Diltiazem, Oral Capsule

• Liver problems warning: 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. Your doctor may check your liver function. They’ll decide if you should keep taking this drug.
• Low blood pressure warning: This drug can cause low blood pressure and symptoms such as dizziness.
• Low heart rate warning: This drug may lower your heart rate, especially if you have certain types of heart conditions that already cause low heart rate.

Diltiazem oral capsule is a prescription drug that’s available as the brand-name drugs Cardizem CD and Taztia XT. Diltiazem oral tablet is available as the brand-name drug Cardizem. The extended-release form of diltiazem oral capsule is also 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.

Diltiazem is available as an extended-release capsule. It is also available as an immediate-release tablet, an extended-release tablet, and an intravenous (IV) solution, which is only given by a healthcare professional.

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. 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.

Diltiazem oral capsule doesn’t cause drowsiness. However, it can cause other side effects.

More common side effects

The more 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 with your doctor or pharmacist.

Serious side effects

If you experience any 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 911. Serious side effects include:

• 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

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 professional who knows your medical history.

Diltiazem oral capsule can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk with your doctor or pharmacist.

Examples of drugs that can cause interactions with diltiazem are listed below.

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 professional about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

Diltiazem oral capsule comes with several warnings.

Allergy warning

Diltiazem can cause a severe allergic reaction. Symptoms include:

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

Call 911 or go to the nearest emergency room if you develop these symptoms.

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

Alcohol interaction

Drinking alcohol while you take diltiazem can increase the amount of diltiazem in your body. Don’t have drinks that contain alcohol while taking this drug.

Warnings for people with certain health conditions

For 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.

For 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.

For 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. If you have heart failure, your symptoms may get worse if you use this drug, especially if you also use beta-blockers. If you have heart failure, tell your doctor.

Warnings for other groups

For pregnant people: Research in animals has shown adverse effects to the fetus when the mother takes the drug. There haven’t been enough studies done in humans to be certain how the drug might affect the pregnancy, however. 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.

For people who are breastfeeding: Diltiazem may pass into breast milk and may cause side effects in a child who is breastfed. Talk with your doctor if you breastfeed your baby. You may need to decide whether to stop breastfeeding or stop taking this medication.

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

This dosage information is for diltiazem oral capsules and oral tablets. 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

Forms and strengths

Brand: Cardizem

• Form: Oral immediate-release tablet
• Strengths: 30 mg, 60 mg, 90 mg, 120 mg

Brand: Cardizem CD

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

Brand: Cardizem LA

• Form: Oral extended-release tablet
• 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

Dosage for hypertension

Adult dosage (ages 18 to 64 years)

• Extended-release tablets: The standard starting dosage is 180–240 mg taken by mouth once per day. Your doctor may slowly increase your dosage to 240–540 mg taken once per day.
• Extended-release capsules: The standard starting dosage is 180–240 mg taken by mouth once per day. Your doctor may increase your dosage to 240–480 mg taken once per day.

Child dosage (ages 0 to 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.

Dosage for angina

Adult dosage (ages 18 to 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 to 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 to 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 speak with your doctor or pharmacist about dosages that are right for you.

Diltiazem oral capsule is used for long-term treatment. It comes with 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 talking 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, your 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.

Keep these considerations in mind if your doctor prescribes diltiazem oral capsules for you.

General

• Diltiazem can be taken with or without food.
• 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.

Storage

Store diltiazem at 59°F to 86°F (15°C to 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.

Refills

A prescription for this medication is refillable. You shouldn’t need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

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.

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

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 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.