Generic Name: Diltiazem Brand Name(s): Generics only. No brands available.

Know the basics

What is diltiazem used for?

Diltiazem is used to treat high blood pressure (hypertension) and prevent chest pain (angina). Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. When used regularly, diltiazem can decrease the number and severity of episodes of chest pain from angina. It may help increase your ability to exercise.

Diltiazem is called a calcium channel blocker. It works by relaxing blood vessels in the body and heart so blood can flow more easily. Diltiazem also lowers your heart rate. These effects help the heart work less hard and lower blood pressure.

OTHER USES: This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by yourhealth care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

Diltiazem may also be used to control your heart rate if you have a fast/irregular heartbeat (such as atrial fibrillation).

How should I take diltiazem?

Take diltiazem by mouth with or without food, usually once daily or as directed by your doctor. Swallow the capsules whole. Do not crush or chew the capsules. Doing so can release all of the drug at once and may increase your risk of side effects.

If you have trouble swallowing the capsule, you may open the capsule and carefully sprinkle its contents on a spoonful of soft, cool applesauce just before you take it. Swallow all of the drug/food mixture immediately. Do not chew the mixture. Then rinse your mouth and swallow the rinse liquid to make sure that you have swallowed all of the medicine. Do not prepare a supply in advance.

Your doctor may gradually increase your dose. Follow your doctor’s instructions carefully. Dosage is based on your medical condition and response to treatment.

Use diltiazem regularly to get the most benefit from it. To help you remember, use it at the same time each day. It is important to continue taking diltiazem even if you feel well. Most people with high blood pressure do not feel sick. For the treatment of high blood pressure, it may take 2 to 4 weeks before you get the full benefit of this drug.

Diltiazem must be taken regularly to prevent angina. It should not be used to treat angina when it occurs. Use other medications (such as nitroglycerin placed under the tongue) to relieve an angina attack as directed by your doctor. Consult your doctor or pharmacist for details.

Tell your doctor if your condition worsens (for example, your chest pain worsens or your routine blood pressure readings increase).

How do I store diltiazem?

Diltiazem is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store diltiazem in the bathroom or the freezer. There may be different brands of diltiazem that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush diltiazem down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Know the precautions & warnings

What should I know before using diltiazem?

Before taking diltiazem,

  • tell your doctor and pharmacist if you are allergic to diltiazem, any other medications, or any of the ingredients in diltiazem. Ask your pharmacist for a list of the ingredients.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: atazanavir (Reyataz); benzodiazepines such as midazolam (Versed) and triazolam (Halcion); beta blockers such as atenolol (Tenormin), labetalol (Trandate), metoprolol (Lopressor, Toprol XL), nadolol (Corgard), and propranolol (Inderal); buspirone (BuSpar); carbamazepine (Carbatrol, Epitol, Tegretol); cimetidine (Tagamet); cyclosporine (Gengraf, Neoral, Sandimmune); digoxin (Lanoxin, Lanoxicaps); lovastatin (Altoprev, Mevacor, in Advicor); quinidine (Quinidex); and rifampin (Rifadin, in Rifamate, in Rifater, Rimactane). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with diltiazem, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
  • tell your doctor if you have or have ever had a myocardial infarction (MI); a narrowing or blockage of your digestive system or any other condition that causes food to move through your digestive system more slowly; low blood pressure; or heart, liver, or kidney disease.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking diltiazem, call your doctor.
  • if you are having surgery, including dental surgery, tell your doctor or dentist that you are taking diltiazem.

Is it safe to take diltiazem during pregnancy or breast-feeding?

There are no adequate studies in women for determining risk when using this medication during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking this medication. This medication is pregnancy risk category C according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk,
  • B=No risk in some studies,
  • C=There may be some risk,
  • D=Positive evidence of risk,
  • X=Contraindicated,
  • N=Unknown.

Know the side effects

What are the side effects of diltiazem?

Common side effects include dizziness, lightheadedness, weakness, nausea, flushing, and headache.

