What precautions should be taken when prescribing medications to geriatric patients with a history of cardiovascular disease or dementia?

Prescribing Medications to Geriatric Patients with Cardiovascular Disease or Dementia

Start all cardiovascular and psychoactive medications at low doses (typically 50% of standard adult doses) and titrate slowly over 1-2 week intervals, monitoring closely for adverse drug reactions, drug-drug interactions, and functional decline at each visit. 1, 2

Core Prescribing Principles

Initial Assessment Requirements

• Obtain baseline cardiovascular screening including blood pressure (both sitting and standing), heart rate, ECG, and renal function before initiating any new medication 1, 2
• Check orthostatic vital signs at every visit as postural hypotension is a major cause of falls and injury in this population 1
• Review all current medications for potential drug-drug and drug-disease interactions before adding any new agent, as more than 80% of serious adverse drug reactions are dose-dependent and potentially avoidable 2
• Assess life expectancy and goals of care to determine whether preventive medications that take years to show benefit are appropriate 1

Critical Safety Rule

Any new symptom in older people should be considered a possible adverse drug reaction until proven otherwise to avoid prescribing cascades where side effects are mistaken for new conditions requiring additional medications 1, 2

Cardiovascular Disease-Specific Precautions

ACE Inhibitors/ARBs

• Start at low doses as high starting doses can precipitate hypotension or acute renal insufficiency 1
• Monitor renal function and potassium levels due to increased risk of hyperkalemia, acute kidney injury, falls, dizziness, and fatigue 1
• Consider these potentially inappropriate medications in people ≥75 years depending on individual risk-benefit assessment 1

Anticoagulants (DOACs, Warfarin)

• DOACs require dose adjustment or avoidance if creatinine clearance <15-30 mL/min/1.73 m² (dabigatran <30, others <15) 1
• Monitor renal and hepatic function periodically as renal impairment increases bleeding risk 1
• Use dabigatran and rivaroxaban with caution in patients ≥75 years with atrial fibrillation or VTE due to increased gastrointestinal bleeding risk compared to warfarin 1
• Warfarin requires dose reduction in elderly with periodic INR monitoring; consider it potentially inappropriate for uncomplicated DVT >6 months or PE >12 months in people ≥75 years 1
• Avoid combining with antiplatelets, NSAIDs, SNRIs, or SSRIs due to additive bleeding risk 1

Antiplatelets

• Avoid prasugrel in patients with history of intracranial bleeding 1
• Consider proton pump inhibitor co-prescription in patients at high gastrointestinal bleeding risk 1
• Note that long-term antiplatelet use (any duration) is associated with higher dementia risk (OR 1.13-1.25), which must be weighed against cardiovascular benefits 3

Antiarrhythmics

• Amiodarone should not be first-line for atrial fibrillation unless structural heart disease is present; maximum maintenance dose is 200 mg/day 1
• Monitor ECG, serum potassium, and magnesium with all antiarrhythmic drugs 1
• Avoid in patients with QT-prolonging drugs due to proarrhythmia risk 1
• Be alert for cognitive impairment with amiodarone, digoxin, lidocaine, and metoprolol 1

Alpha-Adrenergic Blockers

• Not recommended for hypertension treatment as alternative agents have better risk/benefit ratios 1
• Monitor for postural hypotension, dizziness, and somnolence, especially when combined with diuretics or vasodilators 1

Dementia-Specific Medication Considerations

Cardiovascular Drugs in Dementia Patients

• Long-term use (≥5 years) of antihypertensives, diuretics, lipid-lowering drugs, and oral anticoagulants is associated with lower dementia risk (OR 0.75-0.91), supporting continuation when appropriate 3
• Combination therapy with antihypertensives plus diuretics, lipid-lowering drugs, and oral anticoagulants for ≥5 years shows even greater benefit (OR 0.66-0.84) 3
• However, in patients with advanced dementia and limited life expectancy, deprescribing should be part of usual care as preventive medications may cause more harm than benefit 4

Avoid Medications with Anticholinergic Effects

• Avoid class IA antiarrhythmics due to anticholinergic effects causing dry mouth, constipation, and urinary retention 1
• Avoid tricyclic antidepressants as first-line treatment due to anticholinergic effects that worsen cognition 5
• Avoid cyclobenzaprine (Flexeril) due to anticholinergic effects and sedation increasing fall risk 6

