CKD-friendly dosages and cautions
Summary
This is a summary on medications that need to be adjusted according to the renal function of the patient.
Basics
In this article, we will be discussing some important points regarding the usage of medications in chronic kidney disease. I will limit the discussion to common drugs used in public institutions, especially at a district level or clinics.
Diuretics
- Loop diuretics are preferred when the eGFR < 30 ml/min per 1.73 m^2. However, loop diuretics can be used at all eGFR values.
- Thiazides are usually more effective at eGFR values > 30ml/min/1.73m^2.
- Potassium-sparing diuretics should not be used when the eGFR is <30 ml/min per 1.73 m^2.
- Need to be careful, since excessive diuretic use may result in acute kidney injury.
- Diuretics are also associated with various side effects.
- Hypokalemia: This can occur with thiazide and loop diuretics.
- Hyperkalemia: This can occur with K+ sparing diuretics.
RAAS Inhibitors
- These agents are essential for the management of CKD. Therefore, they are NOT contraindicated. However, there are a few important points to mention.
- Hypotension is common with the use of RAAS inhibitors (eg ACE-I or ARBs), resulting in acute kidney injury (AKI).
- The addition of an NSAID to a patient with RAAS inhibitors increases the risk of AKI.
- Hyperkalemia: This can occur with the use of RAAS inhibitors.
Antihyperglycemic Agents
- The dose of Metformin is eGFR dependent. This is because at low eGFR levels there is an increased risk of lactic acidosis. Patients with CKD are at increased risk of hypoglycemia, especially due to sulphonylureas and insulin.
- Metformin:
- eGFR ≥ 45 : Normal dose
- eGFR 30 – 44: Dose adjustment is required. However, if the patient is a newly diagnosed diabetic patient then Metformin should NOT be initiated on these patients.
- eGFR ≤ 29: Use is not recommended.
- Glimepiride:
- eGFR ≥ 15: Normal dose.
- eGFR < 15: There is no manufacturer-specific recommendation for use or dose adjustment.
- Glipizide:
- Used in all eGFR levels at the normal dose.
- Insulin:
- There is an increased risk of hypoglycemia. Therefore patients who have CKD need to have their insulin doses adjusted correctly.
Anti-Retrovirals
- Tenofovir:
- eGFR ≥ 50: Normal dose.
- eGFR < 50: Dose adjustment is required.
- However, when the eGFR <50 then it is not recommended. Rather change to AZT (if there is no risk of anemia) or ABC. If this is not possible, tenofovir will need to be given at different intervals (not every 24 hours).
- Lamivudine:
- eGFR ≥ 50: Normal dose.
- eGFR < 50: Dose adjustment is required.
- eGFR 10 – 50: 150mg PO first dose, then 50 – 150mg PO OD.
- eGFR <10: 50mg PO first dose, then 25 – 50mg PO OD.
- Emtricitabine:
- eGFR ≥ 50: Normal dose.
- eGFR < 50: Dose adjustment is required.
Cautionary Notes
- Aminoglycosides: These agents are nephrotoxic and ototoxic.
- Digoxin: There is an increased risk of toxicity, such as arrhythmias.
- Warfarin: There is an increased risk of bleeding.
- Anti-epileptics: We need to monitor these agents closely.
- NSAIDs: Can cause kidney injury, sodium and/or potassium retention as well as interstitial nephropathy. Should avoid using NSAIDs with diuretics or RAAS inhibitors.
- Iodinated contrast media: This is nephrotoxic.
- Herbals: Such as licorice, noni juice, St. John’s wort, and Ginkgo biloba should be avoided.
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