When Your Cardizem XR Prescription Can't Be Filled

Running out of a blood pressure medication isn't something you can shrug off. If you take Cardizem XR (Diltiazem extended-release) daily for hypertension or angina, a gap in treatment can cause your blood pressure to spike — sometimes dangerously.

If you can't find Cardizem XR at your pharmacy, the first step is to check availability at other locations using Medfinder. But if the drug truly isn't available in your area, you need to talk to your doctor about alternatives.

Here's what you should know about your options.

What Is Cardizem XR and How Does It Work?

Cardizem XR contains Diltiazem, a calcium channel blocker in the benzothiazepine class. It works by blocking calcium from entering the muscle cells of your heart and blood vessels. This causes blood vessels to relax and widen, which:

• Lowers blood pressure
• Reduces the heart's workload
• Improves blood flow to the heart muscle
• Slows the heart rate

The "XR" stands for extended-release, meaning the medication is released slowly over 24 hours so you only need to take it once a day. For a deeper dive, see How Does Cardizem XR Work?

Because Diltiazem has unique properties — it lowers blood pressure and slows heart rate — not all alternatives work exactly the same way. Your doctor will choose a replacement based on why you're taking Cardizem XR in the first place.

Alternative 1: Other Diltiazem Extended-Release Formulations

Before switching to a completely different drug, your doctor may try switching you to a different brand or generic version of Diltiazem ER. There are several on the market:

• Cartia XT — Extended-release capsules, once daily
• Tiazac — Extended-release capsules, once daily
• Cardizem CD — Extended-release capsules, once daily
• Cardizem LA — Extended-release tablets, once daily
• Taztia XT — Extended-release capsules, once daily
• Matzim LA — Extended-release tablets, once daily

Important: These formulations are not automatically interchangeable. Even though they all contain Diltiazem, they release the drug at different rates. Your doctor needs to confirm the switch and may adjust your dose. Never switch on your own.

Alternative 2: Verapamil ER (Calan SR, Verelan)

Verapamil is the other major non-dihydropyridine calcium channel blocker. Like Diltiazem, it lowers blood pressure and slows the heart rate, making it the closest therapeutic substitute for Cardizem XR.

Used for: High blood pressure, angina, heart rate control in atrial fibrillation

Key differences:

• Verapamil tends to cause more constipation than Diltiazem
• It has a stronger effect on slowing the heart rate
• Available as extended-release tablets and capsules
• Generic Verapamil ER is widely available and inexpensive ($4–$20 for a 30-day supply with a discount card)

Good option if: You need both blood pressure control and heart rate control, and Diltiazem formulations are unavailable.

Alternative 3: Amlodipine (Norvasc)

Amlodipine is a dihydropyridine calcium channel blocker — a different subclass than Diltiazem. It's one of the most commonly prescribed blood pressure medications in the world.

Used for: High blood pressure, chronic stable angina, vasospastic (Prinzmetal's) angina

Key differences:

• Amlodipine does not slow the heart rate — this is a significant difference from Cardizem XR
• It has a very long half-life, so it works smoothly over 24 hours
• Common side effects include ankle swelling (edema) and flushing
• Extremely affordable — generic Amlodipine costs as little as $4 for a 30-day supply

Good option if: You're taking Cardizem XR primarily for blood pressure (not heart rate control) and want a widely available, inexpensive alternative.

Alternative 4: Metoprolol Succinate ER (Toprol-XL)

Metoprolol Succinate is not a calcium channel blocker — it's a beta-blocker. However, it's a common alternative when patients need both blood pressure control and heart rate reduction.

Used for: High blood pressure, angina, heart failure, heart rate control

Key differences:

• Works by a completely different mechanism (blocks adrenaline receptors rather than calcium channels)
• Very effective at slowing heart rate
• May cause fatigue, cold hands, and depression in some patients
• Should not be combined with Diltiazem without careful monitoring (risk of severe bradycardia)
• Generic Metoprolol Succinate ER costs approximately $4–$15 for a 30-day supply

Good option if: You need heart rate control along with blood pressure management, and you don't have asthma or severe COPD (which are relative contraindications for beta-blockers).

What to Discuss With Your Doctor

Before switching from Cardizem XR to any alternative, make sure to discuss:

1. Why you're taking Cardizem XR — Is it primarily for blood pressure, angina, or heart rate control? The answer affects which alternative is best.
2. Your other medications — Some alternatives interact with drugs that Diltiazem doesn't, and vice versa. See Cardizem XR Drug Interactions for details.
3. Your medical history — Conditions like heart failure, asthma, or kidney disease may rule out certain alternatives.
4. Whether it's temporary — If the Cardizem XR shortage is expected to resolve soon, your doctor may prefer a short-term bridge rather than a permanent switch.

Don't Stop Taking Your Medication Without Talking to Your Doctor

This is critical: never stop taking Cardizem XR suddenly without medical guidance. While Diltiazem doesn't cause the same rebound effects as some beta-blockers, abruptly stopping blood pressure medication can cause a dangerous spike in blood pressure.

If you can't find your medication and can't reach your doctor right away, ask your pharmacist about an emergency supply to bridge the gap.

Final Thoughts

Losing access to your Cardizem XR prescription is stressful, but you have options. Start by searching for the drug at nearby pharmacies using Medfinder. If it's truly unavailable, work with your doctor to find the best alternative based on your specific health needs.

For help locating the drug, see How to Find Cardizem XR in Stock Near You. For savings tips, visit How to Save Money on Cardizem XR.