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have a serious side effect such as:

  • a red, blistering skin rash;
  • swelling in your hands or feet;
  • trouble breathing;
  • slow heartbeats;
  • dizziness, fainting, fast or pounding heartbeat;
  • upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
  • severe skin reaction — fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Less serious side effects may include:

  • headache;
  • dizziness, weakness, tired feeling;
  • upset stomach, nausea;
  • sore throat, cough, stuffy nose;
  • flushing (warmth, redness, or tingly feeling).

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.

Know the interactions

What drugs may interact with diltiazem?

Diltiazem may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Cisapride, Colchicine, Lomitapide.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Acebutolol, Afatinib, Alprenolol, Amiodarone, Aprepitant, Atazanavir, Atenolol, Atorvastatin, Betaxolol, Bevantolol, Bisoprolol, Bosutinib, Bucindolol, Carbamazepine, Carteolol, Carvedilol, Celiprolol, Ceritinib, Clarithromycin, Clonidine, Clopidogrel, Clozapine, Crizotinib, Dabigatran Etexilate, Dantrolene, Dilevalol, Domperidone, Doxorubicin, Doxorubicin Hydrochloride Liposome, Dronedarone, Droperidol, Eliglustat, Erythromycin, Esmolol, Everolimus, Fentanyl, Fingolimod, Hydrocodone, Ibrutinib, Idelalisib, Ifosfamide, Ivabradine, Labetalol, Lacosamide, Levobunolol, Lovastatin, Lurasidone, Mepindolol, Metipranolol, Metoprolol, Morphine, Morphine Sulfate Liposome, Nadolol, Nebivolol, Nilotinib, Nintedanib, Oxprenolol, Penbutolol, Pindolol, Piperaquine, Pixantrone, Pomalidomide, Propranolol, Ranolazine, Romidepsin, Siltuximab, Simeprevir, Simvastatin, Sotalol, St John’s Wort, Talinolol, Tertatolol, Timolol, Tolvaptan, Topotecan, Trabectedin, Vilazodone, Vincristine, Vincristine Sulfate Liposome.

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Aceclofenac, Acemetacin, Alfentanil, Alfuzosin, Amlodipine, Amtolmetin Guacil, Aspirin, Bromfenac, Bufexamac, Buspirone, Celecoxib, Choline Salicylate, Cilostazol, Cimetidine, Clonixin, Colestipol, Cyclosporine, Dalfopristin, Dexibuprofen, Dexketoprofen, Diclofenac, Diflunisal, Digitoxin, Digoxin, Dipyrone, Dutasteride, Efavirenz, Enflurane, Etodolac, Etofenamate, Etoricoxib, Felbinac, Fenoprofen, Fepradinol, Feprazone, Floctafenine, Flufenamic Acid, Flurbiprofen, Fosaprepitant, Fosphenytoin, Guggul, Ibuprofen, Ibuprofen Lysine, Indinavir, Indomethacin, Ketoprofen, Ketorolac, Lithium, Lornoxicam, Loxoprofen, Lumiracoxib, Meclofenamate, Mefenamic Acid, Meloxicam, Methylprednisolone, Midazolam, Moricizine, Morniflumate, Nabumetone, Naproxen, Nepafenac, Nevirapine, Nifedipine, Niflumic Acid, Nimesulide, Oxaprozin, Oxyphenbutazone, Parecoxib, Phenylbutazone, Phenytoin, Piketoprofen, Piroxicam, Pranoprofen, Proglumetacin, Propyphenazone, Proquazone, Quinupristin, Rifampin, Rifapentine, Ritonavir, Rofecoxib, Salicylic Acid, Salsalate, Sirolimus, Sodium Salicylate, Sulindac, Tacrolimus, Tenoxicam, Tiaprofenic Acid, Tolfenamic Acid, Tolmetin, Triazolam, Valdecoxib.

Does food or alcohol interact with diltiazem?

Diltiazem may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with diltiazem?

