What are the uses and side effects of Losartan (angiotensin II receptor antagonist) in treating Hypertension?

Losartan: Uses, Effectiveness, and Side Effects

Losartan is primarily indicated for treating hypertension in adults and children over 6 years of age, with additional benefits for diabetic nephropathy and cardiovascular protection in patients with left ventricular hypertrophy. 1

Primary Uses of Losartan

• Hypertension management: Lowers blood pressure effectively as monotherapy or in combination with other antihypertensive medications 1
• Diabetic nephropathy: Reduces progression of kidney disease in patients with type 2 diabetes with elevated serum creatinine and proteinuria 1, 2
• Cardiovascular protection: Reduces stroke risk in hypertensive patients with left ventricular hypertrophy (though this benefit may not apply to Black patients) 1

Dosing Information

• Starting dose: 50 mg once daily 1
• Maintenance dose: Can be increased to 100 mg once daily if blood pressure response is insufficient 3
• For inadequate response to monotherapy: Addition of hydrochlorothiazide is recommended 1

Blood Pressure Lowering Effect

Losartan effectively lowers blood pressure by:

• Blocking angiotensin II receptors (specifically AT1 receptors) 4
• Providing similar efficacy to other antihypertensive classes including ACE inhibitors, beta-blockers, and calcium channel blockers 4, 5
• Reducing systolic blood pressure by up to 25 mmHg and diastolic blood pressure by up to 18 mmHg in patients with severe hypertension 6

Benefits Beyond Blood Pressure Control

Losartan offers several advantages beyond simple blood pressure reduction:

1. Renoprotective effects:

   • Reduces the rate of progression of nephropathy in type 2 diabetes 1, 7
   • Decreases the incidence of end-stage renal disease by 28% 3
   • Reduces proteinuria by up to 36% at 12 months, independent of blood pressure control 8

2. Cardiovascular benefits:

   • Reduces the risk of stroke in hypertensive patients with LVH 1
   • Decreases cardiovascular events by 24% in hypertensive patients with LVH compared to atenolol 3
   • Reduces hospitalization for heart failure in diabetic patients with nephropathy 2

Common Side Effects

According to the FDA label, the most common side effects (occurring in ≥2% of patients and more frequently than placebo) include 1:

• Dizziness (3% vs. 2% with placebo)
• Upper respiratory infection (8% vs. 7%)
• Nasal congestion (2% vs. 1%)
• Back pain (2% vs. 1%)

Less Common Side Effects

Less common adverse reactions include 1:

• Headache and sleep disorders
• Palpitations
• Gastrointestinal symptoms (abdominal pain, nausea, vomiting)
• Skin reactions (rash, pruritus)
• Myalgia and arthralgia

Advantages Over ACE Inhibitors

Losartan has a significantly lower incidence of cough compared to ACE inhibitors:

• In patients who previously experienced ACE inhibitor-induced cough, losartan caused cough in only 17-29% of patients compared to 62-69% with lisinopril 1
• Better overall tolerability profile with lower withdrawal rates due to adverse events 5

Special Considerations

1. Renal impairment: Monitor renal function and serum potassium levels when initiating therapy 3

2. Hepatic disease: May require dose adjustment in patients with hepatic impairment 4

3. Pregnancy: Contraindicated during pregnancy due to potential fetal harm 3

4. Elderly patients: No dosage adjustment required based on age alone 5

Losartan represents an effective option for hypertension management with additional benefits for specific patient populations, particularly those with diabetic nephropathy or left ventricular hypertrophy.