# 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.

Source: https://vetmasterji.com/drugs/phenylpropanolamine · Last reviewed: 2026-10-01

## 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

> **Caution:** 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.

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## 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?

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

### What are the side effects of Phenylpropanolamine (PPA) in animals?

Hypertension; Restlessness, anxiety, aggression; Anorexia; Tachycardia.

## Sources

- Plumb's Veterinary Drug Handbook
- Papich 5e — Phenylpropanolamine Hydrochloride
- Papich, Papich Handbook of Veterinary Drugs, 5th edition

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VetMasterJi is a clinical decision-support and education platform for veterinary professionals and students. It does not provide veterinary advice, diagnosis or treatment for specific animals. All drug doses, calculators and differentials are references that must be independently verified before clinical use; the attending registered veterinarian remains solely responsible for every clinical decision.