Diltiazem Dosages: Your GoodRx Guide

Diltiazem is a medication that treats various heart conditions. It’s part of a group of medications called calcium channel blockers (CCBs). It comes as an immediate-release (IR) tablet and injection. It also comes as an extended-release (ER) tablet and capsule. All forms of diltiazem are available as brand-name and lower-cost generic versions.

Finding the right diltiazem dosage for you can be tricky. But taking the right dose is important to help you best manage your heart condition and lower your risk of unwanted side effects. 

In this guide, we’ll cover the FDA-approved diltiazem dosages for the oral formulations of diltiazem. Sometimes, though, your healthcare provider may prescribe something different than what’s discussed below. If you have questions about your dose, be sure to speak with your provider and follow their instructions closely.

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What’s the typical diltiazem dosage for adults?

There isn’t one diltiazem dosage that’s best for everyone. The dose that’s best for you depends on what condition you’re treating, what diltiazem product you’re taking, and other personal factors. We discuss the different diltiazem formulations and their FDA-approved uses in the table below.

Keep in mind: If you’re taking diltiazem IR, it’s possible that your healthcare provider recommends switching to diltiazem ER at some point. Or you may switch between different diltiazem ER products. But you may need a different dose when you make the switch. This is because ER products are released in the body over a longer period of time than IR products. And what’s more, different diltiazem ER products may have different instructions for using them. So always check with your provider before switching from one diltiazem product to another.

Chest pain

Listed below are the usual starting and maintenance doses of diltiazem for chest pain. The IR tablets need to be taken more frequently because they only last a few hours in the body.

High Blood Pressure

Only diltiazem ER formulations are FDA approved to treat high blood pressure. Some of the usual starting and maintenance dosages are detailed below.

Are there any dosage adjustments for medical conditions or drug interactions?

Diltiazem is metabolized (broken down) by the liver. And it’s partially excreted (removed by the body) when you pee, which involves the kidneys. If you have existing liver or kidney problems, your healthcare provider might start you at a lower dose so the kidneys don’t have to work as hard to process diltiazem. Make sure they know your full medical history so they can adjust your diltiazem dosage as needed.

If you’re taking other blood pressure medications in addition to diltiazem, your healthcare provider might tinker with your dosages. They could prescribe a lower dose of diltiazem or your other blood pressure medications to make sure your blood pressure doesn’t drop too low. But don’t make any changes without talking to your provider first. 

Some other medications may also interact with diltiazem. This may require a change in doses, or a change in medications altogether. Give your provider and pharmacist a list of medications, supplements, and herbs you take before starting diltiazem. They can check to see if you’re at risk of any diltiazem interactions.

What happens if you miss a dose of diltiazem?

If you miss a dose of diltiazem, take it as soon as you remember. But if it’s close to your next scheduled dose, skip the missed dose and return to your usual dosing schedule. Never take two doses at once to make up for a missed dose.

If you’ve missed several doses in a short amount of time, your blood pressure could rise too high. Be sure to tell your healthcare provider if you’ve missed multiple doses of diltiazem.

What should you do if you take too much diltiazem?

Taking too much diltiazem can make side effects more likely. This includes swelling in the legs, tiredness, and dizziness. If you take an especially large dose of diltiazem, it can be life-threatening. Possible signs of toxicity include:

• Dizziness, agitation, or confusion

• Losing consciousness

• Low heart rate or blood pressure

• Heart rhythm problems

• Trouble breathing

• Nausea and vomiting

The exact diltiazem dose that’s considered toxic isn’t known. It can vary from person to person. But reports of diltiazem toxicity have occurred with doses that are less than 1,000 mg. And symptoms may not show up for many hours, especially with ER formulations. So it’s important to carefully follow your provider’s dosage instructions when taking diltiazem.

If you or a loved one may have taken too much diltiazem and you’re experiencing symptoms, call 9-1-1 or Poison Control at 800-222-1222.

How to save on diltiazem

Diltiazem IR and Diltiazem ER products are available as lower-cost generics. GoodRx can help you save over 70% off the average retail price of the generic version of diltiazem IR and diltiazem ER. 

Generic diltiazem IR’s price at certain pharmacies may be as low as $17.31 with a free GoodRx discount. And generic diltiazem ER capsules at certain pharmacies may be as low as $9.00 with a free GoodRx discount.

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Written by:

Daphne Berryhill, RPh

Daphne Berryhill, RPh, has two decades of experience as a clinical pharmacist. She spent most of her career in the Chicago area practicing in-home infusion.

Edited by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Reviewed by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

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