Vet Guide to Domperidone: Equidone® Gel for Fescue Toxicosis in Mares 🐴

Vet Guide to Domperidone (Equidone® Gel) in 2025 🐴

Hello, I’m Dr Duncan Houston, BVSc—founder of Ask A Vet. In this detailed 2025 guide, I discuss **domperidone**, the active ingredient in Equidone® Gel, used strategically in pregnant mares to prevent **fescue toxicosis**. Learn how it works, when to dose, common side‑effects, foal-care implications, and veterinary monitoring to ensure safe and effective use. 🐴💊

📘 What Is Domperidone?

Domperidone is a peripherally acting dopamine D₂‐receptor antagonist that increases prolactin, promoting milk production and counteracting toxic alkaloids from endophyte-infected tall fescue :contentReference[oaicite:3]{index=3}. In mares, it helps prevent late-term agalactia, dystocia, and prolonged gestation associated with fescue toxicosis.

✅ Approved Use: Preventing Fescue Toxicosis

• Equidone® Gel is FDA-approved for pregnant mares fed endophyte-infected fescue from **10–15 days before expected foaling** until up to **5 days post-foaling** :contentReference[oaicite:4]{index=4}.
• Typical dosage: **1.1 mg/kg once daily** (≈0.5 mg/lb) via oral gel syringe, typically ~5 cc for a 500 kg mare :contentReference[oaicite:5]{index=5}.
• Dosing must consider previous use—dial the syringe cumulatively during the treatment course :contentReference[oaicite:6]{index=6}.

📐 Dosing Instructions

• Start dosing **10–15 days before expected foaling date**; continue through foaling and up to **5 days after** if lactation is insufficient :contentReference[oaicite:7]{index=7}.
• Syringe dosing is cumulative: e.g., 5 cc first day, then 10 cc, 15 cc, etc., up to 25 cc by day 5 :contentReference[oaicite:8]{index=8}.
• Do **not** use in horses intended for human consumption :contentReference[oaicite:9]{index=9}.
• Not recommended for stallions, non-pregnant mares, or within **15 days of foaling** with short-term interruption :contentReference[oaicite:10]{index=10}.

⚠️ Side‑Effects & Foal Health Risks

Mare concerns:

• **Premature lactation** (milk dripping before foaling) is common; may occur in up to 1–10% of treated mares :contentReference[oaicite:11]{index=11}.
• Risk of **premature birth**, **low foal birth weight**, and **foal morbidity** if administered earlier than 15 days before foaling :contentReference[oaicite:12]{index=12}.

Foal concerns:

• **Failure of passive transfer (FPT):** notably high—up to 81%, even in mares without milk dripping :contentReference[oaicite:13]{index=13}.
• Foals may show **loose stool**, low immunoglobulin levels; need IgG testing and potentially plasma transfusion :contentReference[oaicite:14]{index=14}.

🚫 Contraindications

• Do **not use** in mares more than 15 days before expected foaling—risk of early labor and underweight foals :contentReference[oaicite:15]{index=15}.
• Avoid in horses with **GI obstruction** as domperidone is prokinetic :contentReference[oaicite:16]{index=16}.
• Not evaluated in stallions, non-pregnant mares or varying equine classes :contentReference[oaicite:17]{index=17}.

🩺 Monitoring & Veterinary Oversight

• All **foals** should have **IgG levels tested** shortly after birth due to FPT risk :contentReference[oaicite:18]{index=18}.
• Veterinarian should confirm **expected foaling date** and ensure proper dosing schedule :contentReference[oaicite:19]{index=19}.
• Advise mare owners to **watch for early milk**, foal weakness, or low birthweights.
• Monitor for **premature births**—if foaling occurs before 320 days, neonatal support and IgG absorption plans should be in place :contentReference[oaicite:20]{index=20}.

🔗 Drug Interactions & Handling

• Domperidone is metabolized via CYP3A4—co-administration with **erythromycin, ketoconazole**, or other CYP3A4 inhibitors may increase blood levels :contentReference[oaicite:21]{index=21}.
• Domperidone is **P-glycoprotein substrate**—caution in dogs with MDR1 gene mutations when extrapolated to compounded use :contentReference[oaicite:22]{index=22}.
• Human exposure precautions: pregnant women and nursing mothers should avoid handling the gel due to hormonal effects :contentReference[oaicite:23]{index=23}.

🏡 Clinical Example

A 520 kg mare expected to foal on June 25—Vet started Equidone® Gel on June 10 (scheduled 5 cc daily by dial ring). Foaled uneventfully on June 24. Foal tested IgG and received plasma transfusion for mild FPT. Mare did not drip milk prematurely.

❓ FAQs

Can I use Equidone® after foaling?

Yes—continue up to 5 days postpartum if mare fails to lactate adequately :contentReference[oaicite:24]{index=24}.

Is Equidone® safe in all pregnant mares?

Yes if used starting ≤15 days before foaling—but avoid earlier to reduce foal complications :contentReference[oaicite:25]{index=25}.

Could this cause false milk‑calcium test results?

Yes—domperidone may yield false-positives on calcium-based foaling prediction tests :contentReference[oaicite:26]{index=26}.

📌 Final Takeaways

• Domperidone (Equidone® Gel) is a **FDA-approved, once-daily oral gel** that prevents fescue toxicosis when used in last 10–15 days of gestation.
• Ideal dose is **1.1 mg/kg daily**, but must stop within 15 days of expected foaling to avoid premature birth and low-birthweight foals.
• Common side–effects include **premature lactation** and **failure of passive transfer (FPT)**—all foals should have IgG tested, and support given when needed.
• Not suitable before last 15 days, in GI obstruction, or for isolation; monitor mares and foals closely with veterinary guidance.
• Domperidone metabolism can be affected by other drugs like ketoconazole or erythromycin; use gloves when handling gel to prevent human exposure.

Considering Equidone® Gel for your pregnant mare? Download the Ask A Vet app for dosing reminders, foaling date tracking, side‑effect alerts, and direct veterinary support—ensuring safe, effective fescue toxicosis prevention in 2025 and beyond. 🐾❤️