Oxibendazole
Also known as: Anthelcide EQ · Dio · Equidin · Equitac · Loditac · SKF-30310
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Audited v13 dosing evidence
Structured calculator evidenceEncephalitozoon cuniculi infection after diagnostic risk-benefit discussion
- q24h · 30d
Governing clinical context (9)
- Infections marked by ocular, CNS, and renal disease
- Otitis interna and/or media
- Most common cause of vestibular signs must exclude first
- CNS infections (toxoplasmosis, abscess), neoplasia, trauma
- Many North American and European rabbits will be positive, indicative of prior (in utero) exposure and not necessarily active disease
- Definitive diagnosis based on organism (obligate intracellular microsporidian parasite) identification in affected tissues, generally postmortem
- Head CT/MRI is considered for excluding bulla disease, abscess, neoplasia
- Positive serology and response to treatment supports presumed diagnosis, but risk/benefit discussion required prior to initiation
- Risk of bone marrow suppression/aplastic anemia/pancytopenia with therapy must be considered/discussed prior to therapy
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Oxibendazole is a benzimidazole anthelmintic primarily utilized in equine medicine for the eradication of various internal nematodes.
- Key Targets: Large roundworms (Parascaris equorum), large strongyles (Strongylus edentatus, S. equinus, S. vulgaris), small strongyles, threadworms, and pinworms (Oxyuris equi).
- Clinical Pearl: Benzimidazole resistance is a widespread and growing concern in equine parasitology, particularly among small strongyles (cyathostomins) and Parascaris equorum. Routine Fecal Egg Count Reduction Testing (FECRT) is highly recommended to monitor farm-specific efficacy. A reduction value of less than 90% in 5-10 horses suggests resistance on a given farm.
- While primarily labeled for horses, it has historical and off-label applications in cattle, sheep, and swine.
Mechanism of action
Benzimidazoles exert their anthelmintic effect by selectively binding to nematode β-tubulin.
- Primary Mechanism: Binds to tubulin → prevents tubulin polymerization → inhibits microtubule formation. This disrupts essential intracellular transport systems within the parasite.
- Secondary Mechanism: At higher concentrations, it disrupts metabolic pathways by inhibiting key enzymes such as fumarate reductase and malate dehydrogenase, ultimately starving the parasite of energy (ATP depletion).
- Pharmacological Note: The selective toxicity arises because benzimidazoles have a much higher affinity for nematode tubulin compared to mammalian tubulin.
Safety & warnings
Contraindications
- Severely debilitated horses
- Horses suffering from colic
- Toxemia
- Infectious disease
Adverse effects
- Hypersensitivity reactions (secondary to antigen release by dying parasites)
- Periportal hepatitis (historically noted in dogs when combined with diethylcarbamazine)
Precautions
Use with caution in debilitated animals. Resistance to benzimidazoles is highly prevalent; fecal egg count reduction testing (FECRT) is strongly recommended to ensure efficacy.
Monitoring
- Efficacy (via Fecal Egg Count Reduction Test - FECRT)
Overdose
Doses of 60 times those recommended elicited no adverse reactions in horses tested. It is unlikely that this compound would cause serious toxicity when given alone to horses.
Available products
Formulations
- Oral suspension
- Oral paste
Veterinary
- Oxibendazole Suspension: 100 mg/mL (10%)
- Oxibendazole Oral Paste: 227 mg/gram (22.7%)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Unless otherwise directed by the manufacturer, oxibendazole products should be stored at room temperature; protect from freezing.
Client information
Important: This medication is prescribed to treat specific internal parasites in your animal.
- Administration: Shake the liquid suspension thoroughly before each use to ensure accurate dosing.
- Storage: Keep the medication at room temperature and do not allow it to freeze.
- Food Animal Warning: This medication must not be used in horses intended for human consumption.
- Side Effects: Side effects are very rare. Occasionally, a mild allergic reaction may occur as the parasites die off. Contact your veterinarian if your horse seems unwell after administration.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.