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Calcium channel blocker (antihypertensive) · For Cats

Norvasc dosage reference for cats (Amlodipine)

This page's standard weight-based reference is 0.18 mg per kg (0.08 mg per lb), with once daily recorded as the reference frequency. Use the calculator to see the arithmetic for your cat's weight, then confirm the indication, product, and actual dose with a veterinarian.

Onset
1-2 hours; full effect in 1-2 weeks
Duration
24 hours
Class
Calcium channel blocker (antihypertensive)

Weight-based calculator estimate from the references listed on this page. This page has not been independently DVM-reviewed — see our methodology .

This information is for educational purposes only. Always consult your veterinarian before giving medication to your pet. Do not use this calculator for emergencies, overdoses, pregnancy, very young animals, very old animals, pets with liver/kidney disease, or pets taking multiple medications.

Each medication page lists the references recorded for its data. The calculator math and editorial presentation are maintained by PetDosageChart; a page is independently DVM-reviewed only when a named reviewer byline appears. See our methodology and limitations.

Amlodipine (often known by brand names such as Norvasc and Amodip) is a calcium channel blocker (antihypertensive) commonly used in veterinary medicine for hypertension (high blood pressure), hypertension secondary to chronic kidney disease, hypertension secondary to hyperthyroidism, and retinal protection in hypertensive cats. Understanding the correct dosage, administration, and potential side effects of Amlodipine is critical for your cat’s safety and well-being.

A typical Amlodipine dose for cats is around 0.18 mg/kg once daily, within a usual range of 0.125-0.25 mg/kg. Available forms include tablet.

Calculator Warning: Use this only as an educational estimate. Your veterinarian may prescribe a different dose based on your pet’s condition, age, weight, other medications, and medical history.

Amlodipine Dosage Calculator for Cats

Enter your cat’s weight below to estimate the Amlodipine dose from the 0.18 mg/kg guideline. Your veterinarian may adjust it for your cat’s age, condition, and other medications, so treat the result as an educational starting point, not a prescription.

Dosage Calculator · 01

Enter your cat's weight

Quick Dosage Chart

Typical Amlodipine amounts for common cat weights, for quick reference:

Dosage Chart · 02

Norvasc weight-based reference chart for cats

Scroll sideways to see full table

Weight Lower Reference Standard Reference Upper Reference Frequency
3 lbs (1.4 kg) 0.17 mg 0.25 mg 0.35 mg once daily
4 lbs (1.8 kg) 0.23 mg 0.32 mg 0.45 mg once daily
5 lbs (2.3 kg) 0.29 mg 0.41 mg 0.57 mg once daily
6 lbs (2.7 kg) 0.34 mg 0.49 mg 0.68 mg once daily
7 lbs (3.2 kg) 0.40 mg 0.58 mg 0.80 mg once daily
8 lbs (3.6 kg) 0.45 mg 0.65 mg 0.90 mg once daily
9 lbs (4.1 kg) 0.51 mg 0.74 mg 1.0 mg once daily
10 lbs (4.5 kg) 0.56 mg 0.81 mg 1.1 mg once daily
12 lbs (5.4 kg) 0.68 mg 0.97 mg 1.4 mg once daily
14 lbs (6.3 kg) 0.79 mg 1.1 mg 1.6 mg once daily
16 lbs (7.3 kg) 0.91 mg 1.3 mg 1.8 mg once daily
18 lbs (8.2 kg) 1.0 mg 1.5 mg 2.0 mg (2.5mg tablet) once daily
20 lbs (9.1 kg) 1.1 mg 1.6 mg 2.3 mg (2.5mg tablet) once daily
25 lbs (11.3 kg) 1.4 mg 2.0 mg (2.5mg tablet) 2.8 mg (2.5mg tablet) once daily

Parenthetical tablet amounts are arithmetic comparisons only. They do not account for scoring, release type, concentration, product labeling, or whether this medication is appropriate for an individual animal.

By Weight

Norvasc reference by cat weight

Choose a common weight to open its optional reference page. Use the main medication calculator for a different exact weight.

Common-weight pages are convenience views of the same educational reference, not separate medical recommendations.

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How to Give Amlodipine to Your Cat

Amlodipine is the drug of choice for feline hypertension. The typical starting dose is 0.625 mg (one-quarter of a 2.5 mg tablet) once daily for an average-sized cat. The tiny tablet fragment can be hidden in a pill pocket, soft treat, or wet food. Blood pressure should be rechecked 1-2 weeks after starting and after any dose change. Consistency in daily timing helps maintain stable blood pressure control.

It is generally recommended to give Amlodipine with food to help reduce stomach upset. It may interact with beta-blockers (additive blood pressure lowering), cyclosporine, other antihypertensive drugs, and sildenafil.

Side Effects and Safety

Common side effects include mild decrease in appetite, mild lethargy, gingival hyperplasia (gum overgrowth) with long-term use, and mild GI upset. More serious side effects can occur, such as dangerously low blood pressure (hypotension), rapid heart rate (reflex tachycardia), worsening kidney function, and acute blindness if hypertension is untreated.

Cautions · 12

When Norvasc should be used with caution or avoided

Some cats should not take Norvasc, or need a different dose and closer monitoring. Tell your veterinarian about your pet's full health history and every other medication or supplement they take before giving Norvasc.

