Diltiazem (Oral)

Diltiazem is used for the treatment of hypertension or angina in patients. It can be used in isolation or in conjunction with other treatments for these conditions.


Diltiazem is an oral treatment used to treat angina or hypertension in patients.

High blood pressure is a very serious condition that adds to the workload of the heart and causes long-term and potentially life-threatening conditions if it is left untreated. When high blood pressure continues in a patient the patient may suffer from damage to the blood vessels in the heart, arteries, kidneys and brain. As a result the patient will be far more likely to suffer a heart attack, stroke or kidney failure. If blood pressure is controlled with medication such as Diltiazem then the risks are reduced and are less likely to occur.

This treatment is not a cure for angina or high blood pressure, however. This treatment lowers the blood pressure only temporarily. Diltiazem is a calcium channel blocker that prevents calcium from being transferred from the blood into the cells of the heart and into other blood vessels in the body. By blocking this transfer the blood vessels will relax and this allows a lowering of blood pressure. With a lowered blood pressure the body can more easily absorb oxygen and in doing so the workload on the cardiovascular system is reduced.

If the patient were to stop taking Diltiazem, however, then their blood pressure would immediately increase. This treatment will always be prescribed with diet and exercise advice that must be followed to help lower the blood pressure of the patient. Failing to lower blood pressure naturally will mean that the patient will need to take treatments to artificially lower their blood pressure for the rest of their lifetime and this can increase the risk of side effects and the severity of them.

This medication is only available when prescribed by a doctor and is available under the following brands:

  • Tiazac
  • Taztia XT
  • Matzim LA
  • Diltzac
  • Diltia XT
  • Dilt-XR
  • Dilt-CD
  • Dilacor XR
  • Cartia XT
  • Cardizem LA
  • Cardizem CD
  • Cardizem

The treatment is administered in a tablet form and is often prescribed as an extended release tablet or capsule to slow the release of the medication into the body.

These tablets must be taken on a strict schedule with proper diet and exercise management in order for them to be effective for the treatment of angina and high blood pressure.

Condition treated

  • Angina
  • High blood pressure

Type Of Medicine

  • Calcium channel blocker

Side Effects

In addition to the required effects of the use of Diltiazem, other side effects can also occur. Not all of the side effects listed may occur, but when they do the patient may need to seek medical attention.

You should check with your doctor immediately if you experience any of the following side effects from the use of Diltiazem:

Occurring more commonly:

  • Body aches
  • Body pains
  • Congestion
  • Coughing
  • Dryness of the throat
  • Feverishness
  • Hoarseness
  • Runny nose
  • Soreness of the throat
  • Tender and/or swollen glands in the neck
  • Trouble with swallowing
  • Voice pitch or tone changes

Occurring less commonly:

  • Chest discomfort
  • Chest pain
  • Chills when warm
  • Diarrhea
  • Difficulty with breathing
  • Feeling of faintness, dizziness or lightheadedness
  • Feeling of warmth or heat on skin
  • Flushed or red skin, especially on the face and neck
  • General feeling of discomfort and/or illness
  • Headaches
  • Irregular heartbeat
  • Joint pains
  • Labored breathing
  • Loss of hunger
  • Muscle aches
  • Muscle pains
  • Nausea
  • Shivering
  • Slow heartbeat
  • Sweating when cool
  • Swollen hands, ankles, feet or lower legs
  • Tightness across the chest
  • Trouble with sleeping
  • Unusual tiredness
  • Unusual weakness
  • Vomiting

Frequency of incidence unknown:

  • Blistering or peeling of the skin
  • Itching
  • Loosening of the skin
  • No heartbeat
  • Irritation and redness of the eyes
  • Red lesions that may often have a purple dot in the center
  • Sores and ulcers on the mouth
  • Swellings with the appearance of hives that appear on the eyelids, tongue, lips, throat, legs, feet, hands or sex organs
  • White spots appearing in the mouth or on the lips

Other side effects may also occur that would not normally require that you seek medical attention. These side effects do not normally indicate the presence of any other developing medical conditions and are usually mild. If they are extreme, however, or become bothersome and are ongoing then you can consult your doctor for advice on how best to alleviate the side effects:

Occurring more commonly:

  • Blocked nose
  • Sneezing

Occurring less commonly:

  • Acid stomach
  • Belching or burping
  • Constipation or difficulty in passing stools
  • Continued ringing or buzzing noise that is not heard by others
  • Degenerative diseases of the joints
  • Difficulty with movements
  • Hearing decline or loss
  • Heartburn
  • Indigestion
  • Lack of strength
  • Loss of strength
  • Muscle aching
  • Muscle cramping
  • Muscle pains
  • Muscle stiffness
  • Pain or tenderness occurring around the eyes and cheekbones
  • Rashes
  • Sour stomach
  • Stomach discomfort, upset or pains
  • Swelling of the joints

Frequency of incidence unknown:

Other side effects can also occur from the use of Diltiazem. If you experience other side effects not listed here then you should contact your doctor for advice on how to alleviate these side effects and whether you might need to seek medical attention. If you believe your health is at immediate risk, however, then you should always contact the emergency services.


