Can Irbesartan and Valsartan Be Given Together?
No, irbesartan and valsartan should not be given together—both are angiotensin II receptor blockers (ARBs), and combining two ARBs constitutes dual blockade of the renin-angiotensin system (RAS), which significantly increases risks of hyperkalemia, hypotension, and acute renal dysfunction without providing additional therapeutic benefit. 1
Why Dual ARB Therapy Is Contraindicated
FDA-Labeled Contraindication
The FDA labeling for valsartan explicitly states that dual blockade of the RAS with angiotensin receptor blockers, ACE inhibitors, or aliskiren is associated with increased risks of:
- Hypotension
- Hyperkalemia
- Changes in renal function (including acute renal failure)
Most patients receiving the combination of two RAS inhibitors do not obtain any additional benefit compared to monotherapy. 1
Guideline Consensus
Multiple authoritative sources reinforce this prohibition:
The American College of Cardiology states that ARBs should not be used in combination with ACE inhibitors or aliskiren, as dual RAS blockade increases risks of hypotension, hyperkalemia, and acute kidney injury without additional benefit. 2
Telmisartan (another ARB) labeling explicitly states it must not be co-administered with ACE inhibitors or direct renin inhibitors because the combination increases the risk of hyperkalemia, symptomatic hypotension, and renal dysfunction without providing additional therapeutic benefit. 3
Clinical Evidence Against Dual ARB Use
The VALIANT trial demonstrated that combining valsartan with captopril (an ACE inhibitor) showed no increased benefit over captopril alone and had a higher incidence of discontinuation due to adverse effects. 4 While this studied ARB plus ACE inhibitor rather than two ARBs, the principle of avoiding dual RAS blockade applies equally.
Appropriate Alternatives
If Additional Blood Pressure Control Is Needed:
- Add hydrochlorothiazide to either irbesartan or valsartan—both are available as fixed-dose combinations (irbesartan/HCTZ as Avalide; valsartan/HCTZ). 5, 6
- The combination of an ARB with hydrochlorothiazide produces additive antihypertensive effects. 7, 6
If Switching Between ARBs:
- You may switch from one ARB to another (e.g., valsartan to irbesartan), but do not overlap them. 8
- Irbesartan has been shown to be more effective than valsartan in some comparative studies for absolute BP reduction and response rates. 7, 8
Monitoring Requirements If Patient Is on Any ARB
Regardless of which single ARB is chosen, monitor:
- Serum potassium and creatinine within 2-4 weeks of initiation, particularly in patients with chronic kidney disease or those taking potassium supplements. 2
- Avoid concomitant use with potassium-sparing diuretics, potassium supplements, or salt substitutes containing potassium, as these may lead to dangerous hyperkalemia. 1
Common Pitfall to Avoid
Do not attempt to combine two different ARBs thinking they will provide synergistic benefit—they act on the same receptor system and will only amplify adverse effects without improving outcomes. 1 The only appropriate combination involving ARBs is with agents from different drug classes (diuretics, calcium channel blockers, etc.), not with other RAS inhibitors.