Hypertension (High Blood Pressure) in Cats

Hypertension in cats is more common in seniors than most pet parents realize.  

As cat blood pressure is affected by kidney and thyroid disease, cats with these conditions should have their blood pressure checked on a regular basis.  

While untreated high blood pressure often results in retinal detachment and sudden blindness, hypertension in cats can be readily managed with a daily pill. 

What Is Hypertension in Cats?

Hypertension in cats occurs when high blood pressure is present throughout the entirety of a feline’s body. 

When a cat’s heart contracts, it pushes blood throughout the body and creates pressure on the walls of the arteries. This pressure is called systolic blood pressure (SBP). 

When the heart relaxes and fills with blood, the pressure on the artery walls is called diastolic blood pressure (DBP). So, blood pressure is a measurement of the amount of pressure on the artery walls. 

A cat’s blood pressure is measured in the same way as a human’s, with the systolic number over the diastolic number, measured in millimeters of mercury, or mmHg. 

In cats, the diastolic blood pressure measurement (the bottom number), is less reliable and considered a less important component of hypertension. So, hypertension in cats is typically diagnosed based on an elevated systolic blood pressure (top number). 

Hypertension in cats is generally diagnosed when the SBP is greater than 160 mm Hg or if the SBP is greater than 150 mmHg and there is clear evidence of organ damage due to hypertension. 

What Is a Normal Cat Blood Pressure?

Cats are hooked up to a blood pressure cuff, just like people.  

The cuff will tighten and the doctor will get a reading. A normal cat blood pressure should be under 150 mmHg (millimeters of mercury). 

Many cats are stressed while they’re in the hospital. Because of this stress, their blood pressure may be slightly elevated. Vets call this “white coat syndrome.”  

It’s not unusual to see cats with normal blood pressure outside the hospital, have more borderline hypertensive values in the 150-180 mmHg range. For these cats, the vet will often recommend continued monitoring and not starting medication right away. 

Your vet may want to give your cat a little time (about five to 10 minutes to calm down), have a treat and relax in the clinic. They may repeat the reading to see if they are still borderline, or if their blood pressure is coming down. 

Hypertension is usually diagnosed in cats with blood pressure readings over 180 mmHg. For these kitties, the vet will recommend treatment. 

Hypertension in Cats Symptoms

Some pets may have no symptoms. If signs of hypertension in cats do appear, they may include: 

• Fixed, dilated pupils 

• Blood in the clear chamber of the eye 

• Sudden blindness, bumping into objects 

• Disorientation 

• Stumbling, poor balance (ataxia) 

• Back leg weakness 

• Behavior changes, seeming “out of it” 

• Seizures 

• Decreased appetite 

• Vomiting 

• Weight loss 

What Causes High Blood Pressure in Cats?

In most cases, high blood pressure in cats is due to or associated with an underlying disease. This is called secondary hypertension. 

The two most common underlying conditions of hypertension in cats are: 

• Chronic kidney disease (CKD) is the most common disease associated with hypertension in cats and is found in up to 74% of cats with hypertension. 

• Hyperthyroidism, a disease caused by a tumor on the thyroid gland (usually benign), is also commonly present in cats with hypertension. 

Uncommon diseases that are linked to a higher risk of feline hypertension include: 

• Hyperaldosteronism 

• Hyperadrenocorticism (Cushing’s disease) 

• Diabetes mellitus 

• Pheochromocytoma 

These diseases are diagnosed most frequently in senior and geriatric cats. 

Certain medications—such as steroids (like prednisolone) and phenylpropanolamine—may also lead to high blood pressure in cats. 

About 20% of cats have idiopathic hypertension, meaning that an underlying cause is unable to be found. A portion of these cats are likely in the very early stages of chronic kidney disease, before abnormalities can be detected by a vet. 

How Do You Take a Cat's Blood Pressure? 

If you want to try and take your cat’s blood pressure at home, you’ll need a specialty veterinary monitor and an appropriately sized blood pressure cuff.  

At home monitors may not be as accurate as those used in the veterinary office, so be sure to have your vet double check if you’re getting concerning readings. 

The cuff should be approximately 40% of the limb’s circumference so that it’s snug, but not too tight. Veterinary cuffs often have an optimal zone on the back. 

Make sure your cat is calm and relaxed before you take the measurement so that it’s as accurate as possible. 

Position the cuff on the front leg, back leg, or tail with the sensor over the artery. Inflate the cuff (there will usually be a start button) and try to keep your pet as still as possible while the machine takes a reading. 

• Normal: Less than 150 mmHg 

• Prehypertension: 151-180 mmHg 

• Hypertension: 181-200 mmHg 

• Severe hypertension: Greater than 200 mmHg 

Hypertension in Cats Treatment

Hypertension in cats is treated with oral medications. 

Amlodipine is the medication of choice used to treat hypertension in cats. 

It comes in a pill form and is given orally once daily. 

If you have a hard time giving pills to your cat, your veterinarian may have the medication compounded into a liquid. 

The goal of hypertension treatment is to minimize the symptoms associated with organ damage and to reduce your cat’s blood pressure to less than 150 mmHg. 

In some cases, additional medications—such as ACE inhibitors or telmisartan—may be necessary. 

Aside from using medications to help lower your cat’s blood pressure, your veterinarian will need to run lab tests to detect any underlying diseases that contribute to hypertension. 

This typically includes blood work and urine testing. 

Pet parents do typically notice an improvement in their cat’s demeanor and energy levels after starting therapy for hypertension. However, if your cat had vision loss at the time of diagnosis, it may be a permanent consequence of hypertension. 

Since hypertension is often unnoticeable until it has been present long enough to cause significant organ damage, the International Society of Feline Medicine (ISFM) recommends routine blood pressure screening for cats as follows: 

• Healthy senior cats (7–10 years of age): every 12 months 

• Healthy geriatric cats (11+ years of age): every six to 12 months 

• Cats with CKD, hypertension, or other diseases that increase the risk of hypertension, as well as those with signs of hypertensive organ damage: at time of diagnosis, and then every three to six months 

Hypertension in Cats Prognosis

The prognosis for cats diagnosed with hypertension is good with regular treatment.  

Remember, blood pressure is managed rather than cured. Your cat will need regular checkups to ensure they’re on the correct dosage.