Should a patient with angioedema and bilateral lower extremity edema, currently taking losartan (losartan potassium) 100 mg daily for hypertension, discontinue losartan and receive furosemide (Lasix) 40 mg?

From the Guidelines

Discontinuing losartan and administering furosemide 40 mg is the most appropriate course of action for a patient with angioedema and bilateral lower extremity edema, as losartan can exacerbate angioedema and furosemide can help reduce edema. According to the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1, angioedema is a serious adverse effect of angiotensin receptor blockers like losartan, representing a potentially life-threatening reaction that warrants immediate medication discontinuation. The guideline also recommends furosemide as a loop diuretic for patients with symptomatic heart failure or moderate-to-severe chronic kidney disease (CKD) 1.

Key Considerations

• Angioedema is a contraindication for continued use of losartan, as stated in the guideline 1.
• Furosemide 40 mg can help reduce bilateral lower extremity edema by increasing urinary sodium and water excretion.
• After discontinuing losartan, an alternative antihypertensive from a different class, such as a calcium channel blocker or a thiazide diuretic, should be considered.
• The patient should be monitored closely for resolution of angioedema and edema, as well as for blood pressure control.
• Kidney function and electrolytes should be checked before and after starting furosemide, as it can affect potassium, sodium, and renal function.

Alternative Antihypertensive Options

• Calcium channel blockers, such as amlodipine or felodipine, can be used as alternative antihypertensive agents, but may cause dose-related pedal edema 1.
• Thiazide diuretics, such as chlorthalidone or hydrochlorothiazide, can also be used, but require monitoring for hyponatremia, hypokalemia, uric acid, and calcium levels 1.

Patient Education

• The patient should be educated about the signs of worsening angioedema that would require emergency care.
• The patient should also be informed about the potential side effects of furosemide, such as hypokalemia, and the importance of regular monitoring of kidney function and electrolytes.

From the FDA Drug Label

Furosemide tablets may increase the ototoxic potential of aminoglycoside antibiotics, especially in the presence of impaired renal function Furosemide tablets combined with angiotensin converting enzyme inhibitors or angiotensin II receptor blockers may lead to severe hypotension and deterioration in renal function, including renal failure.

The patient is currently taking losartan, an angiotensin II receptor blocker.

• The FDA drug label recommends that Furosemide tablets combined with angiotensin converting enzyme inhibitors or angiotensin II receptor blockers may lead to severe hypotension and deterioration in renal function, including renal failure.
• An interruption or reduction in the dosage of Furosemide tablets, angiotensin converting enzyme inhibitors, or angiotensin receptor blockers may be necessary. Therefore, the patient should discontinue losartan and can receive furosemide (Lasix) 40 mg 2, 2.

From the Research

Losartan-Induced Angioedema

• Losartan, an angiotensin II receptor antagonist, has been associated with angioedema in several case reports 3, 4, 5, 6, 7.
• The mechanism of losartan-induced angioedema is not fully understood, but it may not be due to bradykinin excess 6.
• Angioedema due to losartan can occur even in patients with normal renal function and without prior exposure to ACE inhibitors 3.
• The onset of angioedema can occur within 24 hours to 16 months after the initiation of losartan therapy 7.

Discontinuation of Losartan and Alternative Treatment

• Given the patient's history of angioedema and bilateral lower extremity edema while taking losartan, discontinuation of losartan may be necessary to prevent further episodes of angioedema 3, 4, 5, 6, 7.
• Furosemide (Lasix) 40 mg may be considered as an alternative treatment for hypertension and edema, but its effectiveness and safety in this patient should be closely monitored.

Considerations for Patients with Angioedema

• Patients with a history of angioedema secondary to ACE inhibitors may not be safe alternatives for angiotensin receptor antagonists like losartan 6, 7.
• Clinicians should be aware of the potential risk of angioedema associated with losartan and monitor patients closely for signs and symptoms of angioedema 3, 4, 5, 6, 7.