Get a Tiazac (Diltiazem ER) prescription online

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Diltiazem ER is used to treat high blood pressure (hypertension). Lowering blood pressure can reduce the risk of heart problems, kidney disease and stroke. This medicine is a calcium channel blocker (CCB) that relaxes blood vessels and reduces strain on the heart. Cardizem LA and Tiazac are other brands of Diltiazem ER.

Please note: At this time, this medication is only prescribed as a refill at Dr. B.

* Prescription treatment requires a virtual medical consultation with a medical provider to determine if a prescription is appropriate.

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How Dr. B treats high blood pressure

Health assessment

Tell us about your condition with a $15 online consultation—no video call necessary.

Provider review

A medical provider will review your information and prescribe treatment, if appropriate.

Get your medication

Pick up and pay for the medication at the pharmacy of your choice. Or, get it delivered.

About Tiazac (Diltiazem ER)

How does it work?

Diltiazem ER is a calcium channel blocker. This class of medicines help relax blood vessels and reduce the heart's workload. This results in more oxygen to the heart and improved blood flow.

What does it treat?

This medication is used to treat high blood pressure (hypertension). It can also help regulate some kinds of abnormal heart rhythms.

What forms does it come in?

This hypertension medicine comes as an extended-release capsule. These capsules provide a gradual and steady release of the medication into the bloodstream, so they’re only taken once or twice a day.

Tiazac vs. Diltiazem ER

Tiazac and Diltiazem ER are essentially the same medication. Diltiazem ER is the generic version and Tiazac is a brand name. Brand and generics contain the same active ingredients that help treat hypertension.

How much will it cost?

Dr. B offers online consultations for $15—which is less than most copays. If a high blood pressure prescription is appropriate, your out-of-pocket medication cost will depend on your insurance and where you decide to get your prescription filled. With a drug discount card, prices for Diltiazem ER 24 hr 120 mg (30 capsules) start at $6.59.

* Prices shown with drug discount card applied. Price may differ depending on location.

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Starting at

Diltiazem ER 24 hr 120 mg (30 capsules)*

More High Blood Pressure (Hypertension) Prescription Refills

Looking for a different hypertension medication? Here are some options.

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Common Questions

Tiazac (Diltiazem ER) prescription FAQ

What are the benefits of taking Tiazac (Diltiazem ER)?
  • Lowers blood pressure
  • Regulates heart rhythm
  • Improves heart function
  • Improves blood flow to heart
  • Reduces risk of heart attack and stroke
  • Reduces risk of kidney damage from high blood pressure
Who should not take this medication?
  • Those who are allergic to Diltiazem 
  • People with a known allergy or severe reaction to Calcium Channel Blockers (CCBs)
  • Pregnant women, breastfeeding or those planning to become pregnant
  • Those with a history of liver problems
  • People with severe heart conditions or heart failure
  • People who have slow heart rate (bradycardia) 
  • Those with low blood pressure (hypotension)
  • Those with myasthenia gravis (muscle disorder)
  • People with sick sinus syndrome (a heart rhythm problem)
  • Those who have second- or third-degree atrioventricular block (a heart rhythm problem)

If you have any of these conditions—or Raynaud's syndrome (a condition that causes the fingers and toes to become numb and cold), asthma, other respiratory issues, a history of significant lung diseases, porphyria (a rare blood disorder), kidney complications, or diabetes—speak with your healthcare provider before starting this medication.

Taking this medication when you have these conditions should be carefully and closely monitored by a healthcare provider.

Also tell your medical provider about any other medications you’re using before you start this hypertension treatment.

How do you take this medication?

Swallow the capsules whole, with or without food, as directed by your health provider. Do not crush, chew or break them–this could change how the medicine works.

High blood pressure is a long-term (chronic) condition that can harm your organs. Medications for blood pressure are not a one-time cure. This medicine doesn't provide a complete cure for high blood pressure, so it's important to continue taking it, even if you start feeling better. If you stop taking it suddenly, this could cause dangerous problems, like heart attack or stroke. Follow your medical provider's instructions carefully.

What happens if I miss a dose?

If you miss a dose of your blood pressure medicine, take it as soon as you remember. But skip the missed dose if it’s almost time for your next dose. Do not double the dose to make up for the missed one.

What happens if I take too much?

Taking too much of your blood pressure medicine can lead to symptoms like low blood pressure, hyperglycemia (high blood sugar), slow heart rate, dizziness and fainting.

If you’ve taken too much Diltiazem ER, call your licensed medical provider or local poison control center (800-222-1222) immediately.

Can I get Tiazac (Diltiazem ER) online?

If you need a refill of your high blood pressure (hypertension) medication, you can get a convenient online prescription through Dr. B. Just complete a short health questionnaire to start the process.

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Side Effects

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Some people report side effects while taking Diltiazem ER. You might notice:

  • Headache
  • Dizziness or lightheadedness
  • Stomach upset
  • Constipation
  • Weakness
  • Sore throat
  • Swelling of arms, legs, hands or feet

Tell your health provider if your side effects are bothersome or don’t go away. Also report any serious side effects, like problems breathing, chest pain or tightness, blisters or rash or yellowing skin or eyes.

Don’t drive until you know how this medicine affects you. Be extra careful in the first hours after taking your pill because of the risk of dizziness or lightheadedness.

Getting your blood tested regularly is important to monitor your overall health. It's a good idea to have your bloodwork checked, which may include tests for renal function, glucose levels or potassium levels in your blood. These routine checks help ensure you are in good health and catch any potential issues early.