Cardizem Is a Calcium Channel Blocker Used to Treat High Blood Pressure, Angina, and Certain Heart Rhythm Disorders

Cardizem (Diltiazem hydrochloride) is a prescription medication that belongs to a class of drugs called nondihydropyridine calcium channel blockers. It works by relaxing blood vessels and slowing the heart rate, which lowers blood pressure, reduces chest pain from angina, and helps control irregular heart rhythms.

Whether you've just been prescribed Cardizem or you're researching it for a family member, this guide covers everything you need to know — from what it treats to how much it costs in 2026.

What Is Cardizem?

Cardizem is the brand name for Diltiazem hydrochloride. It's classified as a nondihydropyridine calcium channel blocker (CCB) and a Group IV antiarrhythmic agent.

Key Facts

• Generic name: Diltiazem hydrochloride
• Brand names: Cardizem, Cardizem CD, Cardizem LA, Tiazac, Cartia XT, Dilacor XR, Dilt-XR, Matzim LA, Taztia XT
• Drug class: Nondihydropyridine calcium channel blocker
• Manufacturer: Bausch Health (brand Cardizem); multiple generic manufacturers including Teva, Mylan, Lupin, and Aurobindo
• Controlled substance: No — Cardizem is not a controlled substance
• Generic available: Yes — generic Diltiazem is widely available and significantly cheaper than brand-name Cardizem

What Is Cardizem Used For?

The FDA has approved Cardizem for several cardiovascular conditions:

• Hypertension (high blood pressure) — Cardizem relaxes blood vessels, reducing the force your heart has to pump against. It's used as a first-line or add-on treatment for high blood pressure.
• Chronic stable angina — By dilating coronary arteries and reducing the heart's workload, Cardizem helps prevent the chest pain that occurs with exertion in patients with coronary artery disease.
• Prinzmetal's (variant) angina — This type of angina is caused by coronary artery spasms. Cardizem directly relaxes the coronary arteries to prevent and relieve these spasms.
• Atrial fibrillation/flutter with rapid ventricular rate — Cardizem slows conduction through the AV node, which helps control a fast heart rate caused by atrial fibrillation or flutter.
• Paroxysmal supraventricular tachycardia (PSVT) — Cardizem can terminate and prevent episodes of this abnormal fast heart rhythm.

Off-Label Uses

Doctors sometimes prescribe Diltiazem for conditions not listed on the FDA label, including:

• Anal fissures — Topical compounded Diltiazem cream is used to relax the anal sphincter and promote healing.
• Migraine prophylaxis — Some studies suggest Diltiazem may help reduce migraine frequency.
• Pulmonary hypertension — In patients with a positive vasoreactivity test, Diltiazem may be used for Group 1 pulmonary arterial hypertension.
• Rate control in hyperthyroidism — When beta-blockers are contraindicated, Diltiazem can help control the fast heart rate associated with an overactive thyroid.

How Is Cardizem Taken?

Cardizem comes in several formulations, and how you take it depends on which one your doctor prescribes:

Immediate-Release Tablets

• Available doses: 30 mg, 60 mg, 90 mg, 120 mg
• How to take: Typically 3-4 times daily, before meals and at bedtime
• Notes: These require multiple daily doses, which can be less convenient but allow for more precise dose adjustments

Extended-Release Capsules and Tablets

• Available doses: 120 mg, 180 mg, 240 mg, 300 mg, 360 mg, 420 mg
• How to take: Once daily, at the same time each day
• Brand names: Cardizem CD, Cardizem LA, Tiazac, Cartia XT, Dilacor XR, Matzim LA, Taztia XT
• Important: Swallow whole — never crush, chew, or split extended-release forms. This can release too much medication at once and cause dangerous side effects.

Typical Dose Range

Most patients take 120-360 mg per day orally. The maximum dose is 480-540 mg per day depending on the formulation. Your doctor will typically start at a lower dose and increase gradually based on your response and tolerance.

Intravenous (IV) Diltiazem

IV Diltiazem is used in hospitals to quickly control a rapid heart rate. The typical dose is a 0.25 mg/kg bolus, followed by a continuous infusion of 5-15 mg/hr. This is administered by healthcare professionals and is not something patients manage at home.

Who Should Not Take Cardizem?

Cardizem is not safe for everyone. You should not take Cardizem if you have:

• Sick sinus syndrome without a functioning pacemaker
• Second- or third-degree AV block without a functioning pacemaker
• Severe hypotension (systolic blood pressure below 90 mmHg)
• Acute heart attack with pulmonary congestion
• Known allergy to Diltiazem or any ingredient in the formulation
• Wolff-Parkinson-White (WPW) syndrome with atrial fibrillation or flutter

Additionally, Cardizem should not be used at the same time as IV beta-blockers due to the risk of severe bradycardia and heart block.

If you're pregnant or breastfeeding, talk to your doctor before taking Cardizem. It has shown teratogenic effects in animal studies and is excreted in breast milk.

For a complete list of medications that interact with Cardizem, see our drug interactions guide.

How Much Does Cardizem Cost?

The cost of Cardizem varies significantly depending on whether you use brand-name or generic, which formulation you take, and whether you have insurance or use discount coupons.

• Generic Diltiazem IR tablets: $9-$20/month with coupons (like GoodRx or SingleCare)
• Generic Diltiazem ER capsules: $15-$60/month with coupons
• Without coupons: $55-$225/month
• Brand-name Cardizem: $300-$500+/month
• With insurance: Generic Diltiazem is typically Tier 1 or Tier 2, with copays of $0-$15. Prior authorization is generally not required for generics.

For detailed savings strategies, including coupons, discount cards, and patient assistance programs, see our complete guide: How to Save Money on Cardizem.

Final Thoughts

Cardizem (Diltiazem) is a well-established calcium channel blocker that's been helping patients manage high blood pressure, angina, and heart rhythm disorders for decades. With generic versions widely available and affordable, most patients can access this medication without difficulty.

To learn more, explore our guides on how Cardizem works, Cardizem side effects, and alternatives to Cardizem. If you need help finding Cardizem in stock near you, visit Medfinder.