Cardizem, Cardizem La

Introduction

Written by Sarah Lewis, PharmD
Medically reviewed by Victor Nguyen, PharmD, MBA
Updated on August 25, 2023

Diltiazem (dil TYE a zem) is a generic medication prescribed for high blood pressure, angina (chest pain), and heart rhythm problems. Diltiazem belongs to a group of drugs called calcium channel blockers.

These approved uses differ based on the form of diltiazem your doctor prescribes.

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Side effects of diltiazem

Diltiazem may cause mild or serious side effects. More common mild side effects of diltiazem and its serious side effects are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age, overall health, and any other medications you take.

To learn more about diltiazem’s side effects, ask your doctor or pharmacist. You can also refer to the prescribing information for diltiazem listed in the “Resources” section.

Mild side effects

More common mild side effects reported with some forms of diltiazem are listed below. These side effects may differ based on the form of diltiazem you take.

This article doesn’t include all possible mild side effects of the drug. To learn more about diltiazem’s side effects based on the form, refer to the prescribing information for diltiazem listed in the “Resources” section.

With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects are bothersome, tell your doctor or pharmacist. They may be able to suggest ways to manage them.

Diltiazem oral tablet’s mild side effects include:

• dizziness
• edema (fluid buildup and swelling, often affecting the lower legs and feet)
• headache
• nausea
• mild allergic reaction*

Diltiazem injection given into the vein’s mild side effects include:

• dizziness
• flushing
• injection site reactions
• low blood pressure
• mild allergic reaction*

* For details about this side effect, see the “Interactions and warnings for diltiazem” section.

Serious side effects

Serious side effects of diltiazem are listed below. These side effects may differ based on the form of diltiazem you take.

This article doesn’t include all possible serious side effects of the drug. To learn more about diltiazem’s side effects based on the form, refer to the prescribing information for diltiazem listed in the “Resources” section.

With many drugs, serious side effects are possible but not common. If you have serious side effects from this drug, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.

In general, diltiazem’s serious side effects include:

• liver damage
• low blood pressure that causes symptoms and requires treatment
• slow heart rate
• worsening heart failure
• severe allergic reaction *

* For details about this side effect, see the “Interactions and warnings for diltiazem” section.

Common questions about diltiazem

Below you’ll find answers to a few commonly asked questions about diltiazem.

Is diltiazem safe for older adults?

Possibly. Older adults often process drugs more slowly than younger adults. This is because liver and kidney function tend to decline with age. As a result, usual dosages of drugs can produce high drug levels in older adults. This can lead to increased or more severe side effects. With diltiazem, doctors may start older adults on lower dosages to reduce this risk.

If you have concerns about whether diltiazem is right for your age, talk with your doctor.

Does diltiazem come in a topical cream?

No, diltiazem doesn’t typically come in a topical cream. But a compounding pharmacy can make diltiazem cream if a doctor prescribes it. Doctors use diltiazem cream to help heal anal fissures (tears in the anus) and hemorrhoids that have developed blood clots.

You can learn more about diltiazem cream by talking with your doctor or pharmacist.

Do I need to take diltiazem on an empty stomach?

No, you don’t need to take diltiazem on an empty stomach. You can take it with or without food. Taking it with food may help if your stomach gets upset. Always check the directions on your prescription label.  

Talk with your doctor or pharmacist if you have questions about how to take diltiazem.

How does diltiazem work? And how long does it take to start working?

Diltiazem works by relaxing your blood vessels. This lowers your blood pressure. It also lowers your heart rate, so the heart doesn’t pump as fast. These two actions reduce the workload on your heart. The heart doesn’t have to work as hard to pump blood through your body. When your heart doesn’t have to work as hard to function normally, you’re less likely to have chest pain.

How long it takes diltiazem to start working depends on the form you take. The injection given into the vein will start working right away. The oral forms of diltiazem will start working soon after you take them. But it can take up to 14 days to see the drug’s full effects.

If you’d like to know more about how diltiazem works, talk with your doctor or pharmacist.

Uses of diltiazem

The Food and Drug Administration (FDA) approves prescription drugs such as diltiazem for certain conditions. Approved uses for diltiazem are described below. These uses differ based on the form of diltiazem prescribed.

Use for high blood pressure

Doctors may prescribe diltiazem extended-release oral tablet and extended-release oral capsule for treating high blood pressure. They’re used for this purpose in adults. They’re usually prescribed as a long-term treatment.

With high blood pressure, you may not have any symptoms. But having high blood pressure puts you at risk of fatal and nonfatal heart and blood vessel problems. These include heart attack and stroke. Lowering blood pressure with diltiazem can help prevent these problems.

