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Tamsulosin

Prescription
Selective Alpha-1A Adrenergic Antagonist
Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
1 available
Formulations
1

Mechanism of action

Selectively blocks alpha-1A adrenergic receptors concentrated in the prostate, bladder neck, and urethra, relaxing smooth muscle and reducing urethral resistance. More uroselective than prazosin (less systemic hypotension).

At a glance

Class
Selective Alpha-1A Adrenergic Antagonist
Schedule
Prescription
Storage
Store at room temperature below 25°C

Dosing

🐕

Dog

Off-label for functional urethral obstruction, benign prostatic hyperplasia, and
Dose
0.01–0.05 mg/kg
Route
PO
Frequency
q24h
🐈

Cat

Off-label for post-obstructive urethral spasm
Dose
0.004–0.01 mg/kg
Route
PO
Frequency
q24h

Formulations

💊

Other — 1

Strength

Storage

Store at room temperature below 25°C

Safety

Monitoring parameters

Blood pressureUrine streamClinical response (urination frequency, straining)

Interactions

No documented interactions.

Brands

Other markets

Flomax

FAQs

Frequently asked questions

What is Tamsulosin?
Tamsulosin is a selective alpha-1a adrenergic antagonist used in pets. Selectively blocks alpha-1A adrenergic receptors concentrated in the prostate, bladder neck, and urethra, relaxing smooth muscle and reducing urethral resistance. More uroselective than prazosin (less systemic hypotension).
What is Tamsulosin used for in pets?
Tamsulosin is used in veterinary medicine for: Off-label for functional urethral obstruction, benign prostatic hyperplasia, and; Off-label for post-obstructive urethral spasm.
What is the Tamsulosin dose for dogs?
For dogs, Tamsulosin is typically dosed as follows — Off-label for functional urethral obstruction, benign prostatic hyperplasia, and: 0.01–0.05 mg/kg PO q24h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
What is the Tamsulosin dose for cats?
For cats, Tamsulosin is typically dosed as follows — Off-label for post-obstructive urethral spasm: 0.004–0.01 mg/kg PO q24h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
Does Tamsulosin need a prescription?
Yes. Tamsulosin is a prescription medication and should only be administered under veterinary supervision.

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 →