How should I adjust medication dosages for patients with CKD, particularly those on antihypertensives and diuretics?

For patients with chronic kidney disease (CKD), medication dosages, particularly for antihypertensive medications, require careful adjustment and monitoring.

Antihypertensive Medications (ACE Inhibitors and ARBs):

• In adults with CKD and an albumin:creatinine ratio (ACR) over 30 mg/mmol, or those with CKD and diabetes (type 1 or type 2) with an ACR of 3 mg/mmol or more, an angiotensin-receptor blocker (ARB) or an angiotensin-converting enzyme (ACE) inhibitor should be offered ⁵.
• These medications should be titrated to the highest licensed dose that the person can tolerate ⁵.
• Before starting renin–angiotensin system (RAS) antagonists (ACE inhibitors or ARBs), serum potassium concentrations and estimated glomerular filtration rate (eGFR) should be measured ⁵.
• These measurements must be repeated between 1 and 2 weeks after starting RAS antagonists and after each dose increase ⁵.
• It is important to explain to patients the significance of achieving the optimal tolerated dose of RAS antagonists and the need for monitoring eGFR and serum potassium safely ⁵.
• RAS antagonists should not be routinely offered if the pre-treatment serum potassium concentration is greater than 5.0 mmol/litre ⁵. If hyperkalaemia prevents their use, other factors promoting hyperkalaemia should be assessed and treated, and serum potassium rechecked ⁵.
• A combination of ACE inhibitors and ARBs should not be used to treat hypertension or offered to adults with CKD ³,⁵.
• Blood pressure targets for adults with CKD vary based on ACR: aim for a clinic systolic blood pressure below 140 mmHg (target range 120 to 139 mmHg) and a clinic diastolic blood pressure below 90 mmHg if ACR is under 70 mg/mmol ⁵. If ACR is 70 mg/mmol or more, aim for a clinic systolic blood pressure below 130 mmHg (target range 120 to 129 mmHg) and a clinic diastolic blood pressure below 80 mmHg ⁵.

Diuretics:

• If a calcium-channel blocker (CCB) is not tolerated, for example, due to oedema, a thiazide-like diuretic, such as indapamide, should be offered ³.
• When initiating or changing diuretic treatment for hypertension, a thiazide-like diuretic, such as indapamide, is preferred over conventional thiazide diuretics like bendroflumethiazide or hydrochlorothiazide ³.

General Medication Considerations and "Sick Day" Guidance:

• There may be a need to temporarily stop some medications, including ACE inhibitors or ARBs, if a person has an intercurrent illness, particularly if there is a risk of dehydration ⁴.
• People at risk of acute kidney injury (AKI) should seek medical advice if they have an intercurrent illness and/or risk of dehydration, so appropriate advice about specific medications can be given ⁴,⁶.
• Indiscriminate chronic use of over-the-counter (OTC) non-steroidal anti-inflammatory drugs (NSAIDs) should be discouraged due to an associated higher risk of kidney failure ¹,².
• Salt substitutes containing potassium chloride should not be used by people with kidney disease or those taking certain antihypertensive drugs, such as ACE inhibitors and ARBs; instead, advise salt reduction ¹,².