Hydrochlorothiazide vs. Diltiazem

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

Key Takeaways

  • Hydrochlorothiazide and diltiazem both lower blood pressure but work through different mechanisms — one removes excess fluid, the other relaxes blood vessels and slows the heart.

  • Diltiazem also treats angina and abnormal heart rhythms, while hydrochlorothiazide's approved uses are limited to blood pressure and fluid retention.

  • Hydrochlorothiazide is typically far less expensive, while diltiazem requires a multi-week dose titration that hydrochlorothiazide does not.

Hydrochlorothiazide vs. Diltiazem Drug Summary

Hydrochlorothiazide

Hydrochlorothiazide is a thiazide diuretic used to treat high blood pressure and fluid buildup from conditions like heart failure or liver disease. It works by helping the kidneys remove excess salt and water. It's taken as a once-daily tablet or capsule, alone or combined with other blood pressure medicines.

Diltiazem

Diltiazem is a non-dihydropyridine calcium channel blocker used to treat high blood pressure, angina, and certain fast heart rhythms. It relaxes blood vessels and slows the heart rate to reduce the heart's workload. It comes in immediate-release, extended-release, and IV forms, with oral tablets typically taken once daily.

Hydrochlorothiazide vs. Diltiazem Side Effects

Hydrochlorothiazide

Most common
Hypokalemia (not specified)
Hyperuricemia (not specified)
Hyperglycemia (not specified)
Hypotension (not specified)

Diltiazem

Most common
Edema lower-limb (up to 6.8%)
Dizziness (up to 6.4%)
Fatigue (up to 4.8%)
Bradycardia (up to 3.6%)

Hydrochlorothiazide vs. Diltiazem Dosage

Hydrochlorothiazide

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

Diltiazem

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 120-240 mg once daily Weeks 1-2
Maximum dose 540 mg once daily If needed
Dose changes 5 increases As tolerated

Hydrochlorothiazide vs. Diltiazem Indications

Hydrochlorothiazide

Hydrochlorothiazide is FDA-approved to manage hypertension, either alone or alongside other blood pressure medications. It's also approved for treating edema caused by heart failure, cirrhosis, kidney disease, or steroid and estrogen therapy. Off-label, it's sometimes used to prevent calcium-based kidney stones.

  • Lowers blood pressure alone or with other antihypertensives

  • Treats fluid retention from heart failure, cirrhosis, or kidney disease

  • Treats edema from corticosteroid or estrogen therapy

  • Off-label: helps prevent calcium kidney stones

Diltiazem

Diltiazem is FDA-approved to treat hypertension, chronic stable angina, and Prinzmetal's (vasospastic) angina. It's also approved to control heart rate in atrial fibrillation, atrial flutter, and paroxysmal supraventricular tachycardia. Off-label, it's sometimes used for migraine prevention or Raynaud's phenomenon.

  • Lowers blood pressure as monotherapy or combination therapy

  • Treats chronic stable and vasospastic (Prinzmetal's) angina

  • Controls heart rate in atrial fibrillation and flutter

  • Treats paroxysmal supraventricular tachycardia (PSVT)

Hydrochlorothiazide vs. Diltiazem Pros and Cons

Hydrochlorothiazide

Hydrochlorothiazide has decades of safety data and a simple once-daily dose that doesn't require titration. It's one of the least expensive blood pressure medications available, though it can cause electrolyte shifts that need periodic monitoring.

Pros

  • Decades of established real-world safety data

  • Simple once-daily dosing with no titration needed

  • Roughly $4 to $35 per month without insurance, notably cheaper than diltiazem

  • Often combined with other antihypertensives in single-pill combos

Cons

  • Can cause electrolyte imbalances that need monitoring

  • Increases skin cancer risk with long-term cumulative use

  • Not approved for angina or heart rhythm problems

  • Not recommended for use during pregnancy

Diltiazem

Diltiazem offers broader use beyond blood pressure, including angina and heart rhythm control, with both oral and IV formulations. It requires a gradual titration schedule and carries more cardiac contraindications, and it typically costs more than hydrochlorothiazide.

Pros

  • Also treats angina and controls heart rate in atrial fibrillation

  • Available as an IV infusion for urgent rate control

  • Multiple extended-release formulations allow flexible dosing

  • Off-label uses for migraine prevention and Raynaud's phenomenon

Cons

  • Requires gradual dose titration over several weeks

  • Contraindicated in certain heart block and sick sinus syndrome

  • Can worsen heart failure in patients with ventricular dysfunction

  • Roughly $18 to $125 per month without insurance, pricier than hydrochlorothiazide

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