Cardizem® (Diltiazem) Uses, Dosing, and Safety Overview

What Cardizem® Is and How It Works

Diltiazem is a calcium channel blocker used for high blood pressure and chronic stable angina. It relaxes blood vessels and slows heart rate by blocking L‑type calcium channels in the heart and arterial smooth muscle. Lower vascular resistance reduces blood pressure, and slower atrioventricular conduction helps angina and certain rate-control needs. Many people compare Diltiazem price options to manage therapy without insurance.

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Oral forms include immediate‑release tablets, and extended‑release capsules or tablets labeled as diltiazem HCl ER, diltiazem 24h ER CD, XR, or SR depending on release profile. Typical once‑daily ER strengths include 120 mg, 180 mg, 240 mg, 300 mg, and 360 mg. Immediate‑release tablets are taken in divided doses through the day. Clinicians also use diltiazem to control ventricular rate in atrial fibrillation; dosing and formulation are individualized.

For hypertension and angina, extended‑release products allow once‑daily dosing and steady blood levels. Immediate‑release products may suit certain rate‑control scenarios or patients who require flexible titration. Choice among diltiazem ER brands (CD, XR, LA) depends on release characteristics and prescriber preference.

Dosage and Usage

• Initiation for hypertension (ER): common starting dose 120–180 mg once daily. Titrate every 1–2 weeks toward 240–360 mg once daily as tolerated. Some formulations permit up to 480 mg/day per labeling.
• Initiation for angina (ER): typical starting dose 120–180 mg once daily. Usual maintenance 240–360 mg once daily, adjusted by response and tolerability.
• Immediate‑release tablets: may start at 30 mg four times daily. Titrate in divided doses; usual total daily dose 180–360 mg/day. Maximum labeled dose varies by product.
• Atrial fibrillation rate control: maintenance commonly uses ER 120–360 mg once daily per prescriber guidance. Individualize based on heart rate and comorbidities.
• Administration: ER capsules/tablets are swallowed whole; do not crush or chew. Take consistently with or without food. Immediate‑release tablets are taken in divided doses.
• Missed dose (ER): take when remembered unless close to the next dose. Do not double doses.
• Missed dose (IR): take when remembered if not near the next scheduled dose; avoid doubling.
• Switching products: ER products differ in release profiles; milligram‑to‑milligram substitutions are not always equivalent. Prescriber direction is required when switching.
• Grapefruit: avoid grapefruit or grapefruit juice because it can raise diltiazem levels.
• Stopping: therapy is often long term; prescribers may adjust or taper based on response.

• Store at 20–25 °C (68–77 °F); brief excursions 15–30 °C (59–86 °F) are usually acceptable.
• Keep tablets/capsules dry in the original container with the label.
• Avoid bathroom storage and excess heat. Protect from moisture and direct sunlight.
• For travel, keep medicine in carry‑on luggage with your prescription label.
• Bring enough supply for the trip plus a few extra days. Do not mix old and new bottles.
• Use a pill organizer if helpful, and set reminders on your phone.

Benefits and Savings

Diltiazem lowers blood pressure, helps prevent angina episodes, and may improve exercise tolerance. Extended‑release dosing supports once‑daily convenience. Multiple strengths, including diltiazem 120 mg, diltiazem 180 mg, and diltiazem 360 mg, allow careful titration.

Ordering from YouDrugstore gives access to Canadian pricing, often 60–80% less than typical US prices. Many patients compare Diltiazem cost without insurance across strengths, then choose multi‑month supplies to reduce per‑month cost. You can also turn on reorder reminders in your account to avoid gaps.

Looking for an offer? See our current diltiazem coupon updates on the promotions page.

Side Effects and Safety

• Common: headache, dizziness, fatigue, flushing, edema (ankle swelling), nausea, abdominal discomfort, constipation.
• Less common: rash, pruritus, palpitations, dry mouth, sleep changes.
• Lab changes: mild elevations in liver enzymes may occur and are usually reversible.
• Cardiac effects: bradycardia, first‑degree AV block, hypotension; risk increases with higher doses or interacting drugs.
• Drug interactions: beta‑blockers increase risk of bradycardia/heart block; diltiazem inhibits CYP3A4 and can raise levels of simvastatin, lovastatin, cyclosporine, and others; digoxin levels may rise; avoid grapefruit.

Serious reactions are uncommon but include severe hypotension, heart block, worsening heart failure in reduced ejection fraction, liver injury, and severe skin reactions. Diltiazem is contraindicated in sick sinus syndrome or second/third‑degree AV block without a pacemaker, severe hypotension, and acute myocardial infarction with pulmonary congestion. Prescribers use caution in heart failure; see labeling for details.

Onset Time

Immediate‑release tablets begin lowering blood pressure within hours of the first dose. Extended‑release products reach a steady effect over several days, with the full antihypertensive response often seen within 1–2 weeks after a dose change. Angina control may improve within days as the dose is optimized. Heart‑rate control for atrial fibrillation is usually evident within the first doses under clinical guidance.

Compare With Alternatives

Amlodipine is a dihydropyridine calcium channel blocker that lowers blood pressure by arterial vasodilation without slowing heart rate. It is taken once daily and tends to cause more ankle swelling and less bradycardia than diltiazem. See Amlodipine for details.

Verapamil is another non‑dihydropyridine that slows heart rate more than diltiazem in some patients and may cause constipation. It shares interaction concerns via CYP3A4 and with beta‑blockers. Some patients who do not tolerate verapamil may do better on diltiazem, and vice versa.

Norvasc is the amlodipine brand. Patients stabilized on the brand may prefer to remain on it for consistency. Compare options here: Norvasc®. For related conditions, browse High Blood Pressure and Angina.

Combination Therapy

• Hypertension: often combined with an ACE inhibitor or ARB to enhance blood pressure control.
• With thiazide diuretics: adds complementary natriuretic and vasodilatory effects.
• Angina: can be paired with long‑acting nitrates; monitor for hypotension.
• Beta‑blockers: combination can deepen bradycardia/AV block; prescribers may adjust doses and monitor ECG and heart rate.
• Digoxin: diltiazem may increase digoxin levels; monitoring may be required.
• Statins: dose limits apply for simvastatin/lovastatin when used with diltiazem.

Patient Suitability and Cost-Saving Tips

Candidates include adults with essential hypertension or chronic stable angina who need a calcium channel blocker with rate‑control properties. It can be considered for certain atrial fibrillation rate‑control strategies. Those with a history of heart block, severe hypotension, or decompensated heart failure with reduced ejection fraction may not be suitable.

Pregnancy and breastfeeding require individualized assessment. Liver or kidney impairment may call for careful dosing and monitoring. Older adults may need lower starting doses and slower titration.

To reduce costs, choose generic diltiazem HCl ER where appropriate. Compare strengths such as diltiazem ER 180 mg vs 240 mg to match prescriber directions while watching total monthly spend. Multi‑month supplies (for example, 90 days) can lower per‑month costs when permitted. Reorder reminders in your account help maintain continuity. Many shoppers review the cost of diltiazem 120 mg or diltiazem hcl er 180 mg to estimate total spend. If paying without insurance, Canadian pricing can offer predictable savings.

Authoritative Sources

Cardizem LA (diltiazem) US Prescribing Information (FDA)

Health Canada Drug Product Database: Diltiazem Hydrochloride

Tiazac (diltiazem) US Prescribing Information

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This material is educational and does not replace advice from a qualified healthcare professional. Always follow your prescriber’s instructions and the product labeling.