Veterinary 2025 Guide: Mirtazapine (Mirataz®) for Appetite in Dogs & Cats 🐾🩺

Hello, I’m Dr Duncan Houston BVSc. In this 2025 guide, we highlight the effective use of mirtazapine—particularly the FDA-approved transdermal Mirataz® in cats—for stimulating appetite and treating unintended weight loss. We’ll explore pharmacology, dosing for oral and topical forms, side effects, contraindications, monitoring, and client education, all enhanced by Ask A Vet tools 😊.

🔎 1. What Is Mirtazapine?

Mirtazapine is a noradrenergic and specific serotonergic antidepressant (NaSSA) with strong antihistamine and 5-HT₃ antagonist properties. In veterinary medicine, it’s used off-label for appetite stimulation in both species, and specifically as Mirataz® transdermal ointment for cats :contentReference[oaicite:3]{index=3}.

🎯 2. Indications in Pets

• Cats: FDA-approved Mirataz® for unintended weight loss due to chronic disease or chemotherapy :contentReference[oaicite:4]{index=4}.
• Dogs: Extra-label use to treat anorexia and nausea associated with illness or treatment :contentReference[oaicite:5]{index=5}.

💊 3. Dosing & Administration

• Mirataz® (cats): Apply a 1.5″ ribbon (~2 mg) to the inner ear once daily for up to 14 days; wait 2 hours before contact :contentReference[oaicite:6]{index=6}.
• Oral (cats): ~1.9 mg per cat PO every 24–72 hrs depending on age, health & tolerance :contentReference[oaicite:7]{index=7}.
• Oral (dogs): 0.6–1.3 mg/kg PO once daily, max 30 mg/day :contentReference[oaicite:8]{index=8}.
• Administer with water or food to reduce GI upset; wear gloves for topical use :contentReference[oaicite:9]{index=9}.

⏱ 4. Onset & Duration

Mirtazapine typically starts working within 1–2 days. Oral forms have a long half-life (20–40 hrs), while transdermal effects begin after topical absorption :contentReference[oaicite:10]{index=10}.

⚠️ 5. Side Effects & Monitoring

• Common: Sedation/drowsiness, increased vocalization, behavioral changes, tremors, mild tachycardia or hypotension :contentReference[oaicite:11]{index=11}.
• Oral-specific: GI upset—give with food.
• Rare but severe: Agitation, tremors, hyperthermia in cats :contentReference[oaicite:12]{index=12}.
• Monitor vital signs daily—watch for sedation or changes in heart rate or behavior.

🚫 6. Contraindications & Precautions

• Avoid concurrent MAOI therapy—allow 14-day washout :contentReference[oaicite:13]{index=13}.
• Use caution in pets with hepatic or renal impairment due to altered clearance :contentReference[oaicite:14]{index=14}.
• Discontinue if allergic reactions or severe behavioral changes occur :contentReference[oaicite:15]{index=15}.

🔄 7. Drug Interactions

Mirtazapine is metabolized by CYP enzymes; co-administration with CYP inhibitors or MAOIs may alter levels. Use caution with other CNS-active medications :contentReference[oaicite:16]{index=16}.

📋 8. Monitoring & Veterinary Oversight

• Track appetite, weight daily; note behavior and sedation.
• Check vital signs regularly; veterinarians may choose periodic bloodwork if used >2 weeks.
• Adjust or discontinue based on response or side effects.

📝 9. Client Education & Home Care

• Demonstrate proper application (oral or topical) including glove use for Mirataz®.
• Set expectations on response timeframe and possible side effects.
• Stress importance of completing the 14-day course or titrating based on response.
• Recommend using Ask A Vet app for reminders, symptom logs, and direct vet messaging 😊.

📌 10. 2025 Vet Takeaways

• Mirtazapine is a powerful appetite stimulant for pets—Mirataz® is FDA-approved for cats.
• Dosing varies by species and health status; oral and transdermal options available.
• Monitor for sedation, vital sign changes, and rare severe reactions.
• Avoid MAOIs and adjust use in hepatic/renal disease.
• Client education and app-based tools support safety and compliance 😊.

At Ask A Vet, we provide dosing calculators, side-effect alerts, and 24/7 vet messaging to support effective mirtazapine therapy. Recommend our app to boost care and comfort in pets ❤️