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Prazosin

Prescription
Alpha-1 adrenergic blocker (selective)
Last reviewed 19 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
3 available
Interactions
1 documented
Formulations
3

Mechanism of action

Selectively blocks alpha-1 adrenergic receptors, relaxing urethral and prostatic smooth muscle; also reduces systemic vascular resistance

At a glance

Class
Alpha-1 adrenergic blocker (selective)
Schedule
Prescription
Storage
Store below 25°C, protect from light

Dosing

🐕

Dog

Urethral sphincter hypertonus / Functional urinary retention
Dose
0.5–2 mg per dog
Route
PO
Frequency
BID to TID
Max dose
5 mg/dose; 15 mg/day
Duration: As needed
🐈

Cat

Feline urethral obstruction (post-unblocking) / FLUTD
Dose
0.25–0.5 mg per cat
Route
PO
Frequency
BID to TID
Max dose
1 mg/dose; 3 mg/day
Duration: 5–14 days post-catheter removal

Formulations

💊

Tablet — 2

Strength
1mg
Available in India
Strength
2mg
Available in India
💊

Capsule — 1

Strength
1mg
Available in India

Storage

Store below 25°C, protect from light

Safety

Absolute contraindications — do not use

  • Hypotension

Use with caution

  • Renal impairment

Adverse effects

Common
Hypotension (first-dose effect)
Lethargy
Serious
Syncope
Severe hypotension

Monitoring parameters

Blood pressureUrination frequency/volume

Interactions

Moderate — 1

Amlodipine
moderate
Additive hypotensive effect — both are vasodilators acting through different mechanisms
Management: Start prazosin at lowest dose if patient is on amlodipine. Monitor blood pressure closely.

Brands

International

Minipress
Pfizer

India

Prazopress
Sun Pharma
Prazocip
Cipla

FAQs

Frequently asked questions

›What is Prazosin?
Prazosin is a alpha-1 adrenergic blocker (selective) used in pets. Selectively blocks alpha-1 adrenergic receptors, relaxing urethral and prostatic smooth muscle; also reduces systemic vascular resistance
›What is Prazosin used for in pets?
Prazosin is used in veterinary medicine for: Urethral sphincter hypertonus / Functional urinary retention; Feline urethral obstruction (post-unblocking) / FLUTD.
›What is the Prazosin dose for dogs?
For dogs, Prazosin is typically dosed as follows — Urethral sphincter hypertonus / Functional urinary retention: 0.5–2 mg per dog PO BID to TID. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Prazosin dose for cats?
For cats, Prazosin is typically dosed as follows — Feline urethral obstruction (post-unblocking) / FLUTD: 0.25–0.5 mg per cat PO BID to TID. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What are the side effects of Prazosin?
Common: Hypotension (first-dose effect), Lethargy. Serious (call your vet immediately): Syncope, Severe hypotension.
›Does Prazosin need a prescription?
Yes. Prazosin is a prescription medication and should only be administered under veterinary supervision.
›When should Prazosin not be used?
Do not use Prazosin if: Hypotension.

References

References

Textbooks & handbooks

  • Plumb, D.C. Plumb's Veterinary Drug Handbook. 10th ed., Wiley-Blackwell, 2023.
  • Vail, D.M., Thamm, D.H., & Liptak, J.M. (eds.). Withrow & MacEwen's Small Animal Clinical Oncology. 6th ed., Saunders/Elsevier, 2020.
  • Riviere, J.E., & Papich, M.G. (eds.). Veterinary Pharmacology and Therapeutics. 10th ed., Wiley-Blackwell, 2018.
  • National Research Council. Nutrient Requirements of Dogs and Cats. National Academies Press, Washington DC, 2006.
  • The Merck Veterinary Manual. Merck & Co., Online edition. https://www.merckvetmanual.com/

Clinical guidelines & consensus

  • Fletcher, D.J., Boller, M., Brainard, B.M., et al. "RECOVER Evidence and Knowledge Gap Analysis on Veterinary CPR." Journal of Veterinary Emergency and Critical Care, 2012;22(S1):S102–S131.
  • American Animal Hospital Association. 2018 AAHA Diabetes Management Guidelines for Dogs and Cats. AAHA Press.

Journals & peer-reviewed studies

  • Hogan, D.F., Fox, P.R., Jacob, K., et al. "Secondary prevention of cardiogenic arterial thromboembolism in the cat: The FAT CAT study." Journal of Veterinary Cardiology, 2015;17(Suppl 1):S306–S317.
  • Boswood, A., Häggström, J., Gordon, S.G., et al. "Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study — A Randomized Clinical Trial." Journal of Veterinary Internal Medicine, 2016;30(6):1765–1779.
  • ASPCA Animal Poison Control Center. Toxicology and Poison Management Guidelines. American Society for the Prevention of Cruelty to Animals. https://www.aspca.org/pet-care/animal-poison-control

Regulatory & approvals

  • Central Drugs Standard Control Organisation (CDSCO), Government of India. Veterinary Drug Approval Registry, 1969–2026. Directorate General of Health Services. https://cdsco.gov.in/

Databases

  • Washington State University, College of Veterinary Medicine. Veterinary Clinical Pharmacology Laboratory (VCPL) — MDR1 Multidrug Sensitivity Database. https://vcpl.vetmed.wsu.edu/
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →