By Rania Gollakner, BS, DVM, MPH

What is amlodipine?

Amlodipine (brand names: Norvasc®, Amodip®, Copalia®, Katerzia®) is a calcium channel blocker used for treating high blood pressure, most commonly in cats, in order to prevent damage to the kidneys, eyes, and brain.

Its use in cats and dogs to treat high blood pressure is ‘off label’ or ‘extra label’. Many drugs are commonly prescribed for off label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully as their directions may be significantly different from those on the label.

How is amlodipine given?

Amlodipine is given by mouth in the form of a tablet or compounded liquid solution. It may be given with or without food, however if vomiting occurs when dosed on an empty stomach, give future doses with food. Measure liquid forms carefully. It is important to not miss or skip doses; do not stop this medication before talking to your veterinarian.

This medication should take effect within 1 to 2 hours; however, effects may not be visibly obvious and therefore laboratory tests may need to be done to evaluate this medication’s effectiveness.

What if I miss giving my pet the medication?

Give the missed dose as soon as you remember, and then wait the recommended amount of time between doses. Never give your pet two doses at once or give extra doses.

Are there any potential side effects?

Side effects in cats may include vomiting, diarrhea, lack of appetite, or sleepiness. Side effects in dogs may include gingival (gum) overgrowth. Serious side effects include a very low or very fast heart rate, collapse, severe weakness, changes in urination, limb swelling, or abnormal bleeding.

This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

Amlodipine should not be used in pets that are allergic to it, that are in shock, that have aortic stenosis, or are in liver failure. It should be used cautiously in pets with heart failure, liver disease, at risk for low blood pressure, and in pets that are pregnant and/or lactating, as safety has not been established.  

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with amlodipine: clopidogrel, cyclosporine, CYP3A4 inducers such as azole antifungals and rifampin, negative chronotropes, tacrolimus, and hypotensive agents.

Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.

Is there any monitoring that needs to be done with this medication?

Your veterinarian will need to monitor your pet’s blood pressure regularly to be sure that the medication is working and to adjust the dose. Eye exams and potassium levels may also be monitored regularly.

How do I store amlodipine?

Store at room temperature between 68°F and 77°F (20°C and 25°C ) with short trips between 59°F and 86°F (15°C and 30°C ) permitted. Protect from moisture and light. Store the veterinary chewable tablets in the blister packaging until ready to use; tablets removed from the blister pack must be used within 24 hours. The compounded liquid form should be stored between 41°F and 77°F (5°C and 25°C ) and protected from light, unless otherwise instructed on the label.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.

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