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Generic Name:

diltiazem, Oral capsule

All Brands

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Highlights for diltiazem

Oral capsule
1

Diltiazem is a prescription drug that’s used to treat angina (chest pain) and hypertension (high blood pressure).

2

Diltiazem is available as an immediate-release tablet, extended-release tablet, and extended-release capsule. It’s also available as an intravenous (IV) solution, which is only given by a healthcare provider (the IV form is used to treat different conditions).

3

The usual dose of immediate-release diltiazem for adults with chest pain is 30 mg taken by mouth four times per day (this form isn’t approved for adults with high blood pressure). The standard starting dose for adults taking diltiazem extended-release for chest pain is 120–180 mg taken once per day. For high blood pressure, the starting dose of the extended-release form of the drug is 120–240 mg taken once per day. Your doctor may increase your dose.

4

You shouldn’t use this drug if you have certain problems. These include poor heart function, low blood pressure, sensitivity to the drug, heart attack, or fluid buildup in your lungs.

5

Common side effects include swelling, headache, nausea, dizziness, skin rash, and weakness.

IMPORTANT INFORMATION

Liver problems

This drug can cause mild increases in your liver function enzymes. In rare cases, it may cause sudden harm to your liver. This liver damage often goes away when you stop taking the medication. You doctor may check your liver function. They’ll decide if you should keep taking this drug.

What is diltiazem?

Diltiazem is a prescription drug. It’s available in these forms: immediate-release tablet, extended-release tablet, extended-release capsule, and intravenous (IV), which is only given by a healthcare provider.

Diltiazem is available as a generic drug. Generic drugs usually cost less. In some cases they may not be available in every strength or form as the brand. Talk to your healthcare provider to see if the generic will work for you.

Why it's used

Diltiazem is used to treat chest pain and high blood pressure.

How it works

Diltiazem belongs to a class of drugs called calcium channel blockers.

More Details

How it works

Diltiazem belongs to a class of drugs called calcium channel blockers. A class of drugs refers to medications that work similarly. They have a similar chemical structure and are often used to treat similar conditions.

Diltiazem works by relaxing the blood vessels in your heart and body. This reduces your blood pressure.

This drug also lowers your heart rate and dilates your coronary arteries. This means that your heart doesn’t have to work as hard to pump blood throughout your body. These effects, combined with lowering your blood pressure, help to reduce your chest pain.

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diltiazem Side Effects

Oral capsule

More Common Side Effects

The most common side effects that occur with diltiazem include:

  • headache

  • dizziness

  • slow heart beat

  • fluid buildup or swelling

  • weakness

  • nausea

  • rash

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious Side Effects

If you experience any of these serious side effects, call your doctor right away. If your symptoms are potentially life threatening or if you think you’re experiencing a medical emergency, call 9-1-1.

  • heart problems. Symptoms include:

    • slower than normal heart rate
    • worsening chest pain
  • liver problems. Symptoms include:

    • yellowing of your skin or the whites of your eyes
    • dark-colored urine
    • upper stomach pain
  • skin problems. Symptoms include:

    • swelling in face or tongue
    • red or purple rash that spreads on your skin
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

Diltiazem doesn’t cause drowsiness.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
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diltiazem May Interact with Other Medications

Oral capsule

Diltiazem can interact with other medications, herbs, or vitamins you might be taking. That’s why your doctor should manage all of your medications carefully. If you’re curious about how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Note: You can reduce your chances of drug interactions by having all of your prescriptions filled at the same pharmacy. That way, a pharmacist can check for possible drug interactions.

Medications that might interact with this drug

Antibiotics

Taking these drugs together can decrease the amount of diltiazem in your body. This means that it won’t work as well to treat your high blood pressure or chest pain.

These drugs include:

  • rifampin

Anxiety drugs

Diltiazem can increase the amount of these medications in your body. This can cause more side effects:

These drugs include:

  • benzodiazepines, such as:
    • midazolam
    • triazolam
  • buspirone

Cholesterol drugs

Diltiazem can increase the amount of these medications in your body. This can cause more side effects:

These drugs include:

  • simvastatin
  • atorvastatin

Heart drugs

Diltiazem can increase the levels of certain heart drugs in your body. This means that you may have more side effects.

These drugs include:

  • propranolol
  • digoxin (digitalis)
  • quinidine

Taking diltiazem could cause a slow heartbeat (bradycardia) when taken with certain heart drugs.

