# Diclazuril: veterinary dose and monograph

> Diclazuril is a veterinary antiparasitic. Triazine (benzeneacetonitrile) anticoccidial active against Eimeria. Indications include coccidiosis (Eimeria) in calves, lambs and kids — treatment/prevention; poultry coccidiosis (in-feed coccidiostat); equine protozoal myeloencephalitis (EPM) — Sarcocystis neurona (Protazil). This monograph lists 6 reference doses for dogs, cats, cattle, horses, sheep and poultry, each with route, frequency and source, plus meat and milk withdrawal periods for food animals.

Source: https://vetmasterji.com/drugs/diclazuril · Last reviewed: 2026-10-01

## At a glance

- **Drug class:** Antiparasitic
- **Also known as:** Vecoxan, Clinacox, Protazil
- **Species with doses:** Dogs, Cats, Cattle, Horses, Sheep and Poultry
- **General dose range:** 1 mg/kg PO single dose (ruminants) / continuous (poultry) — check the species tables for the indication
- **Routes:** PO
- **Last reviewed:** 1 October 2026

## Indications

- Coccidiosis (Eimeria) in calves, lambs and kids — treatment/prevention
- Poultry coccidiosis (in-feed coccidiostat)
- Equine protozoal myeloencephalitis (EPM) — Sarcocystis neurona (Protazil)

## Diclazuril dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

### Dogs

*Diclazuril doses for dogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Coccidiosis | 25 mg/kg | PO | once | — |

- Coccidiosis: Plumb’s p.389 (Greene 2006): dogs and cats 25 mg/kg PO once.

### Cats

*Diclazuril doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Coccidiosis (Isospora) | 25 mg/kg | PO | once | — |

- Coccidiosis (Isospora): Plumb’s p.389: 25 mg/kg PO once (Greene 2006; Dubey 2009); kittens 1 mL (2.5 mg) of the sheep suspension per 4 kg (Miller 2007).

### Cattle

*Diclazuril doses for cattle*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| Coccidiosis (calves) | 1 mg/kg | PO | single dose (repeat in outbreaks) | — | no slaughter withdrawal |

- Coccidiosis (calves): Plumb’s p.389 (Vecoxan UK label): 1 mg/kg (1 mL of 2.5 mg/mL per 2.5 kg) PO once, 14 days after moving into a high-risk environment; treat all calves in the pen.

### Horses

*Diclazuril doses for horses*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| EPM (Sarcocystis neurona) | 1 mg/kg | PO | q24h | 28 days |

- EPM (Sarcocystis neurona): Papich 5e and Plumb’s p.389 (Protazil label): 1 mg/kg top-dressed on feed daily for 28 days (at steady state 0.5 mg/kg gives similar levels). Prevention (Papich): 0.5 mg/kg every 3–4 days.

### Goats

*Diclazuril doses for goats*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| No reference dose for this species | Not established in Papich 5e or Plumb’s 10e — do not extrapolate from another species | — | — | — | — |

- No reference dose for this species: Neither Papich 5e nor Plumb’s gives a diclazuril dose for goats (Plumb’s lists lambs and calves only); the previous row copied the lamb dose.

### Sheep

*Diclazuril doses for sheep*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| Coccidiosis (lambs) | 1 mg/kg | PO | single dose | — | no slaughter withdrawal |

- Coccidiosis (lambs): Plumb’s p.389 (Vecoxan UK label): 1 mg/kg PO once — preventively at 4–6 weeks of age, with a second dose about 3 weeks later under high infection pressure; treat all lambs.

### Poultry

*Diclazuril doses for poultry*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| Coccidiosis (in feed) | ~1 ppm in feed, continuously | PO | continuous in feed | — | 5d slaughter |

- Coccidiosis (in feed): Dosed by feed concentration (~1 ppm) per label.

### Buffalo

No buffalo-specific doses are on file, so buffalo are dosed as cattle.

*Diclazuril doses for buffalo*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| Coccidiosis (calves) | 1 mg/kg | PO | single dose (repeat in outbreaks) | — | no slaughter withdrawal |

- Coccidiosis (calves): Plumb’s p.389 (Vecoxan UK label): 1 mg/kg (1 mL of 2.5 mg/mL per 2.5 kg) PO once, 14 days after moving into a high-risk environment; treat all calves in the pen.

