Dosing Considerations for Common Medications in Renal Disease

Metformina

• The National Kidney Foundation recommends a standard dose of metformina for patients with a TFG ≥60 ml/min/1.73m², without the need for dose adjustments 1, 2
• For patients with a TFG of 45-59 ml/min/1.73m², the American Diabetes Association suggests considering a dose reduction in certain conditions, such as advanced age or concomitant liver disease 1, 3
• A TFG of 30-44 ml/min/1.73m² requires a dose reduction to half of the maximum recommended dose, as recommended by the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines 1, 4
• Metformina is contraindicated in patients with a TFG <30 ml/min/1.73m², according to the National Kidney Foundation 1, 2
• The American College of Clinical Pharmacy recommends monitoring renal function at least every 3-6 months in patients with a TFG <60 ml/min/1.73m² 1
• The National Kidney Foundation also recommends monitoring for vitamin B12 deficiency in patients on long-term metformina therapy (>4 years) 1

Losartán

• The American Heart Association recommends no initial dose adjustment for losartán in patients with a TFG ≥30 ml/min/1.73m² 2
• For patients with a TFG <30 ml/min/1.73m², the European Renal Association suggests initiating with a lower dose (25 mg/day) and titrating slowly according to response 2
• The use of losartán in dialysis patients is limited, and caution is advised, as recommended by the National Kidney Foundation 3

Hidroclorotiazida (HCTZ)

• The European Society of Hypertension recommends that HCTZ is effective without dose adjustment in patients with a TFG >30 ml/min/1.73m² 1
• For patients with a TFG <30 ml/min/1.73m², HCTZ is generally ineffective and not recommended, according to the American College of Cardiology 4
• HCTZ is contraindicated in patients with a TFG <15 ml/min/1.73m², as recommended by the National Kidney Foundation 2

Nifedipino

• The American College of Cardiology notes that nifedipino is primarily metabolized by the liver, and its metabolism is not significantly affected by renal function 1

Algoritmo para ajuste de medicamentos en enfermedad renal crónica

• The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines recommend evaluating the patient's current TFG and verifying absolute contraindications (e.g., metformina with TFG <30, HCTZ with TFG <15) 1
• The National Kidney Foundation suggests adjusting doses according to specific TFG ranges for each medication 1
• The American College of Clinical Pharmacy recommends reevaluating medication with each significant change in renal function 1

Metformin Dosing with eGFR 30-39 mL/min/1.73m²

Metformin Dosing Based on Kidney Function

• The Kidney International guideline recommends reducing the metformin dose to half the maximum recommended dose, to 500mg daily, for patients with an eGFR of 30-39 mL/min/1.73m², representing moderate to severe renal impairment 5
• More frequent monitoring of kidney function is required, every 3-6 months, for patients with an eGFR of 30-39 mL/min/1.73m² 5

Safety Considerations

• With an eGFR of 30-39, patients are at the lower end of the acceptable range for metformin use, according to the Kidney International guideline 6, 5

Monitoring Requirements

• The Kidney International guideline recommends monitoring for signs of vitamin B12 deficiency if patients have been on metformin for more than 4 years 5

Special Precautions

• The American Journal of Kidney Diseases recommends implementing "sick day rules" to stop metformin during serious intercurrent illness that increases the risk of acute kidney injury 7

Alternative Medication Options

• The Kidney International guideline suggests considering adding a GLP-1 receptor agonist if glycemic targets are not met with the reduced metformin dose 5
• For patients with eGFR <30 mL/min/1.73m², alternative diabetes medications include DPP-4 inhibitors, insulin, sulfonylureas, TZDs, or alpha-glucosidase inhibitors, according to the Kidney International guideline 8, 9

Dapagliflozin and Metformin Combination Therapy

Renal Function Considerations

• The American Diabetes Association and the National Kidney Foundation recommend that metformin is contraindicated when eGFR falls below 30 mL/min/1.73m² for glucose-lowering purposes, and dapagliflozin is not recommended for initiation when eGFR is below 45 mL/min/1.73m² 10
• For patients with eGFR 45-59 mL/min/1.73m², the Mayo Clinic recommends continuing the current metformin dose but monitoring renal function every 3-6 months, with consideration of dose reduction in elderly patients or those with liver disease 10
• The Kidney International guidelines suggest that dapagliflozin can be used at a dose of 10 mg daily for cardiovascular and renal protection in patients with eGFR 25-44 mL/min/1.73m², but initiation is not recommended below eGFR 25 11, 12

Dose Adjustments and Contraindications

• The Mayo Clinic Proceedings state that dapagliflozin is contraindicated in dialysis patients, and the Kidney International guidelines recommend that initiation is not recommended when eGFR is below 25 mL/min/1.73m² 10, 11, 12
• The Kidney International guidelines recommend that for patients already on dapagliflozin for heart failure or CKD indications, it may be continued when eGFR falls below 25 mL/min/1.73m², but initiation is not recommended 11, 12

Dapagliflozin and Metformin Dosing in Patients with Impaired Renal Function

Metformin Dosing Adjustments

• The Kidney International guideline recommends adjusting metformin dose based on eGFR, with a maximum total daily dose of 1000 mg (500 mg BID) if eGFR is 30-44 mL/min/1.73 m² 13, 14
• If eGFR is 45-59 mL/min/1.73 m², the current metformin dose should be continued without increase, and dose reduction should be considered if the patient is elderly or has liver disease 13, 14, 15
• If eGFR is <30 mL/min/1.73 m², metformin should be stopped immediately as it is contraindicated 13, 14

Dapagliflozin Initiation and Monitoring

• The European Heart Journal recommends adding dapagliflozin 10 mg daily for patients with diabetes, impaired renal function, and proteinuria, if eGFR is ≥25 mL/min/1.73 m² 13, 14, 16
• Dapagliflozin initiation is independent of glycemic control, and it reduces the risk of sustained eGFR decline, ESKD, CV death, and heart failure hospitalization 13, 14
• The Kidney International guideline recommends assessing and correcting volume depletion before initiating dapagliflozin, and monitoring renal function every 3-6 months 13, 14

Special Precautions

• The Kidney International guideline recommends counseling patients about symptoms of volume depletion and hypotension, and following up on volume status after drug initiation 13
• Dapagliflozin causes an acute, reversible decrease in eGFR within the first week, which is not an indication to discontinue therapy 13
• The Kidney International guideline recommends monitoring vitamin B12 if metformin is continued for more than 4 years 13, 14