These drugs include:

  • beta-blockers, such as:
    • metoprolol
    • propranolol

Immune system suppressing drugs

Diltiazem can increase the amount of these medications in your body. This can cause more side effects:

These drugs include:

  • cyclosporine

Seizure drugs

Diltiazem can increase the amount of these medications in your body. This can cause more side effects:

These drugs include:

  • carbamazepine

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
Diltiazem warnings
recent heart attack
People who have had a recent heart attack

If you’ve had a recent heart attack and have fluid buildup in your lungs, you shouldn’t take this drug. Diltiazem could worsen your condition by slowing down your heart.

liver disease
People with liver disease

Diltiazem may cause more harm to your liver. Your doctor may monitor your liver function while you’re on this drug.

heart problems
People with certain heart problems

You shouldn’t use diltiazem if you have sick sinus syndrome or atrioventricular (AV) block unless you have a pacemaker. This drug can rarely cause a very slow heart rate. Your risk for this may be higher if you take other heart medications called beta-blockers or digoxin.

pregnant women
Pregnant women

Diltiazem is a category C pregnancy drug. That means two things:

  1. Research in animals has shown adverse effects to the fetus when the mother takes the drug.
  2. There haven’t been enough studies done in humans to be certain how the drug might affect the fetus.

Tell your doctor if you’re pregnant or plan to become pregnant. Diltiazem should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

breast-feeding
Women who are breast-feeding

Diltiazem may pass into breast milk and may cause side effects in a child who is breast-fed.

Talk to your doctor if you breast-feed your baby. You may need to decide whether to stop breast-feeding or stop taking this medication.

for seniors
For seniors

Older adults may process drugs more slowly. A normal adult dose may cause levels of this drug to be higher than normal. If you’re a senior, you may need a lower dose or a different schedule.

for children
For children

This medicine hasn’t been studied in children and shouldn’t be used in children under the age of 18 years.

allergies
Allergies

Diltiazem can cause a severe allergic reaction. Symptoms include:

  • rash
  • fever
  • trouble breathing
  • facial swelling (edema)

Call 9-1-1 or go to the nearest emergency room if you develop these symptoms.

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).

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How to Take diltiazem (Dosage)

Oral capsule

All possible dosages and forms may not be included here. Your dose, form, and how often you take it will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What are you taking this medication for?

Hypertension

Brand: Cardizem

Form: Oral immediate-release tablet
Strengths: 30 mg, 60 mg, 120 mg

Brand: Cardizem CD

Form: Oral immediate-release capsule
Strengths: 120 mg, 180 mg, 240 mg, 300 mg, 360 mg

Brand: Cardizem LA

Form: Oral extended-release capsule
Strengths: 120 mg, 180 mg, 240 mg, 300 mg, 360 mg, 420 mg

Generic: diltiazem

Form: Oral extended-release capsule
Strengths: 60 mg, 90 mg, 120 mg, 180 mg, 240 mg, 300 mg, 360 mg, 420 mg
Form: Oral extended-release tablet
Strengths: 120 mg, 180 mg, 240 mg, 300 mg, 360 mg, 420 mg
Form: Oral immediate-release tablet
Strengths: 30 mg, 60 mg, 90 mg, 120 mg
Adult dosage (ages 18–64 years)
  • Immediate-release tablets: The standard starting dose is 30 mg taken by mouth 4 times per day. Your doctor may slowly increase your dose to 180–360 mg per day taken in 3–4 divided doses.
  • Extended-release capsules and tablets: The standard starting dose is 120–240 mg taken by mouth once per day. Your doctor may increase your dose to 240–540 mg taken once per day.
Child dosage (ages 0–17 years)

This medicine hasn’t been studied in children and shouldn’t be used in children under the age of 18 years.

Senior dosage (ages 65 years and older)

There are no specific recommendations for senior dosing. Older adults may process drugs more slowly. A normal adult dose may cause levels of this drug to be higher than normal in your body. If you’re a senior, you may need a lower dose or a different schedule.