  • severe aortic stenosis
  • known hypersensitivity
  • severe hypotension
  • pregnancy

Interactions · 13

Norvasc drug interactions

Norvasc can interact with other drugs. This list is not complete — always give your veterinarian a full list of your cat's medications and supplements.

beta-blockers (additive blood pressure lowering)
cyclosporine
other antihypertensive drugs
sildenafil

Calculator Limits · 14

When not to use this calculator

This calculator gives a general educational estimate for a healthy adult cat at a known weight. Do not rely on it in these situations — talk to your veterinarian instead:

  • In an emergency, or after accidental ingestion or a suspected overdose
  • For pregnant or nursing pets
  • For very young or very old cats
  • For pets with liver disease, kidney disease, or another chronic illness
  • For pets taking several medications at once
  • When you are not sure of your cat's current, accurate weight
  • For combination products that contain additional active ingredients

Overdose · 15

Suspected overdose: what to do

If you think your cat had too much Norvasc, or swallowed any medication by accident, act right away. Do not wait for symptoms to appear.

  • Call your veterinarian or the nearest emergency animal hospital.
  • ASPCA Animal Poison Control Center: (888) 426-4435
  • Pet Poison Helpline: (855) 764-7661

A consultation fee may apply to the poison hotlines. Have the medication packaging ready, and note how much your pet may have taken and when. Do not try to make your pet vomit unless a veterinarian tells you to.

When to Call the Vet

If your cat experiences any of the following, contact your veterinarian or an emergency clinic immediately:

Frequently Asked Questions

Frequently Asked · 07

Questions about this medication

Why is high blood pressure dangerous in cats?
Uncontrolled hypertension in cats damages the eyes (causing sudden blindness from retinal detachment), kidneys (accelerating chronic kidney disease), heart (causing thickening of the heart muscle), and brain (causing seizures or disorientation). The most devastating and visible consequence is sudden blindness, which can be permanent if blood pressure is not quickly controlled.
How common is high blood pressure in senior cats?
Very common — studies show 20-65% of cats with chronic kidney disease (CKD) develop hypertension, and it frequently accompanies hyperthyroidism. All cats over 10 years old should have regular blood pressure checks, especially if they have kidney disease, thyroid disease, or diabetes. It is often called a "silent killer" because signs may not be obvious until organ damage occurs.
Can amlodipine restore vision in cats with hypertensive blindness?
If caught very early (within 24-48 hours of vision loss), rapidly lowering blood pressure with amlodipine can sometimes restore partial or full vision by allowing the detached retinas to reattach. However, if treatment is delayed, blindness is often permanent. This is why routine blood pressure screening in senior cats is so important.
How long does a cat need to take amlodipine?
Amlodipine is typically a lifelong medication, as feline hypertension is usually secondary to chronic conditions like kidney disease or hyperthyroidism that do not resolve. Regular blood pressure monitoring (every 3-6 months) ensures the dose remains appropriate as the underlying condition progresses.
Is amlodipine the only blood pressure medication for cats?
Amlodipine is the first-line and most effective antihypertensive for cats. It is significantly more reliable at lowering blood pressure in cats compared to ACE inhibitors (benazepril) or beta-blockers, which are often used in other species. In refractory cases, amlodipine may be combined with telmisartan (Semintra) for added effect.

Use This Guide Safely · 08

What weight alone cannot tell you

The calculator performs one narrow job: it multiplies your cat's weight by the lower, standard, and upper mg/kg values recorded for Norvasc. It cannot decide whether this drug, indication, formulation, or schedule is appropriate for an individual animal.

Context in this medication record

Commonly listed uses
hypertension (high blood pressure), hypertension secondary to chronic kidney disease, hypertension secondary to hyperthyroidism, retinal protection in hypertensive cats
Recorded forms
tablet
Reference timing
once daily; onset 1-2 hours; full effect in 1-2 weeks; duration 24 hours

Individual checks a calculator cannot perform

  • Confirm the diagnosis and the reason this medication is being considered.
  • Match the exact product, concentration, route, and whether a tablet may be split.
  • Account for age, pregnancy, organ function, genetics, allergies, and prior reactions.
  • Review every prescription, over-the-counter product, and supplement your pet takes.

Recorded cautions

severe aortic stenosis; known hypersensitivity; severe hypotension; pregnancy.

Recorded interactions

beta-blockers (additive blood pressure lowering); cyclosporine; other antihypertensive drugs; sildenafil.

These lists reproduce the structured record used by this page and may not be exhaustive. Show your veterinarian the product label and your cat's complete medication list before acting on a number.

Related · 08

Related medications for cats

Sources · 09

Sources & references

The structured medication record behind this page names the references below. The links open the publisher or official resource; they do not turn this page into a prescription for an individual animal.

Source names are shown at the record level; passage-level page and label citations are still being added. Read our methodology and limitations.

Transparency · 11

How this page was made

This page's structured medication record includes Plumb's Veterinary Drug Handbook among its source names. PetDosageChart applies the record's mg/kg values to the entered weight and presents the arithmetic result. A source record is not the same as an individualized prescription or an independent clinical review.

Sources cited
  • Plumb's Veterinary Drug Handbook
  • Merck Veterinary Manual
Calculator formula
Doses scale linearly from a standard basis of 0.18 mg per kg (0.08 mg per lb) of body weight, given once daily. The calculator multiplies that basis by your cat's weight and shows an arithmetic comparison with recorded tablet sizes. That comparison does not determine whether a tablet is scored, splittable, or appropriate for your pet.
Editorial owner
Prepared and maintained by the PetDosageChart editorial team, a software-led publisher and not a veterinary practice.
DVM review status
Not independently DVM-reviewed. A named reviewer and review date appear here only after a confirmed review.

More on our methodology and editorial process — how we source, calculate, and review cats dosage data.

Safety · 10

More resources