Moxidectin for Pets in 2025 🐾

Moxidectin is a powerful and long-acting anti-parasite medication that protects pets from internal and external parasites, including heartworms, mange, and intestinal worms. I’m Dr Duncan Houston BVSc, and in this 2025 veterinary guide, I’ll walk you through how Moxidectin works, the safest way to use it, and what pet parents need to watch for 🐶🐱

💊 What Is Moxidectin?

Moxidectin is a macrocyclic lactone—a class of antiparasitic drugs that interfere with the nervous system of parasites like worms and mites, while leaving mammals unaffected. It’s found in several branded products including:

• Advantage Multi®
• ProHeart® 6 & ProHeart® 12 (injectables)
• Simparica Trio®
• Other monthly topicals or chews

📦 How Moxidectin Is Administered

💧 Topical (monthly):

• Applied once monthly to skin between the shoulders
• Protects against heartworm, hookworm, roundworm, whipworm, and mites (depending on the product)
• Use gloves and wash hands afterward

💉 Injectable (ProHeart):

• Given by a vet every 6 or 12 months
• Approved for heartworm prevention and hookworm control
• Dogs must be at least 6 months old
• Do not give with vaccines—risk of anaphylaxis

🦠 What Parasites Does It Treat?

Depending on the product formulation, Moxidectin can treat and prevent:

• ❤️ Heartworms (prevention only)
• 🪱 Hookworms, roundworms, whipworms
• 🐛 Sarcoptic mange (dogs), notoedric mange & ear mites (cats)

⚠️ Side Effects

With Topical Form:

• 😴 Lethargy
• 🤮 Vomiting or diarrhea
• 🔥 Itching or hair loss at the application site
• 🐱 In cats: spinning, hiding, excessive grooming, or drunken gait

In Case of Oral Ingestion:

• 🚨 Vomiting, tremors, disorientation, panting
• 💥 Call your vet or Animal Poison Control immediately (888-426-4435)

🧬 MDR1 Mutation Considerations

Dogs with the MDR1 (ABCB1) gene mutation may be sensitive to certain drug interactions involving moxidectin.

At-Risk Breeds Include:

• Collies
• Shetland Sheepdogs
• Australian Shepherds
• Old English Sheepdogs

🧪 Test kits can be obtained from Washington State University. While standard moxidectin doses are safe for MDR1 dogs, caution is needed with drug combinations.

Risky Drug Interactions (in MDR1 dogs):

• Cyclosporine
• Spinosad
• Diltiazem
• Erythromycin
• Itraconazole / Ketoconazole
• Spironolactone

📅 If You Miss a Dose

• 💧 For topicals: Apply as soon as remembered. Do not double the next dose.
• 💉 For injectables: Resume as soon as possible. Protection fades after expiration.

⚠️ Important Cautions

• ❌ Do not use topical moxidectin on irritated or broken skin
• 👶 Keep children and other pets away from treated area for 2 hours (dogs) or 30 minutes (cats)
• 🧊 Store at room temperature, away from heat and light
• ❌ Injectable version should not be used in sick or debilitated dogs
• ⚠️ Tapeworms are not affected by moxidectin—use praziquantel if needed

📲 Ask a Vet for Help

Confused by parasite options? Want to ensure moxidectin is right for your pet’s breed or health needs? Use the Ask A Vet app for expert veterinary guidance in real time 🐾💬

✅ Summary

• ✔️ Moxidectin prevents heartworms and treats many GI and skin parasites
• ✔️ Safe monthly topical or long-lasting injectable
• ⚠️ Side effects rare, but monitor for vomiting or skin irritation
• ✔️ MDR1 dogs can safely receive moxidectin, but watch for drug interactions
• ✔️ Do not use with vaccines or in puppies under 6 months (injectable form)

Still have questions? Download the Ask A Vet app for expert guidance on parasite prevention, safety, and breed-specific risks 🩺🐶🐱

— Dr Duncan Houston BVSc