🧴 Vet’s 2025 Guide to Transdermal Medications in Dogs and Cats: How Skin-Delivered Treatments Work 🐾

By Dr Duncan Houston, BVSc

Giving medications to pets—especially cats—can be tricky. Pills get spit out, injections can be stressful, and appetite-dependent treatments sometimes fail. That’s where transdermal medications come in. 🧴💊

This 2025 guide explains how transdermal meds work, when they’re appropriate, and how to use them safely for your dog or cat. Whether you’re managing pain, thyroid disease, or appetite loss, this form of treatment could make life easier for both of you. 🐶🐱

🔬 What Are Transdermal Medications?

Transdermal means "through the skin." These medications are applied to the skin and absorbed into the bloodstream—similar to how oral pills or injections deliver medication. ✅

They come in various forms:

• 💧 Gels or creams (most common)
• 🌫️ Solutions (liquid)
• 📎 Adhesive patches

Important: Unlike topical ointments that treat skin issues locally, transdermal meds are systemic—they work throughout the body. 🌍

📦 Common Transdermal Medications

• 🩺 Methimazole: For hyperthyroidism in cats
• 🍽️ Mirtazapine: For stimulating appetite
• 💥 Fentanyl patches: For post-surgical or chronic pain (dogs & cats)

Most gels are custom-compounded at veterinary pharmacies. These are applied to the inner ear (cats) or abdomen (dogs), where the skin is thin for easier absorption. 🐾

📋 How Do Transdermal Medications Work?

The skin is naturally a barrier—but transdermal drugs are specially formulated to penetrate it and enter the bloodstream through capillaries. 🧬

Adhesive patches (like pain control systems) contain medication that’s slowly released through the skin over time. ⏳

✅ Pros of Transdermal Medications

• 😸 Stress-free for pets who hate pills
• 🚫 Bypasses liver metabolism (important for pets with liver conditions)
• 🤢 Less likely to cause stomach upset
• 🧪 Excellent for long-term daily dosing

⚠️ Cons and Limitations

• 🧪 Not all drugs are absorbable through skin
• 💉 Dosing may be less precise than pills or injections
• 🐾 Only small doses can be given this way
• 🩹 Skin irritation or contact dermatitis is possible
• 👶 Risk of human or pet exposure if not applied correctly

Important: Not every medication is safe or effective in transdermal form. Ask your vet whether there’s research to support the compound’s use. 📚

📍 Where to Apply Transdermal Meds

• 🐱 Inside of the ear (pinna)
• 🐶 Dogs: Belly or inside thigh (thin-skinned areas)

Never apply to:

• 🐾 Fur-covered areas
• 🧼 Dirty, inflamed, or infected skin
• 🧒 Places that children or other pets might lick

🧴 How to Apply Transdermal Medications Safely

1. 🧤 Wear gloves: Always! These drugs can be absorbed through your skin too.
2. 🧼 Clean the site: Use lukewarm water to remove residue before each application.
3. 🕊️ Calm your pet: Don’t apply when they’re agitated or anxious.
4. 🧊 Use shaved areas carefully: Avoid irritation and rotate application sites if needed.
5. 📅 Follow vet instructions precisely: Apply the correct dose at the correct time.
6. 🗑️ Dispose of safely: Used patches should be kept away from kids or other pets.

💬 Talk to Your Vet If…

• 🐕 Your pet is scratching or licking the application site
• 📉 The drug doesn’t seem to be working
• 🧪 Your pet’s condition worsens or side effects appear

📛 Warning Signs to Watch For

• 📛 Redness, scabbing, or hair loss at the site
• 🤢 Vomiting or behavioral changes (overdose risk)
• 💤 Excessive sedation, especially with pain patches

Call your veterinarian immediately if any of these occur. ⏱️

📱 Ask A Vet Can Help

Need help applying a gel? Wondering if your pet qualifies for a transdermal option? Visit AskAVet.com for:

• 💬 Medication tutorials & walkthroughs
• 📷 Submit photos of irritation or application sites
• 📲 Personalized advice based on your pet’s diagnosis

📲 Download the Ask A Vet App

Track transdermal schedules, get application alerts, and speak directly to a vet if questions arise—all from your phone. 🐶📱🐱

🎯 Final Thoughts

Transdermal medications offer convenience, reduced stress, and life-changing treatment options—especially for long-term management. 🧴💊

But they’re not right for every drug or every pet. Always consult your veterinarian, use products backed by science, and monitor for skin reactions or dosing concerns. ✅

When needles and pills become a struggle, skin-deep solutions might be the answer. 💡🐾