Diltiazem may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have, especially:

  • Bowel blockage, severe;
  • Congestive heart failure—Use with caution. May make this condition worse.
  • Heart attack;
  • Heart block (type of abnormal heart rhythm, can use if have a pacemaker that works properly);
  • Hypotension (low blood pressure), severe;
  • Lung problem (e.g., pulmonary congestion);
  • Sick sinus syndrome (type of abnormal heart rhythm, can use if have a pacemaker that works properly)—Should not be used in patients with these conditions .
  • Kidney disease;
  • Liver disease—Use with caution. The effects of this medicine may be increased because of slower removal from the body

Understand the Dosage

The information provided is not a substitute for medical advice. ALWAYS consult your doctor or pharmacist before using this medication.

What is the dose of Diltiazem for an adult?

Usual Adult Dose for Hypertension

Initial dose: 30 to 60 mg orally 3 to 4 times a day.
Maintenance dose: 180 to 360 mg orally/day in divided doses.
SR initial dose: 60 to 120 mg orally twice a day.
SR maintenance dose: 240 to 360 mg orally/day.
CD or XR initial dose: 120 to 240 mg orally once a day.
CD maintenance dose: 240 to 360 mg orally once a day.
XR maintenance dose: 240 to 480 mg orally once a day.
LA initial dose: 120 to 240 mg orally once a day.
LA maintenance dose: 240 to 420 mg orally once a day.

Intravenous Dosing:
Initial bolus doses: 0.25 mg/kg as a bolus administered over 2 minutes. A second bolus of 0.35 mg/kg may be used if necessary.
Initial infusion dose: 5 mg/hr.
Maintenance infusion dose: The infusion rate may be increased in 5 mg/hr increments up to 15 mg/hr.

Usual Adult Dose for Atrial Fibrillation

Initial dose (oral): 30 to 60 mg orally 3 to 4 times a day
Maintenance dose: 180 to 360 mg orally/day in divided doses.
SR initial dose: 60 to 120 mg orally twice a day
SR maintenance dose: 240 to 360 mg orally/day.
CD or XR initial dose: 120 to 240 mg orally once a day.
CD maintenance dose: 240 to 360 mg orally once a day.
LA initial dose: 120 to 240 mg orally once a day.
LA maintenance dose: 240 to 420 mg orally once a day.

Initial dose (Intravenous): 0.25 mg/kg actual body weight bolus over 2 minutes. If necessary, a second bolus of 0.35 mg/kg ABW may be given. In some cases, an infusion of diltiazem 5 mg/hour may be started, and advanced in 5 mg/hour increments to 15 mg/hour for up to 24 hours.

Usual Adult Dose for Atrial Flutter

Initial dose (oral): 30 to 60 mg orally 3 to 4 times a day
Maintenance dose: 180 to 360 mg orally/day in divided doses.
SR initial dose: 60 to 120 mg orally twice a day
SR maintenance dose: 240 to 360 mg orally/day.
CD or XR initial dose: 120 to 240 mg orally once a day.
CD maintenance dose: 240 to 360 mg orally once a day.
LA initial dose: 120 to 240 mg orally once a day.
LA maintenance dose: 240 to 420 mg orally once a day.

Initial dose (Intravenous): 0.25 mg/kg actual body weight bolus over 2 minutes. If necessary, a second bolus of 0.35 mg/kg ABW may be given. In some cases, an infusion of diltiazem 5 mg/hour may be started, and advanced in 5 mg/hour increments to 15 mg/hour for up to 24 hours.

Usual Adult Dose for Supraventricular Tachycardia

Initial dose (oral): 30 to 60 mg orally 3 to 4 times a day
Maintenance dose: 180 to 360 mg orally/day in divided doses.
SR initial dose: 60 to 120 mg orally twice a day
SR maintenance dose: 240 to 360 mg orally/day.
CD or XR initial dose: 120 to 240 mg orally once a day.
CD maintenance dose: 240 to 360 mg orally once a day.
LA initial dose: 120 to 240 mg orally once a day.
LA maintenance dose: 240 to 420 mg orally once a day.

Initial dose (Intravenous): 0.25 mg/kg actual body weight bolus over 2 minutes. If necessary, a second bolus of 0.35 mg/kg ABW may be given. In some cases, an infusion of diltiazem 5 mg/hour may be started, and advanced in 5 mg/hour increments to 15 mg/hour for up to 24 hours.