CNS-Active Medications

• Older adults show increased sensitivity to drugs acting on the central nervous system, and some cardiovascular drugs can increase neurocognitive impairment 2
• Avoid benzodiazepines (e.g., alprazolam/Xanax) due to increased sensitivity, fall risk, and cognitive impairment in elderly patients 6
• Avoid combining hydrocodone with benzodiazepines due to severe respiratory depression and death risk 6

Memantine Dosing in Dementia

• Start at 5 mg once daily and increase in 5 mg increments weekly to target dose of 20 mg/day (10 mg twice daily) 7
• Reduce target dose to 5 mg twice daily in severe renal impairment (creatinine clearance 5-29 mL/min) 7
• Use with caution in severe hepatic impairment 7

Depression Treatment in Dementia

First-Line Approach

• Implement non-pharmacological interventions first: physical exercise programs, psychoeducational interventions, cognitive stimulation, social engagement programs, and caregiver support 5, 8
• For moderate to severe depression, add an SSRI (preferably citalopram, escitalopram, or sertraline) due to favorable side effect profiles 5
• Avoid SSRIs with anticholinergic properties or long half-lives (such as fluoxetine) 5
• Start at low doses and titrate slowly to minimize side effects 5
• Evaluate treatment response after 3-4 weeks using quantitative measures 5
• Continue successful antidepressant treatment for at least 6 months after significant improvement 5

Critical Safety Warning

Never use antipsychotics for depression in dementia due to increased mortality risk 5

Monitoring and Deprescribing Strategy

Regular Monitoring Requirements

• Check standing and recumbent blood pressure at every visit 1
• Monitor renal function periodically, especially with ACE inhibitors/ARBs, diuretics, and DOACs 1
• Assess for fall risk and implement prevention strategies 6
• Review medication adherence as 30-75% of older people do not take medications as prescribed 1

When to Deprescribe

• In patients with life expectancy shorter than the time to benefit of preventive medications (e.g., statins take years to show benefit but cause myalgia early) 1
• In advanced dementia where goals of care are palliative and focus is on preserving functional independence and quality of life 1
• When adverse drug reactions occur, switch or withdraw the offending medication 4
• When multiple medications have overlapping side effect profiles creating additive risks for sedation, dizziness, and cognitive impairment 6

Deprescribing Caution

Discontinuation of beta-blockers, clonidine, digoxin, antiplatelets, and statins can be associated with adverse withdrawal effects, requiring careful planning 1

Drug-Drug Interaction Pitfalls

High-Risk Combinations to Avoid

• Anticoagulants + antiplatelets + NSAIDs + SNRIs/SSRIs: Multiplicative bleeding risk 1
• Multiple CNS depressants (opioids + benzodiazepines + muscle relaxants): Respiratory depression, falls, cognitive impairment 6
• NSAIDs in patients with history of myocardial infarction: Increased risk of recurrent cardiovascular events and blocks aspirin's cardioprotective effects 6
• Stimulants in uncontrolled cardiovascular disease: Worsening hypertension and arrhythmias 2

Incidence of Drug-Drug Interactions

The incidence of drug-drug interactions increases from 10.9% with 2-4 drugs to 80.8% with ≥10 drugs, making medication review essential before adding any new agent 1

Special Population Adjustments

Severe Renal Impairment (CrCl <30 mL/min)

• Reduce LMWH dose or replace with UFH 1
• Avoid dabigatran if CrCl <30 mL/min/1.73 m² 1
• Avoid other DOACs if CrCl <15 mL/min/1.73 m² 1
• Target memantine dose of 5 mg twice daily if CrCl 5-29 mL/min 7

Patients ≥75 Years

• Consider ACE inhibitors/ARBs potentially inappropriate 1
• Use dabigatran and rivaroxaban with caution due to increased GI bleeding 1
• Consider warfarin potentially inappropriate for uncomplicated DVT >6 months or PE >12 months 1

Cardiovascular Disease History

• Avoid phentermine-topiramate ER due to lack of cardiovascular outcome trial data 1
• Ensure appropriate post-MI medications (aspirin, beta-blockers, ACE inhibitors/ARBs, statins) are prescribed 6
• Consider non-NSAID alternatives for pain management 6