Diltiazem vs. Metoprolol for Atrial Fibrillation: 4 Differences to Know
Diltiazem (Cardizem) and metoprolol are both approved to treat atrial fibrillation. Compare differences in how they work, side effects, and more.
cartia XT
Used for Angina, Hypertension
Used for Angina, Hypertension
Diltiazem extended-release (ER) is a calcium channel blocker. It's used to treat high blood pressure and chest pain (or angina) in adults. There are several brand names of diltiazem ER (e.g., Cardizem CD, Cartia XT, Tiazac), but they're not all interchangeable with each other. Diltiazem ER is taken by mouth, typically once or twice daily, depending on which brand or generic you're prescribed. Some side effects of this medication include headache, dizziness, and constipation.
What is Diltiazem ER?
What is Diltiazem ER used for?
- High blood pressure
- Chest pain
How Diltiazem ER works
Diltiazem ER is a calcium channel blocker. It works by slowing your heart rate and relaxing your blood vessels to lower your blood pressure. This also helps your heart to get more oxygen so it doesn't need to work as hard to pump, which can help with chest pain.
When does Diltiazem ER start working?Time passed since treatment started:
Drug facts
| Common Brands | Cardizem CD, Cardizem LA, Cartia XT, Tiazac, Taztia XT |
|---|---|
| Drug Class | Calcium channel blocker (CCB) |
| Controlled Substance Classification | Not a controlled medication |
| Generic Status | Lower-cost generic available |
| Availability | Prescription only |
More on Diltiazem ER essentials
Side effects of Diltiazem ER
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
Cardizem CD and Cartia XT:
- Headache (5%)
- Dizziness (3%)
- Low heart rate (3%)
- Swelling (3%)
Tiazac and Taztia XT:
- Swelling (up to 15%)
- Dizziness (up to 10%)
- Headache (8%)
- Sore throat (up to 6%)
- Pain (up to 6%)
- Shortness of breath (up to 6%)
- Indigestion (up to 5%)
- Weakness (up to 4%)
Cardizem LA:
- Swelling (8%)
Less Common Side Effects
- Rash
- Diarrhea
- Palpitations (racing heart)
- Nervousness
- Infection or flu-like symptoms
- Cough
- Muscle aches
- Weakness
Diltiazem ER serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- Liver problems: severe nausea, vomiting, right-sided stomach pain, fatigue, low or no appetite, yellowing of the skin or eyes
- Serious allergic and skin reactions: sore throat, fever, fatigue, rash, hives, painful blisters, skin reddening, skin peeling, swollen lymph nodes
- Heart failure: chest pain, difficulty breathing, dizziness, tiredness, swollen legs and feet, bloating
When do Diltiazem ER possible side effects begin and end?
Time passed since treatment started:
H
D
W
M
Headache
Dizziness
Swelling in the legs and feet
If a line continues to the right, you'll likely keep experiencing this side effect once it starts.
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The following Diltiazem ER side effects have also been reported
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
More common
Body aches or pain
congestion
dryness or soreness of the throat
hoarseness
tender or swollen glands in the neck
trouble swallowing
voice changes
Less common
Chest pain or discomfort
chills
difficult or labored breathing
feeling faint, dizzy, or lightheaded
feeling of warmth or heat
flushing or redness of the skin, especially on the face and neck
general feeling of discomfort or illness
headache
joint pain
loss of appetite
muscle aches and pains
shivering
slow or irregular heartbeat
sweating
swelling of the hands, ankles, feet, or lower legs
tightness in the chest
trouble sleeping
unusual tiredness or weakness
vomiting
Incidence not known
Blistering, peeling, or loosening of the skin
large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
no heartbeat
red skin lesions, often with a purple center
red, irritated eyes
sores, ulcers, or white spots in the mouth or on the lips
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Less common
Acid or sour stomach
belching
continuing ringing or buzzing or other unexplained noise in the ears
degenerative disease of the joint
difficulty with moving
hearing loss
indigestion
lack or loss of strength
muscle aching or cramping
muscle pains or stiffness
pain or tenderness around the eyes and cheekbones
rash
stomach discomfort, upset, or pain
swollen joints
Incidence not known
Hair loss or thinning of the hair
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Get your GoodRx coupon
$31.99
GoodRx discount
$11.68
Pros and cons of Diltiazem ER
Pros
- Works well to help with blood pressure or chest pain
- Available as a lower-cost generic
- Can be taken with or without food
- Available as once or twice daily dosing, depending on the brand
Cons
- Interacts with many medications
- Not a good option for people with certain heart problems
- Can cause dizziness or swelling in your hands, feet, and legs
- Can't be used in children
Pharmacist tips for Diltiazem ER
- Take diltiazem ER with or without food at any time of day. If it hurts your stomach, try taking it with food to help.
- Swallow diltiazem ER whole. Don't crush or chew the capsules or tablets because this can damage the medication and the way it's released slowly inside of your body.
