How should I adjust the common inpatient drugs—antihypertensives, diuretics, anticoagulants, insulin, antibiotics, and statins—in a typical 65‑plus‑year‑old adult with hypertension, chronic kidney disease, heart failure, diabetes, receiving anticoagulation and antibiotics, based on age, renal and hepatic function, blood pressure, heart rate, volume status, and recent laboratory abnormalities?

Medication Adjustment in Hospitalized Older Adults with Multiple Comorbidities

Antihypertensives

For elderly patients ≥65 years with hypertension, target blood pressure <140/90 mmHg as the minimum goal, with <130/80 mmHg considered if well-tolerated and high cardiovascular risk is present. 1

Initial Assessment

• Measure blood pressure in both sitting and standing positions to detect orthostatic hypotension (drop ≥20 mmHg systolic or ≥10 mmHg diastolic within 1-3 minutes of standing) 1
• For patients ≥80 years, continue antihypertensive therapy lifelong if tolerated; do not discontinue based on age alone 1
• In frail elderly ≥85 years, consider monotherapy initially (preferably amlodipine 2.5-5 mg daily) rather than combination therapy 1

Medication Selection by Age and Comorbidity

• First-line for patients ≥55 years: Calcium channel blocker (amlodipine 2.5-5 mg daily) OR thiazide-like diuretic (chlorthalidone 12.5 mg or indapamide 1.25 mg daily) 2, 1
• For patients <55 years: ACE inhibitor or ARB as first-line 2
• With diabetes: ACE inhibitor or ARB preferred; target <140/90 mmHg (not <130/80 mmHg, as ACCORD trial showed no additional benefit) 2, 1
• With chronic kidney disease: ACE inhibitor or ARB as first-line; monitor creatinine and potassium within 1-2 weeks 1, 3

Dose Titration Strategy

• Start low, go slow: Use half the standard starting dose in elderly patients to minimize hypotension and falls 1, 4
• Uptitrate every 2-4 weeks until target blood pressure achieved 2
• A creatinine rise up to 20% after starting ACE inhibitor/ARB is acceptable and does not require discontinuation 1, 3
• Alternate adjustments between drug classes (e.g., ACE inhibitor one visit, calcium channel blocker the next) rather than maximizing one agent 2

Specific Adjustments for Renal Impairment

• ACE inhibitors/ARBs: Check creatinine and potassium within 1-2 weeks of initiation or dose change; acceptable creatinine rise ≤20% 1, 3
• Thiazide diuretics: Lose efficacy when eGFR <30 mL/min; switch to loop diuretic 5
• Thiazide-like diuretics (chlorthalidone, indapamide): Remain effective even with moderate renal impairment 5
• Spironolactone: Use with extreme caution if eGFR <45 mL/min due to hyperkalemia risk; check potassium within 1 week 2, 5

Common Pitfalls

• Do not use chlorthalidone >12.5 mg in elderly patients; doses ≥25 mg increase hypokalemia risk 3-fold and eliminate cardiovascular protection 1
• Do not use beta-blockers as first-line in elderly unless compelling indication (heart failure, post-MI, angina); they are less effective for stroke prevention 1
• Do not withhold treatment based on asymptomatic orthostatic hypotension; this does not predict adverse outcomes 1

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Diuretics

Adjust diuretic dose based on volume status (jugular venous pressure, peripheral edema, lung crackles) and daily weights, not solely on laboratory values.

Loop Diuretics (Furosemide, Torsemide)

• Volume overload with normal renal function: Furosemide 20-40 mg IV/PO daily or twice daily 2
• Volume overload with CKD (eGFR 30-60): Furosemide 40-80 mg IV/PO twice daily 2
• Volume overload with CKD (eGFR <30): Furosemide 80-160 mg IV/PO twice daily or continuous infusion 2
• Monitor potassium, magnesium, and creatinine every 2-3 days during active diuresis 2
• If inadequate response after 2-3 days, double the dose rather than increasing frequency 2

