When should Irbesartan (Angiotensin II receptor antagonist) be held?

When to Hold Irbesartan

Irbesartan must be discontinued immediately when pregnancy is detected, as it causes fetal renal dysfunction, oligohydramnios, and death when used in the second and third trimesters. 1

Absolute Contraindications Requiring Immediate Discontinuation

Pregnancy

• Discontinue irbesartan as soon as pregnancy is detected 1
• Use during second and third trimesters reduces fetal renal function and increases fetal/neonatal morbidity and death 1
• Resulting oligohydramnios can cause fetal lung hypoplasia, skull hypoplasia, anuria, hypotension, renal failure, and death 1
• If no alternative exists, perform serial ultrasound examinations to assess the intra-amniotic environment and discontinue if oligohydramnios develops 1

Severe Bilateral Renal Artery Stenosis

• Hold irbesartan in patients with severe bilateral renal artery stenosis due to risk of acute renal failure 2
• Angiotensin II is necessary for maintaining GFR when renal perfusion is compromised 2

History of Angioedema with ARBs

• Do not use irbesartan if the patient has a history of angioedema with ARBs 2
• Patients with angioedema from ACE inhibitors can receive an ARB only after waiting 6 weeks following ACE inhibitor discontinuation 2

Temporary Holds - Clinical Situations Requiring Suspension

Volume Depletion and Hypotension

• Hold irbesartan during states of significant volume depletion as angiotensin II is necessary for maintaining GFR 2
• Suspend during severe dehydration, aggressive diuresis, or symptomatic hypotension 2
• Can generally be safely restarted after volume status is restored and the acute episode resolves 2

Acute Kidney Injury

• Temporarily discontinue irbesartan if acute renal failure develops 2
• A rise in serum creatinine >30% from baseline warrants holding the medication 2
• ACE inhibitors and ARBs can be restarted after resolution of ARF, particularly if the underlying precipitating condition is managed 2

Severe Hyperkalemia

• Hold irbesartan if serum potassium exceeds 5.5 mmol/L 2
• If potassium is 5.0-5.5 mmol/L, reduce dose by 50% rather than completely discontinuing 2
• Monitor potassium levels closely, especially in patients with CKD or those on potassium supplements or potassium-sparing drugs 2, 3

Perioperative Considerations

• Consider holding irbesartan 24-48 hours before major cardiac surgery to reduce risk of profound hypotension during anesthesia 2
• ARBs are associated with greater blood pressure reduction during cardiac bypass surgery and increased vasopressor requirements 2
• However, evidence is conflicting, and the decision should weigh surgical risk against cardiovascular protection 2

Monitoring Parameters to Guide Holding Decisions

Renal Function Monitoring

• Check serum creatinine and potassium within 2-4 weeks after initiation or dose increase 3
• An initial rise in creatinine of 10-20% is expected and acceptable, representing hemodynamic changes rather than kidney injury 2
• Progressive increases beyond 30% warrant discontinuation 2

Combination Therapy Restrictions

• Never combine irbesartan with ACE inhibitors or direct renin inhibitors due to increased risk of hyperkalemia, hypotension, and renal dysfunction 2, 3
• This combination is explicitly not recommended by current guidelines 2

Special Populations

Nursing Mothers

• Discontinue either nursing or irbesartan due to potential adverse effects on the nursing infant 1
• Irbesartan or its metabolites are secreted in rat milk at low concentrations 1

Severe Renal Impairment

• Patients with GFR <30 mL/min require special consideration, though irbesartan is not absolutely contraindicated 3
• End-stage renal disease patients on dialysis can continue irbesartan but should avoid polyacrylonitrile dialysis membranes due to risk of anaphylactoid reactions 2