Quick answer
Urinary blockage in male cats is an emergency. A plug of crystals and mucus, a stone or a spasm closes the narrow urethra so urine can't get out, and a completely blocked cat can die within 2 to 3 days without treatment. If your male cat is straining to pee and little or nothing comes out, take him to a vet or emergency clinic now, day or night.
Don’t wait until morning and don’t try home remedies. Call ahead so the clinic can get ready, and see our cat emergency page for what to bring.
What is a urinary blockage in male cats?
A urinary blockage (urethral obstruction) happens when something closes the urethra, the tube that carries urine from the bladder out of the body. Male cats have a long, narrow urethra, so they’re at much higher risk than females. Neutered males are no exception.
Once urine can’t get out, the bladder swells and waste and potassium build up in the blood. According to the Merck Veterinary Manual, a complete blockage leads to kidney failure within 36 to 48 hours and can cause death in about 72 hours. High potassium can stop the heart even sooner.
Vets often call an affected cat a “blocked cat” or “blocked tom.” It’s one of the most common true emergencies in cats.
What are the signs of a blocked cat?
The first sign is usually a cat straining to pee. Owners often mistake it for constipation, which costs precious hours.
| Sign | What it means | Urgency |
|---|---|---|
| Frequent trips to the box, tiny or no clumps | Urine can’t pass | Emergency |
| Crying, licking genitals, restless | Painful, overfull bladder | Emergency |
| Vomiting, not eating, hiding | Toxins building up in the blood | Emergency |
| Weak, collapsed, cold to the touch | High potassium affecting the heart | Emergency |
| Peeing small amounts often, some blood, still producing clumps | Cystitis without full blockage | See vet soon |
Even partial blockages can become complete within hours. If you see blood in your cat’s urine along with straining, have him seen the same day.
What causes a urinary blockage?
Most blockages come from bladder inflammation. The three main causes are:
- Urethral plugs: a paste of mucus, cells and crystals (often struvite). The Merck Veterinary Manual lists plugs as the cause in most blocked male cats.
- Bladder or urethral stones: small stones can lodge in the urethra.
- Spasm and swelling: from feline idiopathic cystitis, a stress-linked bladder inflammation, which can squeeze the urethra closed.
Risk goes up with dry-food-only diets, low water intake, being overweight, indoor living with little activity and stress, such as a new pet, a move or litter box problems. A bacterial cat UTI is a less common trigger in young cats.
How do vets treat a blocked cat?
Treatment starts as soon as you arrive. Your vet will first stabilize your cat, then relieve the blockage.
- Blood tests and heart check: to measure potassium and kidney values and watch for a dangerous heart rhythm.
- IV fluids and medicines: to correct potassium, flush waste and control pain.
- Unblocking: under sedation or general anesthesia, the vet passes a thin catheter into the urethra to clear the plug and empty the bladder.
- Hospital stay: the catheter is usually left in for a day or more while IV fluids flush the bladder and the kidneys recover. Most cats stay in the hospital for 2 to 4 days.
- Going home: usually with pain relief, sometimes other medicines, and a plan to increase water intake. Your vet will set every dose.
Watch him closely for the first few weeks at home. Blockages come back in a significant number of cats, most often in the first days to weeks. If he strains again, go back right away.
What is PU surgery?
For cats that block again and again, or can’t be unblocked with a catheter, vets may recommend a perineal urethrostomy (PU). This surgery removes the narrowest part of the urethra and makes a wider opening, which greatly lowers the risk of another blockage. It doesn’t stop cystitis itself, so diet and stress care still matter.
How much does it cost to treat a urinary blockage?
Blocked cats are almost always treated at an emergency clinic or through a hospital stay, so costs are high. These are typical US ranges.
| Treatment | Typical cost |
|---|---|
| Emergency exam | $100 – $250 |
| Unblocking, catheter and 2–4 day hospital stay | $1,500 – $4,000 |
| Emergency clinic or complicated case | $3,000 – $6,000 |
| PU surgery | $2,000 – $5,000 |
For a full breakdown, see cat urinary blockage surgery cost and emergency vet costs for cats.
How can I prevent my cat from getting blocked again?
Prevention focuses on dilute urine and a calm cat. Your vet may recommend:
- A prescription urinary diet, especially if crystals or stones were found. Use it long term if your vet advises.
- More water: wet food, water fountains, several bowls around the house and adding water to meals.
- Weight control and play to keep him active.
- Less stress: a steady routine, hiding spots, vertical space and one more litter box than you have cats, kept clean.
- Regular urine checks after a blockage.
If you’re ever unsure whether straining is urgent, use our should I take my cat to the vet? checker, or just go. For other bladder and kidney problems, browse our cat health problems guides.
Frequently asked questions
Can a female cat get a urinary blockage?
It's possible but rare. Female cats have a shorter, wider urethra, so blockages happen almost only in males. Any cat straining without producing urine still needs a vet right away.
Can a blocked cat pass urine on his own?
Occasionally a plug moves and a cat passes some urine, but the blockage often returns within hours. Even if he seems better, he still needs to be checked by a vet the same day.
Is my cat constipated or blocked?
The two look alike, since both cats strain in the box. Check for urine clumps. If there are none or only tiny ones, assume a blockage and go to a vet now.
Sources
Written by the CatsMed Team from the sources above. This guide isn’t reviewed by a veterinarian and isn’t a substitute for one. See how we research.