Thiazide and Thiazide-Like Diuretics

• Hypertension with eGFR ≥30: Chlorthalidone 12.5 mg daily (maximum in elderly) or indapamide 1.25 mg daily 1, 5
• eGFR <30: Switch to loop diuretic; thiazides ineffective 5
• Monitor potassium and sodium within 2-4 weeks of initiation 2, 5

Potassium-Sparing Diuretics

• Spironolactone for resistant hypertension: 25 mg daily if potassium <4.5 mEq/L and eGFR >45 mL/min 2, 5
• Avoid if: eGFR <30 mL/min, potassium >5.0 mEq/L, or concurrent ACE inhibitor/ARB in elderly 2
• Check potassium within 1 week, then monthly for 3 months 2, 5

Medications to Avoid in Elderly with CKD

• Triamterene: Do not use if creatinine clearance <30 mL/min 2
• Spironolactone: Do not use if creatinine clearance <30 mL/min 2

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Anticoagulants

Adjust anticoagulant dosing based on renal function (CrCl by Cockcroft-Gault), body weight, age, and bleeding risk; monitor INR or anti-Xa activity as indicated.

Warfarin (VKA)

• Underweight or obesity class ≥2: Require more frequent INR monitoring during initiation and maintenance 2
• Post-bariatric surgery: Resume with 30% reduction in weekly dose compared to pre-surgery; monitor INR frequently for 12 months 2
• Elderly: Start with lower doses (2.5-5 mg daily); target INR 2.0-3.0 for most indications 2
• Check INR every 2-3 days during initiation, then weekly until stable, then monthly 2

Direct Oral Anticoagulants (DOACs)

Apixaban

• Standard dose: 5 mg twice daily 2
• Reduce to 2.5 mg twice daily if: Age ≥80 years AND (body weight ≤60 kg OR serum creatinine ≥133 μmol/L [1.5 mg/dL]) 2
• Severe underweight: Consider monitoring peak/trough levels or switch to warfarin 2
• Obesity class ≥3: Insufficient data; consider monitoring peak/trough levels 2

Rivaroxaban

• Atrial fibrillation: 20 mg daily with evening meal 2
• CrCl 15-50 mL/min: 15 mg daily 2
• Acute VTE: 15 mg twice daily for 21 days, then 20 mg daily 2
• Obesity class ≥3: Unknown efficacy/safety; consider monitoring peak/trough levels 2

Edoxaban

• Standard dose: 60 mg daily 2
• Reduce to 30 mg daily if: Body weight ≤60 kg OR CrCl 15-50 mL/min 2
• Severe underweight: Consider monitoring peak/trough levels or switch to warfarin 2

Dabigatran

• Standard dose: 150 mg twice daily 2
• Reduce to 110 mg twice daily if: Age ≥80 years OR eGFR <50 mL/min OR high bleeding risk 2
• Severe underweight: Consider monitoring with ecarin clotting time (ECT); if levels too low, switch to warfarin 2

Low Molecular Weight Heparin (LMWH)

Enoxaparin

• VTE prophylaxis, normal weight: 40 mg subcutaneous daily 2
• VTE prophylaxis, obesity class ≥2: 40 mg subcutaneous twice daily 2
• VTE treatment: 1 mg/kg subcutaneous twice daily 2
• VTE treatment, obesity class ≥3: Reduce dose by ~20%; consider measuring anti-Xa activity (target 0.6-1.0 IU/mL) 2
• CrCl <30 mL/min: Reduce dose by 50% or use alternative anticoagulant 2

Dalteparin

• VTE prophylaxis: 5000 IU subcutaneous daily 2
• VTE prophylaxis, obesity class ≥2: 5000 IU subcutaneous twice daily 2
• VTE treatment: 200 IU/kg subcutaneous daily or divided twice daily 2

Monitoring Parameters

• Warfarin: INR every 2-3 days during initiation, then weekly until stable, then monthly 2
• DOACs: Renal function every 3-6 months (more frequently if CrCl <60 mL/min) 2
• LMWH in obesity or renal impairment: Anti-Xa activity 4 hours post-dose 2

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Insulin

Adjust insulin doses based on blood glucose patterns, nutritional intake, and renal function; reduce total daily dose by 25-50% when eGFR <30 mL/min.

