In patients with CKD, angiotensin-converting enzyme inhibitors (ACE inhibitors) and angiotensin receptor blockers (ARBs) have beneficial effects on proteinuria and slowing the progression of CKD. As patients with CKD may have a reduced ability to excrete potassium, they may need dietary advice on low potassium foods to use the doses required. If a patient has bilateral renal artery stenosis (a narrowing of the renal arteries requiring activation of the renin-angiotensin-system to overcome it), then ACE inhibitors and ARBs can cause acute kidney injury (AKI). For these reasons, it will be important to monitor renal function and potassium within one to two weeks of initiating ACE inhibitors and ARBs or a change in the dose prescribed. There is also a risk of CKD patients developing hyperkalaemia and AKI development when spironolactone is used.

Bendroflumethiazide may be ineffective if a patient’s GFR is less than 30mL/min/1.73m2 and furosemide may be preferred in CKD patients, especially if fluid retention and oedema are present. Dihydropyridine calcium-channel blockers may cause ankle swelling and patients with CKD may already have this symptom when the kidney’s ability to excrete fluid is impaired.

In practice, many antihypertensives are difficult to use in CKD and resistant hypertension develops that requires medicines such as alpha-blockers, e.g. doxazosin, moxonidine, minoxidil and methyldopa. Many of the antihypertensives have either a maximum dose or are contraindicated in the British National Formulary in severe renal impairment, but in practice they can be used at normal doses as long as they are monitored closely.