Feline systemic hypertension is high blood pressure in cats, usually secondary to chronic kidney disease, hyperthyroidism, or both. Most cats show no symptoms until the pressure damages the eyes, brain, or kidneys. The ACVIM consensus on hypertension recommends annual blood pressure screening starting at age 7 to catch it before vision loss.
Last reviewed: May 2026
What Counts as High Blood Pressure in a Cat
Normal cat systolic blood pressure is 120 to 140 mmHg. The 2018 ACVIM consensus defines hypertension by risk of organ damage: less than 140 normotensive, 140 to 159 prehypertensive, 160 to 179 hypertensive, and over 180 severely hypertensive. About 65 percent of cats with chronic kidney disease and 20 to 25 percent of cats with hyperthyroidism are hypertensive at some point in the disease course (Acierno et al., 2018, JVIM).
Why It Is Called the Silent Killer
Most hypertensive cats look completely normal until target organ damage appears. The first noticed sign is often sudden blindness — owners describe a cat who walks into walls, has dilated pupils that do not constrict in bright light, or bumps into furniture in familiar rooms. By the time vision is gone, the retinas have already detached or hemorrhaged. Less obvious early signs include subtle disorientation, increased nighttime vocalization, weight loss, or worsening of underlying kidney disease.
Common Symptoms by Target Organ
Eyes: sudden blindness, dilated pupils, blood inside the eye (hyphema), retinal detachment visible as a darker red spot on the back of the eye on exam. Brain: seizures, head pressing, ataxia, behavioral change, sudden vocalization. Kidneys: accelerated decline in kidney function, more dilute urine, faster progression through IRIS CKD stages. Heart: a new murmur, gallop rhythm, or thickened left ventricle on echocardiogram. Roughly 50 percent of cats presenting with hypertensive crisis have eye findings, and many have multiple organs involved.
Causes — Mostly Secondary
About 80 to 85 percent of feline hypertension is secondary to another disease — chronic kidney disease leads, followed by hyperthyroidism, and less commonly hyperaldosteronism, Cushing's disease, or pheochromocytoma. Idiopathic (primary) hypertension accounts for the remaining 15 to 20 percent and is more common in older cats with no other identifiable disease. The AAFP Senior Care Guidelines, 2021 recommend annual BP measurement in all cats over 7 years, with twice-yearly checks once any underlying disease is found.
How Cats Get Their Blood Pressure Taken
Cat BP is taken with a Doppler ultrasound or oscillometric machine, with a cuff on a front leg or the tail. Cats need 5 to 10 minutes to settle in a quiet room first; "white coat hypertension" from stress can elevate readings by 20 to 40 mmHg. The standard is to take 5 to 7 readings, discard the first, and average the rest. A persistently elevated reading on two visits — or a single very high reading with target organ damage — confirms the diagnosis.
Treatment
The treatment goal is to bring systolic pressure below 160 mmHg, ideally between 120 and 140. Amlodipine besylate is the first-line drug in cats — given once daily as a small oral tablet — and brings most cats under control within 1 to 2 weeks. Cats with proteinuria from CKD may also receive an ACE inhibitor or telmisartan. Treating the underlying cause (managing CKD or treating hyperthyroidism) often improves but does not always normalize the BP. Monitoring is monthly until controlled, then every 3 to 6 months.
When to See a Vet
Call your vet today if:
- Sudden behavior change in a cat over 10 years old
- Pupils that appear dilated even in bright light
- Walking into furniture or appearing disoriented
- New onset nighttime vocalization or aggression
- Worsening of known kidney disease or hyperthyroidism
Go to the ER immediately if:
- Sudden blindness, even if your cat seems otherwise okay
- Seizures or collapse
- Visible blood inside the eye
- Severe lethargy plus rapid breathing in a cat with kidney disease
- Acute head tilt, circling, or unsteady walking
What's going on with your pet?
Describe symptoms or snap a photo. Voyage tells you urgency, home care, and whether you need a vet.
First, tell us about your pet
Breed and age make a real difference in how Voyage interprets symptoms.
Describe the symptoms
🏆 Outperforms ChatGPT & Gemini · 🩺 Vet-grounded · 🔒 Private
Love it? See everything Voyage can do
Frequently Asked Questions
How much does cat hypertension treatment cost?
Blood pressure measurement as part of a senior wellness visit runs $50 to $100. The full workup — exam, BP, bloodwork, urinalysis, T4 thyroid test — typically costs $250 to $500. Amlodipine, the most common medication, is inexpensive at $15 to $40 per month. If retinal detachment requires referral to a veterinary ophthalmologist for evaluation, expect $300 to $600 for that consultation.
Can my cat get her vision back after a retinal detachment?
Sometimes. If hypertension is identified within 1 to 3 days of detachment and blood pressure is brought under control quickly, partial or even full vision can return in roughly 50 percent of cats. After about 1 to 2 weeks of detachment, permanent blindness becomes likely. This is why sudden blindness in a senior cat is a same-day emergency, not something to monitor over the weekend.
Can stress alone cause high readings?
Yes — "white coat hypertension" can raise a cat's BP by 20 to 40 mmHg. That is why vets take multiple readings after letting the cat acclimate for 5 to 10 minutes in a quiet room, and why a diagnosis is usually based on consistent elevation across multiple visits — not a single high number.
How often should I screen my senior cat?
The AAFP recommends annual blood pressure screening starting at age 7 in healthy cats. Once a cat is diagnosed with chronic kidney disease, hyperthyroidism, or any condition that increases hypertension risk, BP should be checked every 3 to 6 months, even if previous readings were normal.
Will amlodipine make my cat feel different?
Most cats show no behavioral change on amlodipine. A small percentage develop gum overgrowth (gingival hyperplasia) after months on the drug. Side effects are uncommon and usually mild. Owners often notice the cat is brighter and more active within 1 to 2 weeks because the headache and pressure on the eyes resolve.
Still Not Sure if Your Cat Needs a Vet?
When you're not sure if this is wait-and-see or call-tonight, Voyage AI Vet triages in under 2 minutes. Describe what you're seeing in chat, share photos of your cat's eyes (especially if pupils look unusually dilated), any disorientation, or unusual bumping into furniture, or hop on a live video call if you want a second pair of eyes. Every answer comes with citations to the actual veterinary literature it's pulling from — so you see exactly where the guidance comes from, not just a chatbot's word.