Usual Adult Dose for Angina Pectoris Prophylaxis

Initial dose: 30 to 60 mg orally 3 to 4 times a day
Maintenance dose: 180 to 360 mg orally/day in divided doses.
SR initial dose: 60 to 120 mg orally twice a day
SR maintenance dose: 240 to 360 mg orally/day.
CD or XR initial dose: 120 to 240 mg orally once a day.
CD maintenance dose: 240 to 360 mg orally once a day.
LA initial dose: 120 to 240 mg orally once a day.
LA maintenance dose: 240 to 360 mg orally once a day.

Usual Adult Dose for Congestive Heart Failure

Initial dose: 30 to 60 mg orally 3 to 4 times a day
Maintenance dose: 180 to 360 mg orally/day in divided doses.
SR initial dose: 60 to 120 mg orally twice a day
SR maintenance dose: 240 to 360 mg orally/day.
CD or XR initial dose: 120 to 240 mg orally once a day.
CD maintenance dose: 240 to 360 mg orally once a day.
LA initial dose: 120 to 240 mg orally once a day.
LA maintenance dose: 240 to 360 mg orally once a day.

What is the dose of Diltiazem for a child?

The dosage has not been established in pediatric patients. It may be unsafe for your child. It is always important to fully understand the safety of the drug before using. Please consult with your doctor or pharmacist for more information.

How is diltiazem available?

Diltiazem is available in the following dosage forms and strengths:

Capsule Extended Release 12 Hour, Oral, as hydrochloride:

Generic: 60 mg, 90 mg, 120 mg

Capsule Extended Release 24 Hour, Oral, as hydrochloride:

Cardizem CD: 120 mg, 180 mg, 240 mg, 300 mg, 360 mg

Cartia XT: 120 mg, 180 mg, 240 mg, 300 mg

Dilacor XR: 240 mg

Dilt-CD: 120 mg

Dilt-CD: 180 mg, 240 mg

Dilt-CD: 300 mg

Dilt-XR: 120 mg, 180 mg, 240 mg

Diltiazem HCL CD: 360 mg

Diltzac: 120 mg, 180 mg, 240 mg, 300 mg, 360 mg

Taztia XT: 120 mg, 180 mg, 240 mg, 300 mg, 360 mg

Tiazac: 120 mg, 180 mg, 240 mg, 300 mg, 360 mg, 420 mg

Generic: 120 mg, 180 mg, 240 mg, 300 mg, 360 mg, 420 mg

Solution, Intravenous, as hydrochloride:

Generic: 25 mg/5 mL (5 mL); 50 mg/10 mL (10 mL), 125 mg/25 mL (25 mL)

Solution, Intravenous, as hydrochloride [preservative free]:

Generic: 25 mg/5 mL (5 mL); 50 mg/10 mL (10 mL), 125 mg/25 mL (25 mL)

Solution Reconstituted, Intravenous, as hydrochloride:

Generic: 100 mg

Tablet, Oral, as hydrochloride:

Cardizem: 30 mg, 60 mg, 90 mg, 120 mg

Generic: 30 mg, 60 mg, 90 mg, 120 mg

Tablet Extended Release 24 Hour, Oral, as hydrochloride:

Cardizem LA: 120 mg, 180 mg, 240 mg, 300 mg, 360 mg, 420 mg

Matzim LA: 120 mg, 180 mg, 240 mg, 300 mg, 360 mg, 420 mg

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

Symptoms of overdose may include:

  • Slow, fast, or irregular heartbeat;
  • Fainting;
  • Difficulty breathing;
  • Seizures;
  • Dizziness;
  • Confusion;
  • Nausea;
  • Vomiting;
  • Increased sweating.

What should I do if I miss a dose?

If you miss a dose of diltiazem, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: January 4, 2017 | Last Modified: January 4, 2017

Want to live your best life?
Get the Hello Doktor Daily newsletter for health tips, wellness updates and more.