ARB Initiation and Monitoring

Angiotensin receptor blockers block the AT1 receptor and are used in hypertension, heart failure with reduced ejection fraction, diabetic kidney disease with albuminuria and as the alternative when an ACE inhibitor causes cough. They have the same contraindications for pregnancy, bilateral renal artery stenosis and hyperkalaemia, and need the same potassium and creatinine checks. Cough is rare and angioedema uncommon.

Baseline. Seated and standing blood pressure, creatinine, eGFR, potassium and pregnancy status.

Combination. Do not combine with an ACE inhibitor outside specialist heart failure care, because of hyperkalaemia and kidney injury.

Losartan. Hypertension 50 mg orally once daily, maximum 100 mg daily. Heart failure 25 to 50 mg once daily, target 150 mg daily. It also lowers urate.

Candesartan. Hypertension 8 mg once daily, increased to 16 mg and then 32 mg daily. Heart failure 4 mg once daily, target 32 mg daily.

Valsartan. Hypertension 80 to 160 mg once daily, maximum 320 mg. Heart failure or after myocardial infarction 40 mg twice daily, target 160 mg twice daily.

Telmisartan. 40 mg once daily, maximum 80 mg daily.

Irbesartan. 150 mg once daily, maximum 300 mg daily.

Special groups. In older adults start at half dose. In creatinine clearance under 30 mL/min start losartan at 25 mg and candesartan at 4 mg. In hepatic impairment start candesartan at 4 mg and limit telmisartan to 40 mg daily, and avoid in severe disease or biliary obstruction. In pregnancy stop at confirmation. In breastfeeding use enalapril or captopril instead, as data on angiotensin receptor blockers are limited.

In African ancestry, the pressure response is smaller alone, so combine with amlodipine or a thiazide-like diuretic. After ACE inhibitor angioedema, use only with specialist advice.

Monitoring. Pressure, potassium and creatinine at 1 to 2 weeks and after each increase. Accept a creatinine rise up to 30%. Reduce the dose for potassium of 5.5 to 5.9 mmol/L and stop for 6.0 mmol/L or over.

Titration. Increase every 2 to 4 weeks, and every 2 weeks in heart failure.

Interactions. NSAIDs, potassium supplements, trimethoprim, spironolactone and lithium.

Sick day rule. Withhold during vomiting, diarrhoea or poor intake.

Switching. Move from an ACE inhibitor for cough on the same day without a washout. Move to sacubitril valsartan without a gap.

Stopping. Stop for angioedema, potassium of 6.0 mmol/L or over, symptomatic hypotension that persists after diuretic reduction, or a creatinine rise over 30% not explained by volume depletion.

Common errors. Adding an ACE inhibitor to an angiotensin receptor blocker, high starting doses, missing repeat bloods.

Referral and escalation. Refer for a sustained creatinine rise over 30%, recurrent hyperkalaemia, or suspected renal artery stenosis.