In addition to the use of Diltiazem when treating patients with high blood pressure the doctor will also provide other advice on how to lower blood pressure. This will include weight control, changes to the foods that you eat, changes to the quantity of foods that you eat and the introduction of exercise to your regime. Your doctor will work with you to establish a healthy living plan that will help you to reduce your blood pressure. You should ensure that you follow this so you are able to naturally lower your blood pressure and can cease use of Diltiazem. Prolonged treatment with Diltiazem will expose you to greater risks of side effects so you should seek to improve your health so that you can discontinue use.

Many patients with high blood pressure can feel completely healthy and it is common for patients to believe that they no longer need the treatment. Stopping use without having lowered your blood pressure will expose you to significant risks once again, however. As this treatment is not a cure and instead is a temporary means with which to lower blood pressure, cessation of use will immediately expose you to high blood pressure and the risks associated with this once again. Cessation of use can result in heart failure, stroke, blood vessel disease and kidney disease.

If you are taking extended release capsules or tablets then they must be taken whole without being crushed, broken, dissolved or in any way changed.

The dose given will be different depending on the condition that you are taking it for and a range of other factors. You should only ever take this medication as directed to by your doctor and you should never take a different brand of this medication than that which you were prescribed. Do not make any changes to your dose unless directed to by your doctor. The following dosing information is a guideline only and changes should not be made to the treatment given based on this information:

When treating angina or chest pains:

With extended release capsules:

  • Adults: 120mg taken once daily in the morning. Dose may be adjusted by the doctor as required.
  • Children: Use of this treatment in children must be determined by the prescribing doctor.

With extended release tablets:

  • Adults: 180mg taken once daily in the morning or evening. Dose may be adjusted by the doctor as required.
  • Children: Use of this treatment in children must be determined by the prescribing doctor.

With tablets:

  • Adults: 30mg taken four times daily before each meal and before bed. Dose may be adjusted by the doctor as required.
  • Children: Use of this treatment in children must be determined by the prescribing doctor.

When treating high blood pressure:

With extended release capsules:

  • Adults: 180-240mg taken once daily in the morning. Dose may be adjusted by the doctor as required.
  • Children: Use of this treatment in children must be determined by the prescribing doctor.

With extended release tablets:

  • Adults: 180-240mg taken once daily in the morning or evening. Dose may be adjusted by the doctor as required.
  • Children: Use of this treatment in children must be determined by the prescribing doctor.

If you miss a dose of this medication then you should take it as soon as possible. If you are close to your next dose being due, however, then you should skip the missed dose completely and return to your normal dosing schedule. You should not take double doses of this treatment.

For effective use this treatment needs to be taken regularly and consistently. To ensure this is possible you should create a habit and take the medication at the same time and in the same way every day so that you are likely to remember to take it.


Certain medications should never be used in conjunction with one another. Doing so can put the patient at significant risk as medications can interact with one another in the body causing significant unwanted side effects. In some cases medications may stop one another from working or may expose the patient to more severe side effects caused by the other treatment. Before beginning treatment you should always inform your doctor of all treatments that you are taking including other prescription medications, over the counter treatments, vitamin supplements and even herbal remedies. All of these substances can react with Diltiazem in the body. Before you are prescribed with Diltiazem it is particularly important that you inform your doctor if you are taking any of the following treatments:

The use of Diltiazem with the following medications is not recommended. If you are taking one of these treatments then your doctor may choose to prescribe a different treatment or may decide to change one of the following treatments:

  • Lomitapide
  • Flibanserin
  • Colchicine
  • Cisapride

Using the following treatments in conjunction with Diltiazem is not normally recommended. On occasion a doctor may prescribe the use of both but in doing so may wish to make changes to the dose or frequency of use of one or more of the treatments:

