Diclazuril

BRAND NAMES

Diclazuril is marketed under several brand names, including Vecoxan and Coxiril, as well as DiclaCare and Clinacox, which are commonly used for anticoccidial treatment in animals.

• Vecoxan: A veterinary formulation of diclazuril used to treat and prevent coccidiosis.

• Coxiril: Another diclazuril-based product employed as an anticoccidial agent.

• DiclaCare: An oral suspension containing diclazuril, produced by AdvaCare Pharma.

• Clinacox: A synonym and brand name for diclazuril, also used in the management of coccidial infections.

MECHANISM OF ACTION

Diclazuril is a synthetic anticoccidial agent that works by interfering with the normal differentiation and development of the intracellular stages (both asexual and sexual) of coccidial parasites. Its mode of action involves several cellular targets, including effects on a unique parasitic organelle, suppression of essential proteins, and disruption of actin dynamics.

Key Mechanisms of Action:

• Targeting the Apicoplast (a chloroplast-derived organelle): Diclazuril binds to a specific protein complex within the parasite’s plastid, which is homologous to the D1 protein found in photosynthetic reaction centers. Because mammalian cells lack this organelle, the drug exhibits high selectivity and low toxicity to the host.

• Disruption of Parasite Development: Diclazuril is effective against both asexual and sexual stages of the parasite’s life cycle. It induces severe degenerative changes in the first- and second-generation schizonts and gamonts, leading to vacuolation, loss of internal structure, and incomplete merogony or gamogony. This interruption of parasite development prevents completion of the life cycle and inhibits oocyst shedding.

PHARMACOKINETICS:

Absorption

Diclazuril is absorbed in a delayed and variable manner following standard oral administration due to its low water solubility. However, its absorption and bioavailability can be significantly improved by administering it in specialized formulations, such as a sodium salt solution or a nanoemulsion.

Distribution

Diclazuril is an antiprotozoal compound whose distribution depends on the species and route of administration. It tends to accumulate mainly in the liver, kidneys, fat, and muscle tissues. Although its oral bioavailability is relatively low in certain animals, it can achieve effective therapeutic levels in the central nervous system of horses.

Metabolism

Diclazuril undergoes minimal metabolism in most animal species, which contributes to its prolonged efficacy and low toxicity. Following administration, it is slowly absorbed and largely retained in its unchanged form, with only limited hepatic metabolism producing small amounts of inactive metabolites. 

Excreation

Diclazuril is primarily eliminated through fecal excretion as the unchanged drug, with minimal amounts excreted in urine. Elimination rates and residual times vary by species and tissue type, with the liver generally showing the fastest elimination but the kidney potentially holding residues longer.

PHARMACODYNAMICS

Diclazuril is an anticoccidial drug that targets protozoan parasites, especially Eimeria species. It works by interfering with their asexual reproductive cycle, preventing the parasites from multiplying. By disrupting the development of the parasites, diclazuril reduces intestinal damage and associated symptoms in infected animals. It is primarily used in poultry and livestock to control coccidiosis. Its selective action against the parasites ensures minimal effects on the host animal.

ADMINISTRATION
Diclazuril is usually administered orally, either through feed or drinking water, depending on the species and purpose. It is commonly mixed in poultry or livestock feed to provide continuous prophylactic exposure against coccidial infections. The medication is also available as a suspension for oral dosing in individual animals. Proper administration ensures uniform distribution and effective control of coccidiosis.

DOSAGE AND STRENGTH

The typical dose varies by animal species and purpose (prevention or treatment). In poultry, the recommended dose is generally around 0.5–1 mg/kg of feed. For livestock, doses are adjusted based on body weight and severity of infection. Exact dosing should follow veterinary guidance to ensure efficacy and avoid underdosing or toxicity.

DRUG INTERACTIONS

There are limited known drug interactions with diclazuril. However, concurrent use with other anticoccidial agents should be done cautiously to avoid antagonistic effects or overdosing. Always consult a veterinarian before combining with other medications, particularly ionophores or polyether antibiotics in feed.

FOOD INTERACTIONS

Diclazuril can be safely administered with feed or water and does not have major food interactions. Adequate mixing in feed ensures uniform intake. No known interactions with common dietary components affect its efficacy.

CONTRAINDICATIONS
Diclazuril is contraindicated in animals with known hypersensitivity to the drug or its formulation. It should not be used in young animals outside the recommended age or in species for which it is not approved. Avoid use in severely ill or debilitated animals without veterinary supervision.

SIDE EFFECTS

• Slight decrease in appetite or feed consumption

• Temporary stomach or intestinal disturbances

• Occasional diarrhea in sensitive animals

• Fatigue or lowered activity levels

• Rare cases of allergic or hypersensitivity reactions

OVERDOSE
Excessive administration of diclazuril can lead to toxicity, though it is relatively safe compared with other anticoccidials. Signs of overdose may include lethargy, loss of appetite, or gastrointestinal upset. Veterinary intervention is recommended if overdose is suspected.

TOXICITY
Diclazuril has a wide safety margin, but very high doses may cause mild liver or kidney stress in some animals. Chronic overdosing should be avoided, and withdrawal periods must be observed before meat or egg consumption to prevent residue accumulation.