- If you are taking Tiazac or Taztia XT, you can open and sprinkle the contents on applesauce and eat it right away. Drink a glass of water afterwards to make sure you swallowed all of the medication.
- It's recommended to measure and record your blood pressure at home and bring a record of your information to your medical appointments. This information will help your provider understand how well diltiazem ER is working for you and if they need to make any changes to your treatment.
- It might take up to 2 weeks before you experience the full effect of diltiazem ER on your blood pressure.
- Take diltiazem ER exactly as prescribed. Don't change your dose or suddenly stop taking the medication without talking to your provider first. Doing so can cause your blood pressure to rise quickly. If you want to stop diltiazem ER, ask your provider if it's safe to do so. You might need to lower your dose slowly over time before you can completely stop taking it.
- You might notice side effects, such as headache, dizziness, or constipation, when you first start taking diltiazem ER or when your provider raises your dose. These should get better over time as you continue taking the medication. Talk with your provider if the side effects are becoming too bothersome.
- You might feel dizzy when you start taking diltiazem ER, and when the dose is raised. This should get better over time as you continue taking the medication and your body gets used to your new blood pressure. If you continue to feel dizzy, talk with your provider.
- Swelling in your feet, ankles, legs, hands, or arms can happen while taking diltiazem ER. Talk to your provider if the swelling becomes too bothersome. They might recommend tips to ease the swelling, such as asking you to sit or lie down with your legs raised or to wear compression socks.
- Diltiazem ER can interact with many other medications such as statins (for cholesterol) and other blood pressure medications. Tell your provider and pharmacist about all of the over-the-counter and prescription medications that you're taking.
- If you're using diltiazem ER for high blood pressure, make sure to have a healthy diet, including a low-salt diet, while taking diltiazem ER so that the medication works even better to lower your blood pressure.
More on Diltiazem ER tips
Risks and warnings for Diltiazem ER
Diltiazem ER can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Slow heart rate or heart block
- Risk factors: Taking beta-blockers or digoxin (Lanoxin) | Having medical conditions that slow your heart rate
Diltiazem ER can cause or worsen heart block, which is when your heart rate is slowed down. This can cause you to feel weak or lightheaded and might even cause you to pass out. You're at higher risk if you're taking digoxin (Lanoxin) or a beta-blocker (e.g., propranolol (Inderal)), or if you have other medical conditions that slow your heart rate. Make sure your provider knows your entire medical history before starting diltiazem ER. Ask your provider if you're not sure whether this medication is safe for you.
Worsening heart failure
- Risk factors: Heart failure | Other heart problems | Taking beta-blockers
Diltiazem ER can worsen heart failure, especially in people who already have heart problems that affect how well blood is pumped to the rest of the body. Let your provider know if you experience symptoms of heart failure, such as chest pain, difficulty breathing, dizziness, tiredness, swollen legs and feet, or bloating.
Severely low blood pressure
- Risk factors: Taking other medications that lower blood pressure
Diltiazem ER can cause your blood pressure to drop too much, which can make you feel dizzy, tired, or lightheaded. This is a common side effect of blood pressure medications, especially when starting the medication and when the dose is raised. If your blood pressure drops too much and you feel too dizzy, make sure to sit down slowly while holding onto something. Let your provider know because they might need to adjust the dose of your medication. If you fall and hit your head, get medical help right away.
Liver problems
Although rare, diltiazem ER can raise your liver enzymes, which can lead to liver problems if not properly treated. This typically occurred within 1 to 8 weeks of starting diltiazem ER. Your provider might check your liver tests before you start this medication and regularly afterwards to make sure it doesn't become a serious problem. If you notice severe nausea, vomiting, right-sided stomach pain, fatigue, low or no appetite, or yellowing of the skin or eyes, get medical help right away.
Severe skin reactions (extended-release tablets only)
In some rare cases, diltiazem ER can cause serious and life-threatening skin reactions called Stevens-Johnson syndrome (SJS) or or toxic epidermal necrolysis (TEN). If you notice changes in your skin (e.g., sore throat, fever, fatigue, rash, painful blisters, skin reddening, skin peeling) or experience swelling in your face or trouble breathing, stop using diltiazem ER and get medical attention right away.
Diltiazem ER dosage
The average cost for 90 capsules of 300mg of Diltiazem ER is $38.07 with a free GoodRx coupon. This is 74.12% off the average retail price of $147.12. 
Capsule
Capsule| Dosage | Quantity | Price as low as | Price per unit |
|---|---|---|---|
| 120mg | 90 capsules | $22.88 | $0.25 |
| 180mg | 90 capsules | $25.55 | $0.28 |
| 240mg | 90 capsules | $30.77 | $0.34 |
| 300mg | 90 capsules | $38.07 | $0.42 |
Typical dosage for Diltiazem ER
Your dose will depend on your condition and the specific diltiazem ER product you're prescribed.
