevant in Muslim patients in GCC)
Dispersible / orodispersible tablets — dissolve in water or on tongue
Crushing tablets — check with pharmacist first. Never crush: modified-release, enteric-coated, sublingual, cytotoxic drugs
Transdermal patches — fentanyl, buprenorphine, rivastigmine, estradiol, hyoscine
Subcutaneous route — for end-of-life care or when oral route unavailable

JustInCase Subcutaneous Kit (palliative/end-of-life): morphine (pain/breathlessness), midazolam (agitation/seizures), haloperidol/levomepromazine (nausea/agitation), hyoscine butylbromide (secretions)

Administration Timing Optimisation

Diuretics: morning dose preferred — avoid afternoon/evening to prevent nocturia and night-time falls
Bisphosphonates: morning, fasting, upright for 30 minutes, with full glass of water
Antihypertensives: evening dosing may reduce morning surge — individual assessment
Levodopa: consistent timing, away from high-protein meals
Digoxin: same time daily, check heart rate before administration (<60 — hold and report)
Warfarin: consistent evening time, monitor for missed doses

Pill Burden Reduction Strategies

Use once-daily formulations (modified-release) where available
Use combination preparations (e.g. amlodipine/valsartan, metformin/sitagliptin)
Regularly review the indication for each medicine — discontinue if no longer indicated
Structured medication reviews at care transitions (hospital discharge, new care home placement)
Use STOPP/START or Beers Criteria at each review

Medication adherence aids: blister packs (Dosette boxes), monitored dosage systems
Simplify regimen frequency: twice-daily where once-daily not possible
Engage pharmacist in polypharmacy reviews — clinical pharmacist-led medication reconciliation
Patient and carer education — understand purpose of each medicine
Deprescribing conversations — framed as intentional clinical decision, not treatment failure

Adverse Drug Reaction (ADR) Identification — ALARM Acronym

Letter	Stands For	Example
A	Adverse Drug Reaction	New symptom after starting/changing medication — rash after amoxicillin, confusion after opioid
L	Late Administration / Omission	Missed dose causing rebound — BP surge after missed antihypertensive, seizure after missed anticonvulsant
A	Altered Drug Absorption	Enteral feed reducing levothyroxine absorption; antacids reducing quinolone absorption
R	Renal/Hepatic Impairment	Metformin lactic acidosis in AKI; opioid accumulation in renal failure
M	Medication Interaction	Warfarin + amiodarone (INR rise); SSRIs + tramadol (serotonin syndrome)

BNF Monitoring Requirements — Key Drugs in Elderly

Drug	Monitoring	Frequency
Digoxin	Digoxin level, K+, renal function, HR before each dose	Every 6 months (more if renal decline)
Lithium	Lithium level, renal function, TFTs	Every 3–6 months (narrow therapeutic index)
Warfarin	INR	Weekly initially, then monthly when stable
Methotrexate	FBC, LFTs, renal function	Every 1–3 months
ACE inhibitors/ARBs	Renal function, K+, BP	1–2 weeks after initiation; 6 monthly
SSRIs	Serum Na+, weight, BP	2 weeks, 6 weeks, then 6 monthly
Antipsychotics	Weight, fasting glucose, lipids, BP, ECG (QTc), EPS	Baseline, 3 months, then annually
Amiodarone	TFTs, LFTs, CXR, pulmonary function	Every 6 months
NOACs	eGFR, FBC, LFTs	Annually (more frequently if eGFR declining)

Teaching Carers & Families

Core Education Points

Purpose of each medication — what it is treating
Signs of common side effects to watch for and report
What to do if a dose is missed (never double dose)
Storage requirements (some medications need refrigeration)
How to use devices: inhalers, insulin pens, eye drops

Safety Reminders

Never crush controlled release tablets
Never share medications between patients
Alcohol interactions — especially with sedatives, warfarin, metronidazole
Falls risk with new medications — supervise mobility initially
Herbal medicine interactions — always disclose to healthcare team
Document all medication-related education in nursing notes

GCC Clinical Context & Exam Preparation

GCC-Specific Considerations

Ageing Demographics
Gulf nationals are living longer with significant disease burden. Large population of elderly expatriate workers remaining in GCC countries. Polypharmacy extremely common — patients with hypertension, diabetes, dyslipidaemia, IHD, and CKD concurrently.

Traditional Medicine Interactions

Remedy	Known Interaction
Black Seed (Nigella sativa / Habbatus sauda)	Potentiates warfarin, may lower BP — hypotension risk with antihypertensives
Fenugreek (Methi / Hilba)	Hypoglycaemic effect — may potentiate insulin/oral hypoglycaemics
Garat / Qarat	Variable composition — may affect drug absorption
Olive oil / Sidr honey	Generally low interaction risk but high intake may affect glucose control

Cultural and Systemic Factors

Cultural stoicism: Elderly patients often under-report side effects or pain — active assessment required
Family-administered medications: High risk of dosing errors in home setting — carer education essential
Private healthcare fragmentation: Each specialist adds medications without reviewing the whole prescription — polypharmacy review crucial at every admission
Ramadan: Fasting affects dosing schedule — discuss medication timing adjustments before Ramadan for elderly on multiple chronic disease medications

Ramadan Medication Adjustments

Insulin: adjust to avoid hypoglycaemia during fast — involve diabetes team
Diuretics: timing shift to reduce dehydration risk
Antihypertensives: may need adjustment to iftar/suhoor timing
Patients with unstable conditions may be exempt from fasting — clinical guidance required

DHA / DOH / SCFHS Exam Preparation

Key examination topics in geriatric pharmacology for DHA (Dubai Health Authority), DOH (Department of Health Abu Dhabi), and SCFHS (Saudi Commission for Health Specialties) nursing licensing examinations.

High-Yield Exam Topics

Beers Criteria — name specific drugs to avoid and why
Anticholinergic burden — ACB scores, clinical risks, ALARM mnemonics
Age-related pharmacokinetic changes — all four phases with clinical examples
Digoxin toxicity — signs, causes in elderly, monitoring
Falls assessment — drugs contributing to falls, Beers falls-risk drugs
Hypoglycaemia in elderly — presentation differences, causative agents

Common Exam Questions

Why is serum creatinine unreliable in elderly for assessing renal function?
What is the "start low, go slow" principle?
Which benzodiazepine is preferred in elderly and why?
What are the signs of digoxin toxicity?
Name 5 medications on the Beers Criteria
What is the HbA1c target for frail elderly with diabetes?
Why is paroxetine avoided in elderly?
What is the ACB score and what score indicates significant risk?

Quick Fact Cards

GFR decline rate

After age 40

1 ml/min/year

ACB Significant Risk

Total score

≥3

HbA1c target (frail ≥75y)

Elderly diabetes

7.5–8.5%

Digoxin max dose elderly

Beers Criteria

0.125 mg

Benzo taper rate

Per 2 weeks

10–25%

Na+ threshold (SSRI)

Urgent review

<130

Anticholinergic Burden (ACB) Calculator

Select all medications the patient is currently prescribed. The calculator will sum ACB scores and provide clinical interpretation.

Total ACB Score

Clinical Risks at This Score

Medicines to Consider Deprescribing (by ACB)

Alternative Recommendations