Veterinary drug · Drug monograph

Phenylpropanolamine (PPA): veterinary dose and monograph

Phenylpropanolamine (PPA) is a veterinary drug. Sympathomimetic (alpha-adrenergic) that increases urethral sphincter tone — first-line treatment for urethral sphincter mechanism incompetence in spayed bitches; often combined with oestriol. Indications include urethral sphincter mechanism incompetence (spayed bitches); urethral sphincter hypotonus in cats; retrograde ejaculation (dogs). This monograph lists 4 reference doses for dogs and cats, each with route, frequency and source.

At a glance

Drug class: Veterinary drug
Also known as: PPA, Proin, Propalin, Cystolamine
Species with doses: Dogs and Cats
General dose range: 1–2 mg/kg PO q8–12h — check the species tables for the indication
Routes: PO
Last reviewed: 1 October 2026

Indications

Urethral sphincter mechanism incompetence (spayed bitches)
Urethral sphincter hypotonus in cats
Retrograde ejaculation (dogs)

Phenylpropanolamine (PPA) dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

Phenylpropanolamine (PPA) doses for dogs
Indication	Dose	Route	Frequency	Duration
Urethral sphincter incompetence (immediate-release)	1–2 mg/kg	PO	q8–12h (may reduce to q12–24h)	—
Urethral sphincter incompetence (extended-release)	2–4 mg/kg	PO	q24h	—
Retrograde ejaculation	3–4 mg/kg	PO	q12h	—

Urethral sphincter incompetence (immediate-release): Papich 5e: 1 mg/kg q8h, increasing to 1.5–2 mg/kg q8h if needed; some dogs can drop to q12h or q24h. Plumb’s p.968: 1–2 mg/kg (or 12.5–50 mg per dog) q8h (Bartges); 1–1.5 mg/kg two to three times daily controls 74–92% of dogs (Chew); 1.5 mg/kg q8–12h (Vernau). Monitor blood pressure.
Urethral sphincter incompetence (extended-release): Papich 5e: ER formulation 2–4 mg/kg once daily. Plumb’s p.968 (75 mg time-release label): <40 lb ½ capsule, 40–100 lb 1 capsule, >100 lb 1½ capsules daily.
Retrograde ejaculation: Plumb’s p.968 (Fontbonne 2007): 3–4 mg/kg PO twice daily may be tried.

Cats

Phenylpropanolamine (PPA) doses for cats
Indication	Dose	Route	Frequency	Duration
Urethral sphincter hypotonus	1–2.2 mg/kg	PO	q8–12h	—

Urethral sphincter hypotonus: Plumb’s p.968: 1–1.5 mg/kg q8h (Bartges); 1.1–2.2 mg/kg two to three times daily (Lane); 12.5 mg per cat q8h. Papich 5e: no established cat dose — 1 mg/kg q12h has been used by extrapolation.

Contraindications

Hypertension, cardiac disease or arrhythmias, glaucoma, hyperthyroidism, diabetes mellitus, advanced renal disease. Avoid with MAO inhibitors (selegiline, amitraz) and other sympathomimetics.

Adverse effects

Hypertension
Restlessness, anxiety, aggression
Anorexia
Tachycardia

Monitoring

Blood pressure before and during treatment
Continence response
Behaviour changes

Formulations and products

Chewable tablet 25 / 50 / 75 mg
Oral solution 25 mg/mL
Oral solution 50 mg/mL
Timed-release capsule 75 mg

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Frequently asked questions

What is the dose of Phenylpropanolamine (PPA) for dogs?

Reference doses for Phenylpropanolamine (PPA) in dogs: 1–2 mg/kg PO q8–12h (may reduce to q12–24h) (Urethral sphincter incompetence (immediate-release)); 2–4 mg/kg PO q24h (Urethral sphincter incompetence (extended-release)); 3–4 mg/kg PO q12h (Retrograde ejaculation). Confirm against the label and the patient before use.

What is the dose of Phenylpropanolamine (PPA) for cats?

Reference doses for Phenylpropanolamine (PPA) in cats: 1–2.2 mg/kg PO q8–12h (Urethral sphincter hypotonus). Confirm against the label and the patient before use.

When should Phenylpropanolamine (PPA) not be used?