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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
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 →

Formulations

💊

Other — 1

Strength

Storage

Store at room temperature below 25°C

Safety

Monitoring parameters

Blood pressureUrine streamClinical response (urination frequency, straining)
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 →

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.
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 →

References

References

The PetCare.AI drug reference is built from 13 authoritative sources cited across 580 drug monographs.

Textbooks & handbooks — 5

  • Plumb's Veterinary Drug Handbook
  • Withrow & MacEwen's Small Animal Clinical Oncology
  • Merck Veterinary Manual
  • NRC Nutrient Requirements of Dogs and Cats
  • Veterinary Pharmacology and Therapeutics (Riviere & Papich)

Clinical guidelines & consensus — 4

  • ASPCA Animal Poison Control Center Guidelines
  • AAHA Diabetes Management Guidelines
  • ASPCA Poison Control Guidelines
  • RECOVER CPR Guidelines

Journals & peer-reviewed studies — 2

  • EPIC Study (J Vet Intern Med 2016)
  • JVIM FAT CAT Study

Regulatory & approvals — 1

  • CDSCO Veterinary Drug Approval Registry (1969–2026)

Databases — 1

  • Washington State University VCPL MDR1 Database
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