Basal Insulin Adjustment

• Fasting glucose 80-130 mg/dL: No change 2
• Fasting glucose >130 mg/dL on 2 consecutive days: Increase basal insulin by 10-20% or 2-4 units 2
• Fasting glucose <70 mg/dL: Decrease basal insulin by 10-20% or 2-4 units 2
• CKD stage 4-5 (eGFR <30): Reduce basal insulin dose by 25-50% due to decreased renal clearance 2

Prandial Insulin Adjustment

• Pre-meal glucose 80-130 mg/dL: No change 2
• 2-hour post-meal glucose >180 mg/dL: Increase prandial insulin by 1-2 units or 10% 2
• 2-hour post-meal glucose <70 mg/dL: Decrease prandial insulin by 1-2 units or 10% 2
• NPO or poor oral intake: Hold prandial insulin; continue basal insulin at reduced dose (50-75% of usual) 2

Correction (Sliding Scale) Insulin

• Use correction insulin in addition to scheduled insulin, not as sole therapy 2
• Insulin-sensitive patients (elderly, renal impairment): 1 unit lowers glucose by 50-80 mg/dL 2
• Insulin-resistant patients (obesity, steroids): 1 unit lowers glucose by 20-30 mg/dL 2

Special Considerations

• Acute illness or infection: May require 20-50% increase in total daily insulin dose 2
• Corticosteroid therapy: Primarily affects post-prandial glucose; increase prandial insulin by 50-100% 2
• Hypoglycemia (<70 mg/dL): Reduce total daily insulin dose by 10-20%; identify and address cause 2

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Antibiotics

Adjust antibiotic doses based on renal function (CrCl by Cockcroft-Gault) and hepatic function; extend dosing intervals or reduce doses as indicated.

Renally Cleared Antibiotics Requiring Dose Adjustment

Ciprofloxacin

• CrCl >50 mL/min: 400 mg IV every 12 hours or 500-750 mg PO every 12 hours 2
• CrCl 30-50 mL/min: 400 mg IV every 18-24 hours or 250-500 mg PO every 12 hours 2
• CrCl <30 mL/min: 400 mg IV every 24 hours or 250-500 mg PO every 24 hours 2

Trimethoprim-Sulfamethoxazole (Cotrimoxazole)

• CrCl >30 mL/min: Standard dosing (1-2 double-strength tablets every 12 hours) 2
• CrCl 15-30 mL/min: Reduce dose by 50% 2
• CrCl <15 mL/min: Avoid use 2

Vancomycin

• Loading dose: 25-30 mg/kg IV (actual body weight) regardless of renal function 6
• Maintenance dosing by CrCl:
  • CrCl >80 mL/min: 15-20 mg/kg every 8-12 hours 6
  • CrCl 50-80 mL/min: 15-20 mg/kg every 12-24 hours 6
  • CrCl 10-50 mL/min: 15-20 mg/kg every 24-48 hours 6
  • CrCl <10 mL/min: Individualize based on trough levels 6
• Monitor trough levels before 4th dose; target 10-20 mcg/mL (15-20 mcg/mL for serious infections) 6

Acyclovir/Valacyclovir

• Acyclovir, CrCl >50 mL/min: 5-10 mg/kg IV every 8 hours 2
• Acyclovir, CrCl 25-50 mL/min: 5-10 mg/kg IV every 12 hours 2
• Acyclovir, CrCl 10-25 mL/min: 5-10 mg/kg IV every 24 hours 2
• Valacyclovir, CrCl <50 mL/min: Reduce dose or extend interval per package insert 2

Gabapentin (if used for neuropathic pain)

• CrCl >60 mL/min: 300-1200 mg three times daily 2
• CrCl 30-60 mL/min: 200-700 mg twice daily 2
• CrCl 15-30 mL/min: 200-700 mg once daily 2
• CrCl <15 mL/min: 100-300 mg once daily 2