Angina

Brand: Cardizem

Form: Oral immediate-release tablet
Strengths: 30 mg, 60 mg, 120 mg

Brand: Cardizem CD

Form: Oral immediate-release capsule
Strengths: 120 mg, 180 mg, 240 mg, 300 mg, 360 mg

Brand: Cardizem LA

Form: Oral extended-release capsule
Strengths: 120 mg, 180 mg, 240 mg, 300 mg, 360 mg, 420 mg

Generic: diltiazem

Form: Oral extended-release capsule
Strengths: 60 mg, 90 mg, 120 mg, 180 mg, 240 mg, 300 mg, 360 mg, 420 mg
Form: Oral extended-release tablet
Strengths: 120 mg, 180 mg, 240 mg, 300 mg, 360 mg, 420 mg
Form: Oral immediate-release tablet
Strengths: 30 mg, 60 mg, 90 mg, 120 mg
Adult dosage (ages 18–64 years)
  • Immediate-release tablets: The standard starting dose is 30 mg taken by mouth 4 times per day. Your doctor may slowly increase your dose to 180–360 mg per day taken in 3–4 divided doses.
  • Extended-release capsules: The standard starting dose is 120–180 mg taken by mouth once per day. Your doctor may increase your dose to 480 mg taken once per day.
  • Extended-release tablets: The standard starting dose is 180 mg taken by mouth once per day. Your doctor may increase your dose to 360 mg taken once per day.
Child dosage (ages 0–17 years)

This medicine hasn’t been studied in children and shouldn’t be used in children under the age of 18 years.

Senior dosage (ages 65 years and older)

There are no specific recommendations for senior dosing. Older adults may process drugs more slowly. A normal adult dose may cause levels of this drug to be higher than normal in your body. If you’re a senior, you may need a lower dose or a different schedule.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

Diltiazem comes with serious risks if you don't take it as prescribed.

If you don't take it at all

If you don’t take diltiazem, your blood pressure and chest pain could get worse. This can lead to a heart attack or stroke.

If you stop taking it suddenly

Don’t stop taking diltiazem without taking to your doctor. Your blood pressure can become higher if you stop taking this drug suddenly. This can raise your chance for a heart attack or stroke.

If you don't take it on schedule

If you don’t take diltiazem on schedule, you blood pressure may get worse or not improve. This can increase your risk for a stroke or heart attack. Take your medication at the same time every day.

If you take too much

You could have dangerous levels of the drug in your body. If you take too much, you may have the following symptoms:

  • low blood pressure
  • very slow heartbeat

If you think you’ve taken too much of the drug, act right away. Call your doctor or local Poison Control Center, or go to the nearest emergency room. 

What to do if you miss a dose

If you forget to take your dose, take it as soon as you remember. If it’s just a few hours until the time for your next dose, then wait and only take one dose at that time.

Never try to catch up by taking two doses at once. This could cause toxic side effects.

How to tell if the drug is working

If diltiazem is working for you, your blood pressure will be lower and your chest pain will improve.

Diltiazem is used for long-term treatment.

You can cut immediate-release tablets

The immediate-release tablets may be split along the line down the center (score line).

Don’t crush, chew, or break extended-release tablets or capsules.

Store diltiazem at room temperature

Keep it from 59–86°F (15–30°C).

Keep this drug away from light and high temperature.

Keep your drugs away from areas where they could get wet, such as bathrooms. Store this drug away from moisture and damp locations.

Travel

When traveling with your medication:

  • Always carry your medication with you, such as in your carry-on bag.
  • Don’t worry about airport X-ray machines. They can’t hurt your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled box with you.
  • Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Self-management

You may need to check your blood pressure and heart rate at home. You should keep a log with the date, time of day, and your blood pressure readings. Bring this diary with you to your doctor appointments.

You may need to buy your own blood pressure monitoring machine. These are available at most pharmacies.

Clinical monitoring

While you’re taking diltiazem, your doctor will monitor your:

  • heart rate
  • blood pressure
  • kidney function
  • liver function

Hidden costs

You may need to purchase a blood pressure monitor to check your heart rate and blood pressure at home.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be more suitable for you than others. Talk to your doctor about possible alternatives.

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How Much Does diltiazem Cost?

Oral capsule

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Lowest price for diltiazem

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These prices represent the lowest priced national pharmacies for diltiazem on GoodRx. They may be lower than your insurance.

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These prices represent the lowest priced national pharmacies for diltiazem on GoodRx. They may be lower than your insurance.

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Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on September 17, 2015

Disclaimer: Healthline 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 other 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.
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