Losartan vs. Diltiazem

See how Losartan and Diltiazem compare on approved uses, dosing, side effects, and cost.

Key Takeaways

  • Losartan blocks angiotensin II to relax blood vessels, while diltiazem blocks calcium channels in the heart and blood vessel walls, so the two drugs lower blood pressure through different pathways.

  • Diltiazem is FDA-approved for more conditions than losartan, including angina and heart rhythm control, while losartan carries a specific kidney-protective indication for diabetic nephropathy.

  • Diltiazem can slow heart rate and is contraindicated in certain heart rhythm disorders, while losartan does not affect heart rate or conduction at all.

Losartan vs. Diltiazem Drug Summary

Losartan

Losartan is an angiotensin II receptor blocker (ARB) used to treat high blood pressure, slow diabetic kidney disease in people with type 2 diabetes, and lower stroke risk in patients with hypertension and an enlarged heart muscle. It comes as a single oral tablet taken once a day, usually starting at 50 mg.

Diltiazem

Diltiazem is a calcium channel blocker used to treat high blood pressure, chronic and vasospastic angina, and to control heart rate in atrial fibrillation and other fast heart rhythms. It is taken as an oral tablet once daily for long-term conditions, or given as an IV infusion in the hospital for rapid rate control.

Losartan vs. Diltiazem Side Effects

Losartan

Most common
Upper respiratory infection (up to 8%)
Dizziness (up to 3%)
Nasal congestion (up to 2%)
Back pain (up to 2%)

Diltiazem

Most common
Dizziness (up to 6.4%)
Fatigue (up to 4.8%)
Bradycardia (up to 3.6%)
Cough (up to 2%)

Losartan vs. Diltiazem Dosage

Losartan

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 25 mg once daily At the start
Maximum dose 100 mg once daily If needed
Dose changes 2 increases As tolerated

Diltiazem

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 0.25 mg/kg IV bolus At the start
Maximum dose 480 mg once daily If needed
Dose changes 7 increases As tolerated

Losartan vs. Diltiazem Indications

Losartan

Losartan is FDA-approved to lower blood pressure in adults and children over 6, to slow the progression of diabetic kidney disease in people with type 2 diabetes, and to reduce stroke risk in patients who have both hypertension and an enlarged heart muscle. It is not approved for angina or heart rhythm control.

  • Hypertension in adults and children over 6

  • Diabetic nephropathy with type 2 diabetes

  • Stroke risk reduction in hypertension with left ventricular hypertrophy

  • This stroke-risk benefit has not been shown in Black patients

Diltiazem

Diltiazem is FDA-approved to lower blood pressure, treat chronic stable and vasospastic angina, and control heart rate in atrial fibrillation, atrial flutter, and paroxysmal supraventricular tachycardia. It is also used off-label for migraine prevention, Raynaud's phenomenon, and pulmonary hypertension.

  • Hypertension (oral tablet or capsule)

  • Chronic stable and vasospastic (Prinzmetal's) angina

  • Atrial fibrillation and atrial flutter rate control

  • Paroxysmal supraventricular tachycardia, usually via IV

Losartan vs. Diltiazem Pros and Cons

Losartan

Losartan is a simple once-daily pill with a narrower set of approved uses focused on blood pressure and kidney protection. It is widely covered as a low-cost generic and does not carry the heart-rhythm warnings that come with calcium channel blockers.

Pros

  • Once-daily dosing with no titration needed for most patients

  • Also protects the kidneys in diabetic nephropathy

  • Added stroke-risk reduction benefit in hypertension with an enlarged heart

Cons

  • Not approved for angina or heart rhythm disorders

  • Can raise potassium levels, requiring periodic blood tests

  • Not safe during pregnancy

  • Should be avoided with bilateral renal artery narrowing

Diltiazem

Diltiazem covers a broader range of heart conditions than losartan, including angina and arrhythmias, and offers both an IV form for hospital use and oral forms for daily control. That flexibility comes with more cardiac monitoring requirements and contraindications tied to the heart's electrical system.

Pros

  • Treats angina and heart rhythm problems in addition to blood pressure

  • IV formulation available for rapid rate control in urgent settings

  • Multiple oral formulations (immediate, sustained, extended-release) for flexible dosing

Cons

  • Contraindicated in sick sinus syndrome and certain AV blocks without a pacemaker

  • Can cause bradycardia and slowed heart conduction, requiring monitoring

  • Higher rates of dizziness and swelling than losartan

  • Can worsen heart failure in patients with reduced heart pumping function

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