Antibiotics to Avoid in Elderly with CKD

• Nitrofurantoin: Do not use if CrCl <30 mL/min (ineffective and increased toxicity risk) 2
• Meperidine: Do not use if CrCl <30 mL/min (accumulation of toxic metabolite normeperidine causing seizures) 2

Hepatically Cleared Antibiotics

• Ceftriaxone, moxifloxacin, doxycycline, azithromycin: No dose adjustment needed for renal impairment 6
• Metronidazole: Reduce dose by 50% in severe hepatic impairment (Child-Pugh C) 6

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Statins

Continue statin therapy in elderly patients with established cardiovascular disease; statins are not beneficial when prescribed solely for heart failure without other indications. 2

Continuation vs. Discontinuation

• Established ASCVD or diabetes: Continue statin therapy regardless of age 2
• Heart failure without other indications: Statins not beneficial; consider discontinuation 2
• Limited life expectancy (<1 year): Consider discontinuation for deprescribing 2

Dose Adjustment for Renal Impairment

• Atorvastatin, fluvastatin: No dose adjustment needed for any level of renal impairment 6
• Rosuvastatin: Start with 5 mg daily if eGFR <30 mL/min; maximum 10 mg daily 6
• Simvastatin, pravastatin, lovastatin: Start with lowest dose if eGFR <30 mL/min 6

Drug Interactions

• Simvastatin + amlodipine: Maximum simvastatin dose 20 mg daily 6
• Simvastatin + diltiazem or verapamil: Maximum simvastatin dose 10 mg daily 6
• Any statin + fibrate: Increased myopathy risk; monitor CK and symptoms closely 6

Monitoring

• Baseline: ALT, AST, CK 2
• Follow-up: Repeat ALT/AST at 12 weeks if dose increased; otherwise annually 2
• Myopathy symptoms (muscle pain, weakness): Check CK immediately; discontinue if CK >10× upper limit of normal 2

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Critical Laboratory-Based Adjustments

Hyperkalemia (K >5.0 mEq/L)

• Mild (5.0-5.5 mEq/L): Reduce or hold potassium-sparing diuretics; reduce ACE inhibitor/ARB dose by 50% 2, 7
• Moderate (5.5-6.0 mEq/L): Hold ACE inhibitor/ARB and potassium-sparing diuretics; recheck in 2-3 days 2, 7
• Severe (>6.0 mEq/L): Discontinue ACE inhibitor/ARB and potassium-sparing diuretics; treat acutely; recheck daily 2, 7

Hypokalemia (K <3.5 mEq/L)

• Mild (3.0-3.5 mEq/L): Increase dietary potassium; consider potassium supplement 20-40 mEq daily 1
• Moderate (<3.0 mEq/L): Potassium supplement 40-80 mEq daily in divided doses; recheck in 2-3 days 1
• On chlorthalidone >12.5 mg: Reduce to 12.5 mg or switch to alternative diuretic 1

Acute Kidney Injury (Creatinine Rise >0.3 mg/dL in 48 hours or >50% from baseline)

• Hold: ACE inhibitors, ARBs, NSAIDs, diuretics (if volume depleted) 7, 3
• Assess volume status: If hypovolemic, give IV fluids; if euvolemic/hypervolemic, continue diuretics 7
• Recheck creatinine in 24-48 hours: If improving, cautiously restart ACE inhibitor/ARB at 50% dose 3
• If creatinine rise >20% after starting ACE inhibitor/ARB: Consider renal artery stenosis; obtain renal ultrasound with Doppler 3

Hypotension (SBP <100 mmHg or symptomatic)

• Symptomatic orthostatic hypotension: Hold or reduce antihypertensives; assess for volume depletion 1, 7
• Asymptomatic low BP: No adjustment needed if patient tolerates well 1
• SBP <90 mmHg: Hold all antihypertensives; give IV fluids if appropriate; recheck BP in 2-4 hours 1

Bradycardia (HR <50 bpm)

• Asymptomatic: Reduce or hold beta-blocker; consider switching to calcium channel blocker 1
• Symptomatic or HR <45 bpm: Hold beta-blocker and non-dihydropyridine calcium channel blockers; obtain ECG 1