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Prazosin for Cats

By | Last Updated: 22nd February 2023

What is prazosin

Prazosin is an oral medication used for managing high blood pressure [15].

Can cats use prazosin

Prazosin is commonly used for the treatment of high blood pressure, hypertension, congestive heart failure [1], FIC (feline idiopathic cystitis) [12], and conditions associated with FLUTD (feline lower urinary tract disease) [12] like urethral blockage [2, 3], spasm, or infections. Since it helps in controlling intraurethral intraluminal pressure, it is beneficial for lessening the symptoms of urolithiasis, ureterolithiasis, and prostatic hyperplasia [4].

Although phenoxybenzamine, an alpha-blocker, has been the preferred choice of drug used for treating urethral obstruction in pets, it has now been replaced by prazosin because of its selective alpha-1 receptor blocking activity [4].

Quick Information

Prazosin for Cats

Generic name: Prazosin

Brand name: Minipress [3]

Type: Alpha-1 adrenergic blocker [5]

Active Ingredients: Prazosin hydrochloride [3]

Is it approved by FDA: No [5]

Availability: Compounded by specialty pharmacies [1]

Who can take it: Cats, dogs, humans [1]

Forms: 1mg and 2mg capsules [3]

Cost: About $0.8 (per 1mg capsule)

How does prazosin work in your cat

Prazosin inhibits the effect of nerve impulses on blood vessels by particularly binding to the alpha-1-adrenergic receptors of the smooth muscle [13, 14]. It lessens any resistance to the blood flow, thus reducing venous and arterial pressure, increasing cardiac output without causing any adverse effects on the sympathetic nervous system [5]. Therefore, it ensures free circulation of blood and oxygen around your cat’s body, which in turn, reduces strain on its heart [13]. It also helps in relaxing the smooth muscles of the internal urethral sphincter, thereby reducing spasm associated with feline urethral obstruction [5].

Prazosin dosage for cats: How much can be given

Talk to your cat’s vet to make sure that you get the dose right. The usually recommended dosage is 0.25 to 1.0 mg, given orally with food (or flavored food) at an interval of 8-12 hours a day [1, 6]. Always wash your hands after handling the medication [1].

It usually starts working within a few hours of giving the first dose; but in some cases, the effects may not become obvious before a few more doses.

What to do if you miss giving a dose

If a dose of prazosin is missed, try to get back on track as early as possible. However, if it is time for the next regular dose, it is best that you skip the missed dose and continue with the scheduled one. It is advisable to avoid giving a double dose [7].

Prazosin overdose symptoms

  • Decreased reflexes [5]
  • Drowsiness [5]
  • Tachycardia (your cat is coughing, and exhibiting physical weakness with abnormal breathing, or fainting) [5, 8]

If your cat shows any of these signs, immediately call your vet or the ASPCA’s Poison Control Center at 1-888-426-4435.

Prazosin side effects in cats

The side effects might occur when you first start to give the medicine [1]. Common side effects may include:

  • Lethargy [5]
  • Nausea [5]
  • Diarrhea (your cat is having fever, decreased appetite, showing increased urgency to eliminate, losing weight) [5, 11]
  • Vomiting [5]
  • Constipation (the cat is straining to eliminate, discharging mucous or blood with small, hard, dry stools, showing less interest in food) [5, 10]

Some of the serious side effects, which may occur with its long-term use, include dizziness or loss of consciousness [5, 9].

Contact your vet if your cat shows any of these symptoms while taking this medicine.

When should you not give prazosin to cats

Make sure that you inform the veterinarian about the medications you are already giving your cat for any pre-existing health conditions. Prazosin should not be administered to cats:

  • With chronic kidney diseases or low blood pressure [5, 9]
  • That are pregnant or breastfeeding [5]
  • Already on beta blockers, nifedipine, verapamil, sildenafil, and clonidine [5]


    1. Prazosin For Dogs And Cats – Wedgewoodpetrx.com
    2. Initial treatment factors associated with feline urethral obstruction occurrence rate: 192 cases (2004-2010) – Ncbi.nlm.nih.gov
    3. Prazosin Hydrochloride – Vetrxdirect.com
    4. Prazosin – Vetbook.org
    5. Prazosin For Veterinary Use – Wedgewoodpetrx.com
    6. Feline Lower Urinary Tract Disease – Vin.com
    7. Prazosin – Albertcottagevets.com
    8. Rapid Heart Beat in Cats – Petmd.com
    9. Prazosin Compounded – 1800petmeds.com
    10. Constipation in Cats: Symptoms and Treatment – Pets.webmd.com
    11. Diarrhea Causes and Treatments for Cats – Pets.webmd.com
    12. Diagnosing and managing idiopathic cystitis in cats (Proceedings) – Vetrinarycalendar.dvm360.com
    13. Prazosin – an alpha-blocker – Patient.info
    14. Alpha-Adrenoceptor Antagonists (Alpha-Blockers) – Cvpharmacology.com
    15. Prazosin, Oral Capsule – Healthline.com

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