The medication, a combination of levamisole and oxyclozanide, is a veterinary anthelmintic used for managing symptoms related to parasitic infections in ruminants. The product is indicated for the treatment and control of both nematode and fluke infections.

The medication is applied across domains where additional symptomatic support is needed, covering the three major groups of internal parasites: roundworms (gastrointestinal and lungworms), tapeworms, and liver and rumen flukes. It is commonly used to help with infections caused by critical species like Haemonchus spp., Dictyocaulus spp., and adult Fasciola spp. This range of activity is relevant when supportive symptom management is appropriate in complex, mixed-species infections.

The medication is applied in addressing the adult liver flukes associated with conditions involving inflammatory or irritative processes, such as Chronic Fascioliasis. It also helps manage symptoms related to systemic imbalance, including impaired growth and weight loss, in situations where symptoms are linked to organ-specific functional stress. This action may support the animal during difficult episodes by easing distress and assists with maintaining functional stability.

“The medication is used to help with distressing symptoms that interfere with daily functioning and supports general well-being during symptomatic phases.”

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Quick Fact: Relief for Chronic Parasitic Burden
Nilzan contributes to managing a wide range of parasitic infections by targeting not only easily managed adult worms, but also immature larval stages and inhibited Dictyocaulus viviparus (lungworm larvae). This is relevant for managing conditions that involve episodic or fluctuating manifestations.

Regulatory References

1. UK Veterinary Medicines Directorate

Eligibility Scope

Category	Official Regulatory Statement
Populations for whom use is allowed	Cattle and Sheep are the officially established target species for treatment.
Populations for whom use is contraindicated	Dogs and Horses are explicitly prohibited. Use is also forbidden in animals with known hypersensitivity to the active ingredients.
Lactation Status	Sheep and Goats producing milk for human consumption are contraindicated due to residue risk. Use may be permitted in lactating dairy cattle.
Age-related rules	Calves and Lambs are eligible but treatment is conditional upon accurate bodyweight assessment.
Conditional Restrictions	Use requires caution in animals with severe liver damage or those under significant stress, including heavily pregnant animals.

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Eligibility Classifications

Category	Classification
Eligibility severity classification	Contraindicated (Absolute prohibition) applies to non-target species and animals with concurrent organophosphorus compound treatment history.
Eligibility-context constraints	Use is constrained by strict Milk Withholding Period (WHP) requirements and the animal's physical condition.

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Resulting Eligibility Structure

The medicine's eligibility profile is defined by species specificity and absolute prohibitions. The label explicitly forbids use in non-target animals, those with known hypersensitivity, or those recently treated with organophosphorus compounds. Conditional eligibility applies to groups such as those with severe liver damage or advanced pregnancy, mandating special caution as defined in regulatory documents. The profile distinguishes eligibility for lactating animals based on species and food safety constraints.

Interactions with other medicines and products

Official regulatory documents establish specific restrictions regarding the co-administration of Nilzan (Levamisole/Oxyclozanide) with other medicinal substances, primarily driven by the risk of additive or synergistic toxicity.

Contraindicated Combinations and Timing Rules

Co-administration with Organophosphorus compounds (e.g., phosphatic dips) is formally prohibited due to the documented risk of severe, enhanced adverse effects. The combination of Nilzan with Diethylcarbamazine citrate is also a substance that must be officially avoided.

To manage this interaction risk, regulatory labels establish a mandatory 14-day separation window. This rule states that the target animal must not be administered Organophosphorus compounds or Diethylcarbamazine citrate within 14 days preceding or following the administration of Nilzan.

Population-Dependent Interaction Notes

The official product information includes constraints related to the animal’s condition. The severity of interaction-related effects, such as signs of overdosage, is documented as being enhanced in animals that present with concurrent severe liver damage and/or dehydration at the time of treatment. No specific metabolic (e.g., CYP-mediated) or transporter-based interactions are explicitly detailed in the official regulatory documentation. Furthermore, no interactions with food, alcohol, or herbal products are documented for this veterinary product.

The dual mechanism of action is executed by two non-overlapping pharmacological components, targeting the physiological machinery of distinct parasite types.

Levamisole: Spastic Paralysis via Neuromuscular Agonism

Levamisole acts as an agonist on specific nicotinic acetylcholine receptors ( nAChR) located within the neuromuscular system of susceptible nematodes. This binding causes continuous cell membrane depolarization and sustained Na^+ influx, resulting in an irreversible spastic paralysis of the parasite's somatic musculature. This molecular cascade prevents the parasite from performing coordinated movements or maintaining its position against intestinal peristalsis.

Oxyclozanide: Metabolic Collapse via Mitochondrial Uncoupling

Oxyclozanide functions as an uncoupling agent within the cells of susceptible trematodes, disrupting the H^+ gradient across the inner mitochondrial membrane. This interference prevents the vital oxidative phosphorylation ( OXPHOS) pathway from generating Adenosine Triphosphate (ATP). The resulting profound energy depletion causes a widespread metabolic failure, eliminating cellular function in the parasite.

Nilzan, a combination anthelmintic containing Levamisole and Oxyclozanide, is administered exclusively by the oral route as a drench or suspension. The product is typically used as a single-dose treatment in most standard applications. Dosage must be based strictly on the animal’s live body weight, delivering the standardized rate of 7.5 mg of Levamisole Hydrochloride per kg and 15 mg of Oxyclozanide per kg of bodyweight.

Accurate determination of the animal's weight is a fundamental procedural requirement, which is essential to prevent underdosing. Proper administration requires mandatory preparation steps. The oral suspension container must be thoroughly shaken immediately prior to use to ensure a homogeneous mixture of the two active components. The medicine must be delivered using a calibrated and accurate dosing gun system, and under no circumstances should the product be mixed with any other solution beforehand.