Diltiazem can be prescribed together with other blood-pressure-lowering medications.

Doctors may not prescribe diltiazem extended-release oral tablet or extended-release oral capsule in certain situations, such as for people with certain heart problems or very low blood pressure.

Use for angina

Doctors may prescribe diltiazem extended-release oral tablet, extended-release oral capsule, and oral tablet for treating angina (chest pain). They’re used for this purpose in adults. They’re usually prescribed as a long-term treatment.

With angina, you have reduced blood flow to the heart muscle. This causes the heart to beat harder or faster to try to get more blood. The result is pain because the heart is working too hard. Angina can feel like a squeezing pain, pressure, or tightness in the chest. Angina is a symptom of heart disease.

Doctors may not prescribe diltiazem extended-release oral tablet, extended-release oral capsule, or oral tablet in certain situations, such as for people with certain heart problems or very low blood pressure.

Use for heart rhythm problems

Doctors may prescribe diltiazem injection given into the vein for treating heart rhythm problems in a hospital setting. This form requires specialized monitoring and equipment. It’s used for this purpose in adults. It’s usually prescribed as a short-term treatment.

With heart rhythm problems, the heart beats at a rate or in a rhythm that isn’t normal. Diltiazem treats heart conditions where the heart beats much faster than usual. A rapid heartbeat can cause problems with blood circulation and lead to cardiac arrest.

Doctors may not prescribe diltiazem injection in certain situations, such as for people with certain heart problems or very low blood pressure.

Interactions and warnings for diltiazem

Below, you’ll find information about diltiazem’s possible interactions and warnings.

Interactions of diltiazem

Certain things may affect how a drug works. These include getting vaccines, consuming alcohol or certain foods, or taking the drug with other medications. This effect is called a drug interaction.

Before you take diltiazem, ask your doctor to check for possible interactions. Be sure to tell them about any of the following you take or use:

• prescription or over-the-counter drugs
• vitamins, herbs, or supplements

To learn about drug-condition interactions, see the “Warnings for diltiazem” section below.

Warnings for diltiazem

Some people should not take diltiazem, and others should take it cautiously.

Diltiazem could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether diltiazem is a safe option for you. These warnings may differ based on the form of diltiazem you take.

Ask your doctor about specific warnings for diltiazem, and be sure to tell your doctor about your:

• current health, including any allergies to medications
• past health conditions or surgeries

Allergic reaction

Diltiazem can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.

If you’ve had an allergic reaction to diltiazem or any of its ingredients, your doctor will likely not prescribe diltiazem. They can tell you about medications that are safer options for you.

A mild allergic reaction may cause the following symptoms:

• skin rash
• itchiness
• flushing (temporary warmth, redness, or deepening of skin color)

A severe allergic reaction may cause the following symptoms:

• severe skin rashes that may blister and peel
• swelling under your skin, usually in your hands, feet, eyelids, or lips
• swelling of your mouth, throat, or tongue, which can cause breathing problems

If you have an allergic reaction to diltiazem, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.

Overdose of diltiazem

If you take diltiazem by mouth, you should not take more diltiazem than your doctor prescribes. For some drugs, doing so may lead to harmful effects or overdose.

If you think you’ve taken too much diltiazem, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.

Pregnancy or breastfeeding and diltiazem

Information about diltiazem and pregnancy and breastfeeding is described below.

Diltiazem and pregnancy

It’s not known whether diltiazem should be taken during pregnancy. If you’re planning a pregnancy or can become pregnant, talk with your doctor before taking this medication.

Diltiazem and breastfeeding

Diltiazem should not be taken while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before taking this medication. Your doctor may recommend other ways to feed your child during treatment with diltiazem.

What to ask your doctor

Let your doctor know if you have questions about diltiazem or would like more details about it.

Here’s a list of some possible questions you may want to ask your doctor:

• Do any of my other medications interact with diltiazem?
• Am I at higher risk of side effects than other people?
• Are there any alternative medications that could treat my condition?

Resources

• Diltiazem hydrochloride capsule, extended release. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/839af3af-4040-4cf4-8d4a-881a053514cc/spl-doc
• Diltiazem hydrochloride injection, solution. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/f8d962ab-6cd4-43a1-a8fa-fb6548ac2a08/spl-doc
• Diltiazem hydrochloride tablet. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/225a87fb-d353-4ee7-bd08-14d631ff6b16/spl-doc
• Diltiazem hydrochloride tablet, extended release. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/bce61158-201d-458c-be0c-9bdd2d3a0bec/spl-doc  
• Food and Drug Administration. (2023). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.