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Phenylpropanolamine

Prescription
Alpha-adrenergic agonist / Sympathomimetic
Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
3 available
Interactions
2 documented
Formulations
4

Mechanism of action

Stimulates alpha-1 adrenergic receptors in the urethral smooth muscle, increasing urethral sphincter tone and improving urinary continence; also has mild beta-adrenergic activity

At a glance

Class
Alpha-adrenergic agonist / Sympathomimetic
Schedule
Prescription
Storage
Below 25°C

Dosing

🐕

Dog

Urethral sphincter mechanism incompetence (urinary incontinence)
Dose
1–2 mg/kg
Route
PO
Frequency
BID to TID
Max dose
75 mg/dose; 225 mg/day
Duration: Long-term / lifelong
🐈

Cat

Urinary incontinence (less common)
Dose
1–1.5 mg/kg
Route
PO
Frequency
BID to TID
Max dose
12.5 mg/dose; 37.5 mg/day
Duration: Long-term as needed

Formulations

💊

Chewable tablet — 3

Strength
25mg
Strength
50mg
Strength
75mg
🧴

Oral syrup — 1

Strength
40mg/mL

Storage

Below 25°C

Safety

Absolute contraindications — do not use

  • Uncontrolled hypertension
    Sympathomimetic effect raises blood pressure

Use with caution

  • Cardiac disease, glaucoma, hyperthyroidism
    May potentiate sympathomimetic effects

Adverse effects

Common
Restlessness
Decreased appetite
Mild hypertension
Serious
Severe hypertension
Tachycardia
Stroke (rare in dogs)

Monitoring parameters

Blood pressureHeart rateContinence statusAppetite

Interactions

Contraindicated — 1

Selegiline (L-Deprenyl)
contraindicated
PPA releases norepinephrine + MAO inhibitor prevents catecholamine breakdown: hypertensive crisis.
Management: NEVER combine. Use alternative urinary incontinence therapy (estriol, DES) with selegiline.

Moderate — 1

Atenolol
moderate
PPA (alpha/beta agonist) + beta-blocker: unopposed alpha vasoconstriction. Blood pressure elevation.
Management: Monitor blood pressure closely when combining. Use lowest effective PPA dose.

Brands

International

Proin
PRN Pharmacal
Propalin
Vetoquinol

India

PPA Syrup (compounded)
Various

FAQs

Frequently asked questions

›What is Phenylpropanolamine?
Phenylpropanolamine is a alpha-adrenergic agonist / sympathomimetic used in pets. Stimulates alpha-1 adrenergic receptors in the urethral smooth muscle, increasing urethral sphincter tone and improving urinary continence; also has mild beta-adrenergic activity
›What is Phenylpropanolamine used for in pets?
Phenylpropanolamine is used in veterinary medicine for: Urethral sphincter mechanism incompetence (urinary incontinence); Urinary incontinence (less common).
›What is the Phenylpropanolamine dose for dogs?
For dogs, Phenylpropanolamine is typically dosed as follows — Urethral sphincter mechanism incompetence (urinary incontinence): 1–2 mg/kg PO BID to TID. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Phenylpropanolamine dose for cats?
For cats, Phenylpropanolamine is typically dosed as follows — Urinary incontinence (less common): 1–1.5 mg/kg 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 Phenylpropanolamine?
Common: Restlessness, Decreased appetite, Mild hypertension. Serious (call your vet immediately): Severe hypertension, Tachycardia, Stroke (rare in dogs).
›Does Phenylpropanolamine need a prescription?
Yes. Phenylpropanolamine is a prescription medication and should only be administered under veterinary supervision.
›When should Phenylpropanolamine not be used?
Do not use Phenylpropanolamine if: Uncontrolled hypertension.

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 →