While the primary regimen is a single application, specific schedules are sometimes applied, such as a conditional second identical dose 72 hours later for the control of certain fluke parasites. Further treatments may be applied at 10-14 day intervals in contexts where rapid re-infection is a risk. Specific exclusions may apply to young stock, such as lambs weighing less than 15 kg, depending on the indication.

Research Evidence / Overview of Studies for Nilzan

Evidence for Managing Gastrointestinal Parasitic Infections

Research on Nilzan was studied for its use in research contexts involving fluctuating or unstable symptoms related to gastrointestinal parasitic infections. These evaluations primarily utilized short-term controlled field trials. Research examined the effects of the combination on key outcomes, including Fecal Egg Count Reduction (FECR) and outcomes reflecting the rate of parasite egg change in naturally infected Ruminant populations, such as cattle, sheep, and goats.

Findings describe patterns observed in the studies where measurements of reduction in parasite egg counts were reported shortly following administration. However, evidence is limited regarding the long-term outcomes beyond the initial period. Data show patterns related to variability in reported efficacy that may be associated with the emergence of anthelmintic resistance in certain geographic areas. Furthermore, variability in consistency of findings was reported, which may stem from differences in how the active ingredients are processed across various ruminant species.

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Research on Trematode (Fluke) Infections

The research exploring the use of Nilzan against trematode or fluke infections primarily consisted of controlled efficacy trials. These studies generally explored whether the medicine's components were associated with changes related to adult liver flukes. The main outcome measured was the rate of change in fluke egg counts in the feces of infected animals.

Trials reported patterns related to fluke egg shedding in the observed populations. Research highlights patterns observed in the studies related to the adult stage of the parasite, but limited data are available comparing the long-term effectiveness against single agents. The evidence also primarily focuses on the adult parasite stages, meaning there is less information available on activity against all stages of the parasite lifecycle.

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The Overall Evidence Landscape and Key Limitations

The overall evidence landscape indicates that data show patterns related to consistency in some short-term findings; however, certainty remains low regarding various aspects of the medicine’s long-term performance. Evidence quality varies across studies, and many evaluations are based on modest sample sizes. The most critical limitations noted include increasing global reports of anthelmintic resistance and the fact that existing comparative evidence is lacking for certain parasite species.

Key Studies & References Nilzan (Levamisole/Oxyclozanide) Summary of Product Characteristics and Indications

Common questions about Nilzan (FAQ)

Q: What should I know about the long-term use of Nilzan?

A: Regulatory research summaries focus predominantly on the short-term effects of the medicine and the immediate period following a single treatment. Official documents note limitations in the available evidence for long-term outcomes, both for efficacy and safety, extending past the initial usage period. The evidence landscape indicates that long-term data is not as extensively documented as short-term findings.

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Q: What if Nilzan doesn't seem to be working for me?

A: Official labels state that internal parasites may develop resistance to anthelmintic medicines. This is a common factor noted in research when efficacy variability occurs. In contexts where effectiveness is a concern, official information mentions the use of a drench resistance test as a method to understand the efficacy profile in a specific population.

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Q: How is Nilzan different from other drugs in its class?

A: Nilzan is defined as a combination drug containing two distinct active components, Levamisole and Oxyclozanide. Official sources highlight that the dual mode of action involves one component causing spastic paralysis in worms and the other disrupting the energy metabolism of flukes. The combination of the two agents is associated with activity against a wider array of parasite types than either agent used alone.

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Q: Does taking Nilzan affect the ability to get pregnant?

A: Official regulatory documents indicate that the product is generally permitted for use in pregnant animals. Specific data detailing effects on fertility or the ability to conceive is not typically included in the main product label. Conditional restrictions for use in heavily pregnant animals are documented in official sources, mandating special caution.

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Q: How does the effectiveness of Nilzan change over time?

A: Official documentation indicates patterns where the effectiveness of anthelmintic drugs like Nilzan may change over time due to the documented risk of the emergence of anthelmintic resistance in parasite populations. This concept relates to the parasite's ability to tolerate the drug over successive generations.

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Q: What kinds of tests or monitoring might be needed while using Nilzan?

A: Official administration instructions define accurate determination of body weight prior to dosing as a procedural requirement for proper administration. Efficacy monitoring in research contexts focuses on outcomes like Fecal Egg Count Reduction (FECR). Monitoring for enhanced adverse effects is also noted for animals with conditions such as severe liver damage.

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Q: How quickly does Nilzan leave the body?

A: Official documents specify a Withdrawal Period—the time required before animals can be used for human consumption—to ensure drug residues are acceptable. Pharmacokinetic data suggests that the time required for the active components to be processed and eliminated from the body varies depending on the animal species being treated.

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Q: Are there different strengths of Nilzan available?

A: Yes, official information indicates that Nilzan is available in different product variants with varying names. These variants are described as having different concentration ratios of the active ingredients compared to the standard formulation.

How to Store and Dispose of Nilzan?

Nilzan (levamisole and oxyclozanide) must be stored strictly according to the official product labeling to maintain its stability and integrity.

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Storage Conditions

Requirement	Regulatory Mandate
Temperature	Store below 30 C in a cool, dry place.
Protection	Must be protected from direct sunlight and stored in a well-ventilated area.
Packaging	Keep in the closed, original container and keep the container tightly closed.
Child Safety	Keep out of reach of children (P102) and store locked up.

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Disposal Instructions

Disposal of contents and containers must be conducted as specified on the registered label (P501). It is prohibited to contaminate water, food, or feed by storage or disposal. The product's label instructs to avoid release to the environment and to retain and dispose of contaminated wash water appropriately.