  • Vincristine Sulfate Liposome
  • Vincristine
  • Venetoclax
  • Topotecan
  • Tolvaptan
  • Timolol
  • Tertatolol
  • Talinolol
  • Tacrolimus
  • St John's Wort
  • Sotalol
  • Sonidegib
  • Simvastatin
  • Simeprevir
  • Ranolazine
  • Propranolol
  • Pixantrone
  • Piperaquine
  • Pindolol
  • Penbutolol
  • Oxprenolol
  • Olaparib
  • Nilotinib
  • Nebivolol
  • Naloxegol
  • Nadolol
  • Morphine Sulfate Liposome
  • Morphine
  • Metoprolol
  • Metipranolol
  • Mepindolol
  • Lurasidone
  • Lovastatin
  • Levobunolol
  • Lacosamide
  • Labetalol
  • Ivacaftor
  • Ivabradine
  • Ifosfamide
  • Idelalisib
  • Ibrutinib
  • Hydrocodone
  • Fosaprepitant
  • Fingolimod
  • Fentanyl
  • Esmolol
  • Erythromycin
  • Eplerenone
  • Eliglustat
  • Droperidol
  • Dronedarone
  • Doxorubicin Hydrochloride Liposome
  • Doxorubicin
  • Domperidone
  • Dilevalol
  • Digoxin
  • Dantrolene
  • Cyclosporine
  • Crizotinib
  • Conivaptan
  • Cobimetinib
  • Clozapine
  • Clopidogrel
  • Clonidine
  • Clarithromycin
  • Cilostazol
  • Ceritinib
  • Celiprolol
  • Carvedilol
  • Carteolol
  • Carbamazepine
  • Bucindolol
  • Brexpiprazole
  • Bosutinib
  • Bisoprolol
  • Bevantolol
  • Betaxolol
  • Atorvastatin
  • Atenolol
  • Atazanavir
  • Aprepitant
  • Apixaban
  • Amiodarone
  • Alprenolol
  • Afatinib
  • Acebutolol

Using Diltiazem in conjunction with the following treatments can expose the patient to an increased risk of suffering certain side effects and is thus not normally recommended. The use of both may still be prescribed by your doctor but they may adjust the frequency of use or dose of one or more of the treatments:

  • Triazolam
  • Suvorexant
  • Sirolimus
  • Rifampin
  • Quinupristin
  • Phenytoin
  • Nevirapine
  • Moricizine
  • Midazolam
  • Methylprednisolone
  • Lithium
  • Indinavir
  • Guggul
  • Fosphenytoin
  • Enflurane
  • Efavirenz
  • Dutasteride
  • Digitoxin
  • Dalfopristin
  • Colestipol
  • Cimetidine
  • Buspirone
  • Alfuzosin
  • Alfentanil

Interactions between Diltiazem and other medications that have not been listed herein may also occur. The list herein was compiled in relation to the severity of interaction and is not necessarily all-inclusive. Ensure that you tell your doctor of all treatments you are receiving before beginning use of Diltiazem.

Medical conditions suffered by the patient other than the one being treated may also impact the safety and efficiency of use of Diltiazem. Some conditions may be worsened by the treatment and other conditions may make the treatment less effective. You should disclose your full medical history to your doctor before use of this treatment. This is especially important if you suffer or have suffered from the following conditions:

Other medical conditions may also impact use. Inform your doctor of all conditions from which you suffer.


Before beginning use of Diltiazem you should understand the risks of use and the benefits of use. Discuss these with your doctor to make the decision.

You should inform your doctor of any allergies from which you have suffered in the past before beginning treatment.

If you are pregnant or may become pregnant during use then you should inform your doctor. This medication will expose the fetus to risk and should be avoided where possible. Other alternative medications or treatments may be available for pregnant women.

During use you must visit your doctor regularly so that they can determine if it is effective and check that no unwanted side effects are occurring.

Hypotension can occur from the use of this treatment. Patients should contact their doctor immediately if the following symptoms of hypotension occur:

  • Confusion
  • Blurring of vision
  • Severe dizziness
  • Faintness
  • Unusual weakness
  • Unusual tiredness

Patients may develop serious skin conditions during use of this treatment. If you notice any changes to your skin then you should contact your doctor immediately for treatment.

Prolonged use of this treatment will increase your risk of suffering serious side effects. Patients should seek to lower their blood pressure naturally to reduce this risk.


You should store this medication at room temperature. Ensure that it is always kept out of direct light and away from both moisture and heat. You should keep this treatment from freezing.

Always keep this medication out of the reach of children.

Ensure that any outdated or unwanted medication is disposed of properly and safely as directed by your doctor.


Diltiazem is a treatment used in patients suffering from angina or hypertension. The medication is a calcium channel blocker that prevents calcium from passing into the cells of the heart and into blood vessels. In doing so this causes the blood vessels to relax and this lowers the blood pressure. With a lower blood pressure, more oxygen can be transferred around the body and the strain placed on the heart can be reduced.

In patients being treated for high blood pressure this treatment will be given in conjunction with advice on healthy eating, exercise and weight loss. This treatment does not cure high blood pressure and the patient will need to take it for their entire lifetime if they are unable to lower their blood pressure naturally through following a healthier lifestyle. Prolonged use of this medication can increase the risk of suffering significant side effects so patients should take every step they can to lower their blood pressure and enable their body to cope without the use of this treatment.

This medication is available with a prescription only and is taken in tablet form. It must be taken regularly on a schedule so that it can have the desired effect on the patient's health.