What is Diltiazem?

Diltiazem is in the family of medications known as calcium channel blockers. This medication blocks the movement of calcium into muscle cells, which helps to relax the heart muscle, dilate the arteries, and slow down the electrical impulses that go through the heart. The medication is rapidly absorbed after being administered and metabolized by the liver and can sometimes cause increased liver enzymes (more on this below).

Diltiazem is often used in emergency situations to stabilize your pet, but also long-term to help manage your cat or dog’s heart conditions. Your pet will most likely be prescribed diltiazem if they need treatment of specific cardiac diseases and arrhythmias.

Keeping your pet happy, safe, and healthy is a no-brainer for most cat and dog owners. That means frequent check-ups at the vet, consistent grooming, and sometimes making sure your pet takes their daily medications. Yes, getting your cat or dog to take a drug like diltiazem is never fun (we’ve all had to do the “hide the pill in cheese” method), but it’s medications like these that can sometimes help your furry friend live that happy and healthy life that you’re looking for!

Here at CVCA, our board-certified veterinary cardiologists want all of our patients and their owners to feel confident about the medications that are being administered to your pet. On our medications pages, you’ll find a comprehensive description of the medication, its common uses, side effects, and much more. So keep reading to learn more about diltiazem for dogs and cats and what you should be aware of when your pet is taking this medication.

What is Diltiazem Used to Treat?

Taking care of your pet’s heart and cardiac health is our top priority at CVCA. If you’re reading this page, you’ve likely been prescribed diltiazem for dogs or cats for a specific heart-related illness. Here are a few of the most common diseases that diltiazem is used to treat:

  • Hypertrophic Cardiomyopathy: A heart muscle disease where the walls of the heart thicken, resulting in less blood flow to the body.
  • Heart Rate Control: Some patients with Atrial Fibrillation (a disease where the heart muscles contract and cause irregular rhythms) are prescribed diltiazem to help regulate the muscle contractions in the heart.
  • Supraventricular Arrhythmias: When your cat or dog has a heartbeat that is too fast, it may be caused by a disruption of the normal electrical impulses of their heart.
  • Systemic and Pulmonary Hypertension: Diltiazem is rarely used to treat systemic and pulmonary hypertension, but it can help dilate the arteries to help regulate blood pressure.

What Are Some Adverse Effects of Diltiazem?

As with any medication, your pet could have an allergic reaction or any number of other negative responses—diltiazem side effects are no different. If you notice any adverse effects in your pet after taking this medication, contact your veterinarian as soon as possible. Also, please contact CVCA should any of these symptoms be noted:

  • Vomiting and Decreased Appetite: These are two of the most common side effects of diltiazem. It is not a cause for worry most of the time, but talking to a veterinary medicine expert at CVCA can help with figuring out the correct dosage to make your pet’s life more comfortable.
  • Excess Salivation and Food Aversion: Due to its bitter taste, diltiazem can cause excessive salivation and food aversion in your cat or dog. Talk to your board-certified veterinary cardiologists at CVCA for ways to help lessen these side effects.
  • Low Blood Pressure, Weakness, Lethargy, and Slow Heart Rate: These less common side effects are more serious causes for concern. If you notice your pet seems weak or lethargic, let us know so we can ensure your pet is as healthy and comfortable as possible.
  • Elevated Liver Function and Constipation: These are rarer side effects but can be cause for concern in your cat or dog. If your pet seems weak, collapses, develops a rash, or has pale gums, give CVCA a call immediately.

Interactions with Other Drugs

Before administering diltiazem to your cat or dog, make sure that your veterinarian is already aware of any other medications your pet is on. The board-certified veterinary cardiologists at CVCA have already taken these medications and interactions into account, but please contact us regarding any other concurrent medications your pet may be prescribed. Here are some of the common interactions we see:

  • Beta-Blockers (Atenolol), Amlodipine, Acepromazine, Acei (Enalapril, Benazepril): When diltiazem is used in combination with any of these medications, there is an increased risk of low heart rate and low blood pressure.
  • Benzodiazepines (Valium/Alprazolam) and Cyclosporine: Diltiazem can increase the strength of these certain drugs.
cat getting a checkup

Patient Information on Diltiazem

At CVCA, we want to make sure you’re aware of all of the possible diltiazem side effects and know how to easily administer the medication. Your CVCA veterinarian will give you detailed instructions, but here are a few essential tips to remember:

  • Diltiazem can be given with food and other cardiac medications as outlined by CVCA.
  • This medication is given in pill form or reformulated into a flavored liquid, whatever is easiest for your cat or dog.
  • Depending on drug formulation and/or the disease being treated, diltiazem is given 1 to 3 times daily.
  • We recommend closely monitoring your cat or dog’s blood pressure and heart rate while on this medication.
  • Do not abruptly stop or reduce this medication therapy without your veterinarian’s approval.
  • If anesthesia is required to administer the medication, contact your veterinarian about the dosage.

Dosage Forms of Diltiazem

Diltiazem for dogs and cats comes in several medication forms. If your pet has difficulty taking one type of this medication, talk to one of the vets at CVCA to see what other forms may be possible. Here are the most common dosages you will see prescribed:

  • Diltiazem Tablets – 30mg, 60mg, 90mg, and 120mg
  • Diltiazem Extended-Release Oral Capsules – 120mg, 180mg, and 240mg
    • Note: You may need to open the capsule and remove the four individual tablets and administer one or more of the tablets, depending on dosage requirements
  • Cardizem CD Capsules – 120mg, 180mg, 240mg, and 300mg
    • Note: These capsules should be swallowed whole and not chewed.

Diltiazem Synonyms

Diltiazem is a type of medication, not a brand name. Your pet’s medication may be listed as one of the following synonyms for the drug:

  • Cardizem, Cardizem CD, Dilacor XR

Do You Have Questions About Your Pet’s Medications?