## Contraindications

Known hypersensitivity. Verify food-animal withdrawal per product. Otherwise few — wide safety margin. Ensure correct diagnosis (coccidiosis vs other enteritis; EPM confirmation in horses).

## Species-specific warnings

> **Caution:** Horses: Used for EPM (Sarcocystis neurona) — neurologic signs may transiently worsen early in treatment; confirm diagnosis and consider anti-inflammatory support.

## Adverse effects

- Generally very well tolerated
- Rare GI upset
- EPM treatment: transient worsening of neurologic signs early (parasite die-off) is possible

## Drug interactions

- No clinically important systemic drug interactions reported
- In EPM, sometimes used in protocols with anti-inflammatories to manage die-off inflammation

## Pregnancy and lactation

Considered safe at label doses in breeding/pregnant animals; widely used in young stock.

## Monitoring

- Faecal oocyst counts / clinical response (coccidiosis)
- Neurologic improvement over the course (EPM)
- Withdrawal-period compliance (poultry)

## Toxicity and overdose

Very wide safety margin — overdose is generally well tolerated with at most mild GI signs. No significant target-organ toxicity at therapeutic or modest supratherapeutic doses.

Management: Supportive only; no specific antidote required given the wide margin. Symptomatic care for any GI upset.

## Clinical pearls

- A convenient SINGLE-DOSE oral coccidiocide for calves, lambs and kids — good for outbreak control
- Very wide safety margin — one of the better-tolerated anticoccidials
- In horses it is an EPM treatment (Protazil) — confirm the diagnosis and watch for early die-off worsening
- For prevention, time dosing to the expected pre-patent period of the Eimeria challenge

## Mechanism of action

A triazine antiprotozoal that acts on the apicomplexan parasite (Eimeria/Sarcocystis), disrupting development of the asexual and sexual intracellular stages — interfering with the apicoplast/organellar function and halting schizogony and gametogony. This both treats active infection and prevents oocyst shedding. The same class action underlies its efficacy against Sarcocystis neurona in EPM.

## Formulations and products

- Oral suspension 2.5 mg/mL (Vecoxan)
- Feed premix (Clinacox, poultry)
- Oral pellets / paste (equine EPM, Protazil)
- Vecoxan (Elanco) — Diclazuril 2.5 mg/mL oral suspension, Oral suspension
- Protazil (Merck Animal Health) — 1.56 % diclazuril pellets, Oral pellets

## Storage

Suspension/pellets/premix: 15–30 °C, dry, protect from light; shake suspension before use.

## Before you use this dose

> **Caution:** Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

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## Frequently asked questions

### What is the dose of Diclazuril for dogs?

Reference doses for Diclazuril in dogs: 25 mg/kg PO once (Coccidiosis). Confirm against the label and the patient before use.

### What is the dose of Diclazuril for cats?

Reference doses for Diclazuril in cats: 25 mg/kg PO once (Coccidiosis (Isospora)). Confirm against the label and the patient before use.

### What is the dose of Diclazuril for cattle?

Reference doses for Diclazuril in cattle: 1 mg/kg PO single dose (repeat in outbreaks) (Coccidiosis (calves)). Confirm against the label and the patient before use.

### What is the withdrawal period for Diclazuril?

Cattle, PO (Coccidiosis (calves)): no slaughter withdrawal; Sheep, PO (Coccidiosis (lambs)): no slaughter withdrawal; Poultry, PO (Coccidiosis (in feed)): 5d slaughter. Follow the product label and national regulations where they differ.

### When should Diclazuril not be used?

Known hypersensitivity. Verify food-animal withdrawal per product. Otherwise few — wide safety margin. Ensure correct diagnosis (coccidiosis vs other enteritis; EPM confirmation in horses).

### What are the side effects of Diclazuril in animals?

Generally very well tolerated; Rare GI upset; EPM treatment: transient worsening of neurologic signs early (parasite die-off) is possible.

## Sources

- Plumb's Veterinary Drug Handbook
- Merck Veterinary Manual, 11th edition
- Papich, Papich Handbook of Veterinary Drugs, 5th edition

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VetMasterJi is a clinical decision-support and education platform for veterinary professionals and students. It does not provide veterinary advice, diagnosis or treatment for specific animals. All drug doses, calculators and differentials are references that must be independently verified before clinical use; the attending registered veterinarian remains solely responsible for every clinical decision.