What medication adjustments are needed for a patient with impaired renal function taking HCTZ (Hydrochlorothiazide), amlodipine, losartan, apixaban, pantoprazole, and Dayvigo (Lemborexant)?

Medication Adjustments for Severe Renal Impairment (CrCl 28 mL/min)

This patient requires immediate discontinuation of HCTZ and dose reduction of apixaban; losartan and amlodipine can continue with caution, while pantoprazole and Dayvigo require no adjustment.

Critical Changes Required

Discontinue Hydrochlorothiazide (HCTZ)

• HCTZ 50 mg daily must be stopped immediately. 1
• Thiazide diuretics become ineffective when GFR falls below 30 mL/min and may precipitate azotemia in patients with impaired renal function 2
• Loop diuretics (furosemide, torsemide, or bumetanide) are preferred in patients with moderate-to-severe CKD (GFR <30 mL/min) 1
• Switch to a loop diuretic such as furosemide 20-40 mg daily or torsemide 5-10 mg daily for blood pressure control and any volume management 1

Reduce Apixaban Dose

• Apixaban must be reduced from 5 mg BID to 2.5 mg BID 1
• The FDA-approved dose reduction criteria for apixaban include: serum creatinine ≥133 micromol/L (approximately 1.5 mg/dL) in combination with age ≥80 years OR body weight <60 kg 1
• This patient meets the creatinine criterion (223 micromol/L = 2.52 mg/dL) and at age 78 is approaching the age threshold 1
• Given the CrCl of 28 mL/min, the 2.5 mg BID dose is appropriate to reduce bleeding risk while maintaining stroke prevention 1
• Monitor closely for bleeding complications, as patients with severe renal impairment have significantly elevated bleeding risk even with dose adjustment 1

Medications Requiring Caution but No Immediate Dose Change

Losartan

• Losartan 25 mg daily can continue at the current dose 3
• No dose adjustment is necessary in patients with renal impairment unless the patient is also volume depleted 3
• However, monitor closely for hyperkalemia and further decline in renal function 1
• Do not stop losartan if serum creatinine increases up to 30% from baseline, as this is expected and acceptable 1
• Stop losartan if: renal function continues to worsen beyond 30% increase, refractory hyperkalemia develops, or symptomatic hypotension occurs 1
• In the context of metastatic cancer affecting the kidney, the benefit of continued RAAS blockade must be weighed against the risk of further renal deterioration 1

Amlodipine

• Amlodipine 2.5 mg daily requires no dose adjustment 1
• Calcium channel blockers are not renally eliminated and are safe in renal impairment 1
• Continue current dose for blood pressure control 1

Medications Requiring No Adjustment

Pantoprazole

• Pantoprazole 40 mg PRN requires no dose adjustment 4
• Pharmacokinetic parameters for pantoprazole are similar in patients with severe renal impairment compared to healthy subjects 4
• There is no renal excretion of unchanged pantoprazole 4

Dayvigo (Lemborexant)

• Dayvigo 5 mg PRN requires no dose adjustment based on renal function alone
• Lemborexant is primarily hepatically metabolized with minimal renal elimination
• Continue current PRN dosing for insomnia management

Critical Monitoring Parameters

Immediate Laboratory Monitoring

• Recheck serum creatinine, potassium, and sodium within 3-7 days after medication changes 1
• Monitor for signs of volume depletion after switching from HCTZ to loop diuretic 1
• Check anti-Xa levels if bleeding occurs on reduced-dose apixaban, though routine monitoring is not required 1

Ongoing Surveillance

• Assess renal function every 1-3 months given progressive metastatic disease and CKD stage 4 1
• Monitor blood pressure closely after diuretic switch to ensure adequate control 1
• Watch for hyperkalemia (target potassium <5.5 mEq/L) given continued losartan use in severe renal impairment 1

Common Pitfalls to Avoid

• Do not continue thiazide diuretics when GFR <30 mL/min - they are ineffective and potentially harmful 1, 2
• Do not use full-dose apixaban (5 mg BID) with severe renal impairment and elevated creatinine - this significantly increases major bleeding risk 1
• Do not abruptly stop losartan due to concerns about rising creatinine unless increase exceeds 30% or hyperkalemia develops - modest creatinine elevation is expected and acceptable 1
• Avoid combining ACE inhibitors, ARBs, and renin inhibitors - this is potentially harmful and contraindicated 1
• Do not prescribe potassium supplements while on losartan without close monitoring, as this increases hyperkalemia risk 1