Phenylpropanolamine (Proin) for Dogs in 2025 🐶

Urinary incontinence—leaking urine during rest or sleep—is common in spayed female dogs and some male dogs. Thankfully, phenylpropanolamine (Proin®) remains one of the most effective medications to treat it. I’m Dr Duncan Houston BVSc, and in this 2025 guide, I’ll explain how Proin works, when to use it, and what side effects to watch for 🐾💊

💧 What Is Proin (Phenylpropanolamine)?

Phenylpropanolamine is a sympathomimetic agent that tightens the bladder sphincter by stimulating the autonomic nervous system—similar to a mild stimulant. It helps stop urine leakage by increasing tone in the urethra.

📦 Available Forms

• 💊 Regular chewable tablets: 25 mg, 50 mg, 75 mg (given twice daily)
• 💊 Extended-release tablets: 18 mg, 38 mg, 74 mg, 145 mg (given once daily)

🩺 How It’s Used

• ⏱️ Standard tablets: twice daily
• 📆 Extended-release: once daily (not approved for dogs under 10 lbs)
• 🍽️ Can be given with or without food
• 🌡️ Store in a container protected from light
• 🚫 Do not cut or split extended-release tablets

⚠️ Who Should Not Use Proin

• 💔 Dogs with heart disease
• 🧬 Dogs with high blood pressure
• 🐶 Dogs with glaucoma, hyperthyroidism, or diabetes
• ⚠️ Dogs under 10 lbs (extended-release tablets)

💢 Side Effects

Common (mild):

• 🏃 Restlessness or hyperactivity
• 💧 Increased thirst
• 🫀 Rapid heart rate
• 🍽️ Appetite changes
• 😟 Panting or mild stomach upset

Rare but serious:

• ⚠️ High blood pressure (hypertension)
• 🧪 Protein in urine
• 📉 Depleted norepinephrine stores (tolerance over time)

🧪 Drug Interactions

• ❌ Avoid with L-Deprenyl (Anipryl)—can dangerously alter blood pressure
• ⚠️ Use cautiously with tricyclic antidepressants (e.g., amitriptyline)
• ⚠️ Risk of hypertension with NSAIDs or amitraz tick products
• ✅ Can be used with estrogens like DES or estriol for synergistic effect

⏳ Onset of Action

Proin does not work immediately. It may take several days of dosing to assess whether it’s effective for urinary control.

📋 Before Starting Proin

• 🧪 Rule out kidney disease or bladder infection first
• 🩺 Evaluate blood pressure and cardiovascular status
• 📈 Expect regular monitoring in long-term use

📲 Ask a Vet If...

• 📞 You notice unusual behaviors or symptoms after starting Proin
• 💧 Urine leakage persists after 1–2 weeks of therapy
• 🧬 Your dog has pre-existing conditions or is on other medications

Use the Ask A Vet app for real-time guidance if you have questions about incontinence causes or safer medication alternatives 🐾💬

✅ Summary

• ✔️ Proin (phenylpropanolamine) is effective for controlling urinary incontinence in dogs
• ✔️ Best given consistently, with close monitoring if long-term
• ⚠️ Not for dogs with heart, kidney, or endocrine disease
• ⚠️ Watch for behavior changes, hypertension, or increased thirst
• ✔️ Safe for most dogs when used as directed by your vet

Urine leakage is frustrating—but treatable. With proper vet care, most dogs on Proin lead clean, confident lives 💛

— Dr Duncan Houston BVSc