Should I discontinue losartan immediately?

Should Losartan Be Discontinued Immediately?

No, losartan should not be discontinued abruptly in most clinical scenarios, as sudden withdrawal can lead to clinical deterioration in patients with heart failure or hypertension. 1

When Immediate Discontinuation IS Required

Losartan must be stopped immediately in the following situations:

• Pregnancy detected – Discontinue as soon as pregnancy is confirmed, as losartan causes fetal toxicity (skull hypoplasia, anuria, hypotension, renal failure, death) during second and third trimesters. 2

• Angioedema – Any signs of angioedema (facial/tongue/throat swelling, difficulty breathing) require immediate cessation and emergency management. 2

• Acute renal failure – If serum creatinine rises >30% above baseline or acute kidney injury develops, discontinue losartan promptly. 2 This is particularly critical in patients with bilateral renal artery stenosis, severe heart failure, or volume depletion where renal function depends on angiotensin II. 2, 3

• Severe hyperkalemia – If serum potassium rises to dangerous levels (typically >6.0 mEq/L with ECG changes), stop losartan immediately while treating the hyperkalemia. 2

• Symptomatic hypotension – In volume- or salt-depleted patients who develop severe symptomatic hypotension after starting losartan, hold the medication and correct volume status before considering reinitiation. 2

When Gradual Discontinuation or Continuation Is Appropriate

• Heart failure patients – The 2013 ACC/AHA heart failure guidelines explicitly warn that "abrupt withdrawal of treatment with an ACE inhibitor can lead to clinical deterioration and should be avoided." 1 This same principle applies to ARBs like losartan, which are recommended alternatives when ACE inhibitors are not tolerated. 1

• Chronic hypertension management – In stable hypertensive patients without contraindications, losartan should be continued as part of long-term blood pressure control. 4 The 2017 ACC/AHA guidelines list losartan as a primary antihypertensive agent for chronic intracerebral hemorrhage survivors. 4

• Tolerability issues – If side effects develop (dizziness, mild creatinine elevation 10-20%), consider dose reduction rather than abrupt discontinuation. 1, 2

Monitoring Parameters Before Deciding to Discontinue

Check the following before making a discontinuation decision:

• Renal function – Measure serum creatinine and compare to baseline. A rise of 10-20% is acceptable; >30% warrants discontinuation. 2, 3

• Serum potassium – Monitor periodically; hyperkalemia risk is increased with chronic kidney disease or concomitant potassium-sparing agents. 2

• Blood pressure – Assess for symptomatic hypotension, especially in volume-depleted patients. 2

• Pregnancy status – In women of childbearing age, confirm pregnancy status before continuing therapy. 2

Common Pitfalls to Avoid

• Do not stop losartan abruptly in heart failure patients – This can precipitate acute decompensation. 1 If discontinuation is necessary, taper gradually while monitoring closely.

• Do not assume losartan is safer than ACE inhibitors for renal function – Evidence shows losartan causes identical rates of renal dysfunction (10.5%) as ACE inhibitors in elderly heart failure patients. 3 Both classes should be avoided in bilateral renal artery stenosis. 2, 3

• Do not combine losartan with ACE inhibitors or direct renin inhibitors – Simultaneous use increases risks of hyperkalemia, hypotension, and renal dysfunction without added benefit. 1, 5

• Do not forget to correct volume depletion first – In patients on high-dose diuretics or with diarrhea/vomiting, correct volume status before deciding whether hypotension is truly drug-related. 2

Practical Algorithm for Decision-Making

1. Identify absolute contraindications (pregnancy, angioedema, bilateral renal artery stenosis) → Stop immediately. 2

2. Check renal function and potassium → If creatinine >30% above baseline or K+ dangerously elevated → Stop and reassess. 2

3. Assess volume status → If hypotensive and volume-depleted → Hold losartan, correct volume, then reassess need. 2

4. Evaluate indication → If heart failure or chronic hypertension with good tolerance → Continue with monitoring. 1, 4

5. Consider dose adjustment → If mild side effects or borderline lab abnormalities → Reduce dose rather than stop. 1