High Blood Pressure in Cats: Hypertension Signs, Causes and Treatment

By Tailwisp Editorial TeamUpdated October 20, 20264 min read

High blood pressure is sometimes called the silent killer in people. In cats, it can be just as quiet, until a sudden problem, such as blindness, brings the cat to the vet. Knowing who is at risk, and checking regularly, can prevent lasting harm.

What is hypertension in cats?

Blood pressure is the force of blood against vessel walls. When it stays too high, it damages delicate organs with many small vessels: the eyes, brain, kidneys and heart. This is called target organ damage. Systolic pressure over about 160 mmHg is usually considered high, and over 180 mmHg is severe, with high risk of damage.

Causes

Most feline hypertension is secondary to another disease:

• Chronic kidney disease. A leading cause. See chronic kidney disease in cats.
• Hyperthyroidism. See hyperthyroidism in cats.
• Diabetes, in some cats. See diabetes in cats.
• Heart disease.
• Adrenal tumors, a rarer cause.
• Primary (idiopathic) hypertension, with no cause found, which is less common than in people.
• Stress at the vet, which can raise readings temporarily. This is called white coat hypertension.

Who should be screened

Vets recommend regular blood pressure checks for cats over about seven years, cats with kidney disease, hyperthyroidism or heart disease, and those with eye problems or neurological signs. Many clinics include it in senior wellness exams. See cat wellness exam: what to expect and senior cat care guide.

Signs

Many cats have no obvious signs. When signs appear, they reflect organ damage:

• Eyes: sudden blindness, dilated pupils, bleeding in the eye, retinal detachment, a cloudy eye. See cat eye problems and cat glaucoma.
• Brain: disorientation, circling, head pressing, seizures, wobbliness, behavior change. See seizures in cats.
• Kidneys: worsening kidney disease, protein in urine.
• Heart: a murmur, enlarged heart, breathing difficulty. See congestive heart failure in cats.
• Nosebleeds.
• Increased vocalizing and restlessness.

Sudden blindness is an emergency. Quick treatment may restore some vision.

How blood pressure is measured

A small cuff is placed on a leg or the tail, and a Doppler or oscillometric device reads the pressure. The vet usually takes several readings in a calm room, sometimes with the owner present, to reduce stress effects. A single high reading in a nervous cat may be repeated. If readings are high, vets run tests to find the cause and check for organ damage, including bloodwork, urine tests, thyroid tests, an eye exam and sometimes an echocardiogram.

Treatment

• Amlodipine. A calcium channel blocker, given by mouth, once daily, is the first-choice drug for most cats. It usually lowers pressure within days. See how to give a cat a pill.
• Other drugs, such as telmisartan, may be added.
• Treat the cause, such as thyroid disease or kidney disease.
• Diet, as advised for kidney disease.
• Rechecks. Blood pressure, eyes and kidney values are monitored every few weeks at first, then every few months.

Medication is usually lifelong, and doses may change.

Home care

• Give medication on time, every day.
• Keep appointments for rechecks.
• Watch for changes in vision, behavior or appetite.
• Keep stress low, and avoid sudden changes.
• Keep a low-stress carrier routine for visits. See helping a cat who hates the vet.

Outlook

With treatment, many cats do very well. The outlook depends on the underlying disease and the extent of organ damage at diagnosis. Early detection preserves sight and kidney function.

Why home and clinic readings differ

A cat's blood pressure can rise from stress alone, particularly in a clinic, which is why vets wait for the cat to settle, use a quiet room and repeat the reading. Some clinics let owners stay in the room and use a mat or a familiar blanket. If your cat gets very worked up, ask about a different appointment time, or a visit with minimal waiting. A single high reading without other signs may not prompt treatment, but should be followed up.

Eye emergencies

Sudden loss of vision or bleeding in the eyes can be the first sign of hypertension. If you notice dilated pupils that do not respond to light, a cat that bumps into furniture, or blood visible in the eye, call the vet at once. Treating the blood pressure quickly gives the best chance that the retina will reattach and vision will return, and prevents further damage.

Kidneys and blood pressure

The kidneys and blood pressure affect each other. High pressure damages kidney tissue, and failing kidneys raise pressure. Controlling pressure can slow the decline of kidney function in cats with kidney disease. Your vet may also check protein in the urine, since protein loss is a sign of kidney stress.

Monitoring for life

Even when pressure is controlled, regular checks are needed, because the dose may need to change as disease progresses. Expect rechecks every three to six months for cats on treatment, and more often at the start. Never stop or change the dose without talking to your vet.

When to see a vet

See a vet immediately for sudden blindness or seizures, and schedule a pressure check for seniors. Use the US vet directory to find a clinic.

This article is general educational information, not veterinary advice. Every cat is different. If your cat is unwell, or you are unsure about a symptom, diet change or medication, contact your veterinarian.