Complete List of Angiotensin II Receptor Blockers (ARBs)
Angiotensin II Receptor Blockers (ARBs) include azilsartan, candesartan, eprosartan, irbesartan, losartan, olmesartan, telmisartan, and valsartan. 1, 2
Available ARBs and Dosing Information
ARBs are a class of medications that block the effects of angiotensin II by antagonizing the angiotensin II type 1 receptor, leading to vasodilation and decreased blood pressure 2.
Currently Available ARBs:
- Azilsartan: 40-80 mg once daily 1
- Candesartan: 8-32 mg once daily 1
- Eprosartan: 600-800 mg once or twice daily 1
- Irbesartan: 150-300 mg once daily 1
- Losartan: 50-100 mg once or twice daily 1
- Olmesartan: 20-40 mg once daily 1
- Telmisartan: 20-80 mg once daily 1, 3
- Valsartan: 80-320 mg once daily 1
Pharmacological Properties of ARBs
ARBs differ in their pharmacokinetic and pharmacodynamic properties:
- Prodrugs: Azilsartan, candesartan, and olmesartan are administered as prodrugs that require activation 2
- Active metabolites: Losartan has an active metabolite (EXP3174) that contributes significantly to its antihypertensive effect 4
- Bioavailability: Ranges from 13% (eprosartan) to 60-80% (irbesartan) 4
- Protein binding: Most ARBs have high plasma protein binding (95-100%), with irbesartan having the lowest (90%) 4
- Duration of action: All currently available ARBs provide 24-hour blood pressure control with once-daily dosing 5
Clinical Applications
ARBs are indicated for:
- Hypertension: All ARBs are FDA-approved for treatment of hypertension 1, 3, 6
- Heart failure: Candesartan, losartan, and valsartan have demonstrated benefits in heart failure 1
- Diabetic nephropathy: ARBs reduce microalbuminuria and improve renal function in diabetic patients 1
- Cardiovascular risk reduction: Some ARBs, like telmisartan, are indicated for cardiovascular risk reduction in patients unable to take ACE inhibitors 3
Advantages and Side Effects
Advantages:
- Alternative to ACE inhibitors: ARBs are particularly useful in patients who develop cough or angioedema with ACE inhibitors 1, 5
- Tolerability: ARBs generally have a side effect profile similar to placebo 5
Side Effects and Precautions:
- Hyperkalemia: Increased risk in patients with CKD or those on potassium-sparing medications 1
- Renal dysfunction: Risk of acute renal failure in patients with severe bilateral renal artery stenosis 1
- Pregnancy: All ARBs should be avoided during pregnancy due to fetal toxicity 1, 6
- Angioedema: Although less common than with ACE inhibitors, angioedema can still occur with ARBs 1
Comparative Efficacy
While all ARBs effectively lower blood pressure, some studies suggest differences in potency:
- Based on daily mg dose, the relative potency follows: candesartan > telmisartan ≈ losartan > irbesartan ≈ valsartan > eprosartan 4
- Head-to-head trials have suggested that olmesartan may provide greater blood pressure reduction than losartan, valsartan, irbesartan, and candesartan at their respective recommended doses 7
ARBs remain an important class of medications for cardiovascular and renal protection, with their specific selection often guided by comorbidities, dosing convenience, and individual patient response 1.