-
Diltiazem once-daily extended-release capsules (e.g., Cardizem CD, Cartia XT, Tiazac, Taztia XT, generic):
- High blood pressure: The typical starting dose ranges from 120 mg to 240 mg by mouth once daily, depending on which product you're prescribed. The typical maintenance dose ranges from 120 mg to 540 mg daily.
- Chest pain: The typical starting dose ranges from 120 mg to 180 mg by mouth once daily, depending on which product you're prescribed. The maximum recommended dose is 540 mg daily.
-
Diltiazem twice-daily extended-release capsules:
- High blood pressure: The typical starting dose ranges from 60 mg to 120 mg by mouth twice daily. The typical maintenance dose ranges from 120 mg to 180 mg twice daily.
-
Diltiazem extended-release tablets (e.g., Cardizem LA, generic):
- High blood pressure: The typical starting dose ranges from 180 mg to 240 mg by mouth once daily. The maximum recommended dose is 540 mg daily.
- Chest pain: The typical starting dose is 180 mg by mouth once daily. The maximum recommended dose is 360 mg daily.
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Interactions between Diltiazem ER and other drugs
Diltiazem ER may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Diltiazem ER. Please note that only the generic name of each medication is listed below.
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Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
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
- Eliglustat
- Flibanserin
- 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.
- Abametapir
- Acalabrutinib
- Acebutolol
- Alfentanil
- Alprazolam
- Alprenolol
- Amiodarone
- Aprepitant
- Atazanavir
- Atenolol
- Atorvastatin
- Avapritinib
- Benzhydrocodone
- Betaxolol
- Bevantolol
- Bisoprolol
- Bosutinib
- Brexpiprazole
- Brigatinib
- Bucindolol
- Buprenorphine
- Carbamazepine
- Carteolol
- Carvedilol
- Celiprolol
- Ceritinib
- Cilostazol
- Clarithromycin
- Clonidine
- Clopidogrel
- Clozapine
- Cobimetinib
- Codeine
- Conivaptan
- Crizotinib
- Cyclosporine
- Dantrolene
- Deflazacort
- Digoxin
- Dihydrocodeine
- Dilevalol
- Domperidone
- Doxorubicin
- Doxorubicin Hydrochloride Liposome
- Dronedarone
- Droperidol
- Elexacaftor
- Encorafenib
- Entrectinib
- Epirubicin
- Eplerenone
- Erythromycin
- Esmolol
- Fentanyl
- Fingolimod
- Fosaprepitant
- Fosnetupitant
- Hydrocodone
- Ibrutinib
- Ifosfamide
- Ivabradine
- Ivacaftor
- Ivosidenib
- Labetalol
- Lacosamide
- Lemborexant
- Levobunolol
- Lovastatin
- Lumateperone
- Lurasidone
- Lurbinectedin
- Meperidine
- Mepindolol
- Methadone
- Metipranolol
- Metoprolol
- Morphine
- Morphine Sulfate Liposome
- Nadolol
- Naloxegol
- Nebivolol
- Netupitant
- Nilotinib
- Olaparib
- Oxprenolol
- Oxycodone
- Pemigatinib
- Penbutolol
- Pentazocine
- Pexidartinib
- Pindolol
- Piperaquine
- Pixantrone
- Ponesimod
- Propranolol
- Ranolazine
- Rimegepant
- Selpercatinib
- Selumetinib
- Simeprevir
- Simvastatin
- Siponimod
- Sonidegib
- Sotalol
- St John's Wort
- Sufentanil
- Tacrolimus
- Talinolol
- Tazemetostat
- Tertatolol
- Tezacaftor
- Timolol
- Tolvaptan
- Tramadol
- Ubrogepant
- Venetoclax
- Voclosporin
- Zanubrutinib
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.
- Alfuzosin
- Apixaban
- Buspirone
- Cimetidine
- Colestipol
- Dalfopristin
- Digitoxin
- Dutasteride
- Efavirenz
- Enflurane
- Fosphenytoin
- Guggul
- Indinavir
- Lithium
- Methylprednisolone
- Midazolam
- Moricizine
- Nevirapine
- Phenytoin
- Quinupristin
- Rifampin
- Rifapentine
- Rivaroxaban
- Sirolimus
- Suvorexant
- Triazolam
How much does Diltiazem ER cost?
To access savings, use a GoodRx coupon and pay just a fraction of the retail price.
Diltiazem ER contraindications
Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Diltiazem ER will not be safe for you to take.
- Sick sinus syndrome (except if you have a ventricular pacemaker)
- Second- or third-degree AV block (except if you have a ventricular pacemaker)
- Uncontrolled hypotension (less than 90 mm Hg systolic)
- Active heart attack and congestion in the lungs
What are alternatives to Diltiazem ER?
There are a number of medications that your doctor can prescribe in place of Diltiazem ER. Compare a few possible alternatives below.
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Diltiazem ER images
