What adjustments should be made to the medication regimen of a patient with impaired renal function, hyperkalemia, dementia, and respiratory disease, who is currently taking Anurity Ellipta (fluticasone furoate/vilanterol), bupropion, donepezil, duloxetine, Nexium (esomeprazole), losartan, metoprolol, tamsulosin, and solifenacin?

Medication Adjustments for Hyperkalemia and Impaired Renal Function

Immediate Priority: Address Hyperkalemia (K+ 5.6 mEq/L)

Your patient's potassium of 5.6 mEq/L with a GFR of 56 mL/min requires immediate intervention, primarily by discontinuing or reducing losartan, as this ARB is the most likely culprit for hyperkalemia in the setting of stage 3a CKD. 1, 2

Critical Medication Causing Hyperkalemia

Losartan must be discontinued or dose-reduced immediately because:

• ARBs like losartan increase serum potassium by blocking aldosterone, particularly dangerous when GFR <60 mL/min 2, 3
• The FDA label explicitly warns that losartan co-administered with other potassium-affecting drugs results in hyperkalemia, requiring potassium monitoring 2
• With K+ >5.0 mEq/L and GFR 56, guidelines recommend either discontinuing the ARB or initiating a potassium-lowering agent 4
• Dual blockade concerns: If patient were on an ACE inhibitor alongside losartan, this would be contraindicated and dramatically increase hyperkalemia risk 2

Immediate Management Steps

1. Stop losartan temporarily until potassium normalizes to 4.0-5.0 mEq/L 1, 4
2. Recheck potassium and creatinine within 3-7 days after stopping losartan 1
3. Implement dietary potassium restriction: Avoid high-potassium foods, salt substitutes, and NSAIDs 4, 3
4. Consider a potassium binder (patiromer or sodium zirconium cyclosilicate) if you need to maintain the ARB for cardiac/renal protection 4, 3

Medications Requiring Dose Adjustment for GFR 56 mL/min

Duloxetine

Duloxetine requires caution but no mandatory dose reduction at GFR 56 mL/min, though it should be avoided if GFR drops below 30 mL/min 5. Monitor for increased side effects as renal impairment can alter drug metabolism 5.

Solifenacin

Solifenacin maximum dose should be limited to 5 mg daily in moderate renal impairment (GFR 30-60 mL/min), as higher doses increase risk of anticholinergic toxicity 5.

Metoprolol

No dose adjustment required for metoprolol at this level of renal function, as it is primarily hepatically metabolized 5.

Medications Safe to Continue Without Adjustment

• Anurity Ellipta (fluticasone/vilanterol): No renal dose adjustment needed; inhaled corticosteroids are not renally cleared 6
• Bupropion: No dose adjustment at GFR 56, though caution advised if GFR <30 mL/min 5
• Donepezil: No renal dose adjustment required 6
• Nexium (esomeprazole): No dose adjustment needed 6
• Tamsulosin: No renal dose adjustment required 5

Critical Drug Interactions Exacerbating Hyperkalemia

Avoid NSAIDs entirely (including over-the-counter ibuprofen, naproxen) as they:

• Worsen renal function and dramatically increase hyperkalemia risk when combined with ARBs 2, 7
• Can precipitate acute kidney injury in patients with baseline renal impairment 2, 5
• Block the antihypertensive effect of losartan 2

Monitoring Protocol After Adjustments

1. Within 3-7 days: Recheck potassium, sodium, creatinine, and GFR 1
2. At 1-2 weeks: Repeat electrolytes if initial values abnormal 1
3. Monthly for 3 months, then every 3-6 months: Continue monitoring potassium and renal function 1
4. Target potassium range: 4.0-5.0 mEq/L to minimize cardiac risk 1, 4

Alternative Antihypertensive Strategy

Once potassium normalizes, consider:

• Restarting losartan at reduced dose (25 mg daily) with concurrent potassium binder if needed for cardiac/renal protection 4, 2
• Switching to a calcium channel blocker (amlodipine 2.5-10 mg daily) which doesn't affect potassium 1
• Adding or increasing metoprolol for blood pressure control without potassium effects 1

Common Pitfalls to Avoid

• Never continue losartan at current dose with K+ 5.6 mEq/L - this risks life-threatening arrhythmias 1, 2
• Don't add potassium-sparing diuretics (spironolactone, triamterene) with baseline hyperkalemia and ARB use 1, 2
• Avoid potassium supplements or salt substitutes while on losartan 4, 2
• Don't assume creatinine 1.3 reflects true GFR in elderly or low muscle mass patients; use calculated GFR 1
• Never restart losartan without confirming potassium <5.0 mEq/L 1, 4