The primary role of Eclipse (Abamectin, Levamisole) is used in situations involving certain distressing symptoms related to parasitic challenges facing cattle. It is commonly used to help with disease states and symptoms that create noticeable physiological strain associated with both internal and external parasite burdens, which supports general well-being and comfort.

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This combination formulation is applied across domains where additional symptomatic support is needed to address infections, including gastro-intestinal roundworms, lungworm, sucking and biting lice, cattle ticks, and buffalo fly infestations. This application contributes to easing the overall symptom load by supporting improved digestive and respiratory function and managing the symptoms related to inflammatory or irritative states on the skin.

“By using two active ingredients, this product may assist with achieving a comprehensive therapeutic approach against infections that present a significant challenge to herd health.”

The medication supports a robust level of control that is relevant for managing parasite populations that may have developed resistance to single-drug treatments. This is often used in strategic herd health programs during phases when symptoms become more noticeable or when subclinical performance impairment is a concern.

Quick Fact: Relief for Parasite Burden
Contributes to improved comfort by contributing to easing distress from external parasites and supports functional stability by managing internal worm populations.

Who can and cannot use Eclipse? focuses strictly on the population eligibility rules defined in regulatory documents for this combination antiparasitic solution. The medicine is primarily intended for adult, healthy cattle who do not meet any specific restriction or contraindication.

The official label establishes absolute prohibitions based on the animal's weight, age, and physiological status related to human food safety.

Eligibility Status	Specific Population	Restriction Basis
Contraindicated	Calves under 50 kg bodyweight	Safety and toxicity risk
Prohibited	Lactating cows or within 60 days of calving (milk for human consumption)	Chemical residue management

Beyond these absolute exclusions, the regulatory labeling identifies specific conditions that restrict use due to safety concerns. The medicine is not recommended for cattle that are severely stressed, in ill health, or dehydrated, as these states may increase the risk of toxicity. Use is prohibited in cattle that are concurrently being treated with organophosphate dips due to the risk of fatal chemical interaction documented for the Levamisole component. Use in pregnant animals is permitted but requires caution to minimize handling stress during application. This profile strictly governs who may use the medicine under regulatory standards.

Interaction Map: Interactions with other medicines and products — official regulatory information for Eclipse

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Interaction Scope

Medicinal product categories with documented interactions: Organophosphate compounds (e.g., in dips or washes).

Specific interacting medicines (if explicitly listed): Organophosphate dips.

Mechanistic basis of interactions (only if stated in label): Pharmacodynamic additive toxicity related to the Levamisole component. The Abamectin component’s systemic disposition is critically dependent on the efflux transporter P-glycoprotein (P-gp) function.

Timing-based interaction rules (if applicable): Concurrent treatment with organophosphates is restricted and, by extension of related product labels, contraindicated within 14 days.

Population-specific interaction notes (if applicable): The product must not be used on animals which are severely stressed or in ill health.

Interaction-related restrictions: Strict prohibition of co-administration with organophosphate compounds.

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Interaction Classifications (High-Level)

Interaction severity classification (as defined in official documents): Contraindicated (for co-administration with organophosphates).

Regulatory basis (EMA / FDA / etc.): Constraints specified in product information documents approved by national regulatory authorities.

Interaction-context constraints (as defined in official documents): Use is restricted based on the animal's physiological state.

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Resulting Interaction Structure

Official interaction statements:

• Co-administration with organophosphate dips is contraindicated due to the risk of a severe, potentially fatal, additive pharmacodynamic toxicity stemming from the Levamisole component.
• The safe systemic disposition of the Abamectin component is dependent on the efflux activity of the P-glycoprotein (P-gp) transporter.
• The regulatory label includes a restriction that the product must not be used on animals which are severely stressed or in ill health, defining a specific physiological state that contraindicates use.

Connection to the overall interaction profile (2–4 sentences): The regulatory interaction profile for this combination product is primarily defined by a high-severity contraindication against a specific compound class (organophosphates) due to additive toxicity. Further constraints are established by the documented transporter-mediated exposure dependence of the macrocyclic lactone component, alongside a required physiological state restriction tied to the animal's current health.

Dual Mechanism of Action: Neuromuscular Alteration

The mechanism of action for this combination product focuses on the dual-action alteration of the parasite's nervous and motor systems using two chemically distinct agents that target different receptors.

Targeting Ion Channels for Flaccid Paralysis (Abamectin)

This core mechanism involves the high-affinity binding of Abamectin to the parasite-specific Glutamate-Gated Chloride Channels ( GluCls). This interaction forces the channel to open and remain open, allowing a massive influx of negatively charged chloride ions. This leads to profound hyperpolarization of the nerve cell, electrically silencing the cell and preventing signal transmission, which results in flaccid paralysis (loss of muscle tone and movement).

Overdrive of Receptors for Spastic Paralysis (Levamisole)

The complementary mechanism is driven by Levamisole, which acts as an agonist at the parasite's Nicotinic Acetylcholine Receptors ( nAChRs) located at the neuromuscular junction. By continuously stimulating these receptors, Levamisole forces a state of persistent depolarization, overriding normal control. This causes the muscle fibers to enter a state of continuous, uncontrolled contraction known as spastic paralysis (rigidity).

Synergy Through Orthogonal Mechanisms

The mechanism is anchored in its orthogonal neuro-disruption, causing the complete and irreversible cessation of muscle function through two non-overlapping pathways. This dual-mechanism approach—flaccid paralysis via chloride channels and spastic paralysis via acetylcholine receptors—targets structurally distinct receptor sites, causing the physical expulsion of the immobile parasite.

Administration Guidelines

Eclipse is designated as a topical pour-on solution for dermal administration to cattle; its use by oral or injectable routes is prohibited. The preparation is administered as a single-dose application, with the subsequent use of the product being governed by a minimum re-treatment interval of 35 days.

Proper administration is dependent on accurate bodyweight determination. Standard practice involves weighing a representative sample of animals prior to treatment. The dose is calculated at a standard rate of 1 mL per 20 kg of body weight, and is based on the weight of the heaviest animal in the group to ensure all animals receive the minimum necessary amount. Failure to adhere to the weight-based dose calculation constitutes improper use.

Application Technique and Usage Constraints

The physical administration of the solution requires the use of the product-specific pour-on applicator supplied with the formulation, which is not interchangeable with other equipment. The calculated volume is applied in a narrow strip along the animal's backline, starting in the area between the shoulder blades. While the product is generally considered rainfast, it should not be applied to wet animals.

Mandatory population constraints govern product use: the solution must not be administered to calves under 50 kg body weight. Furthermore, it is restricted for use in cows that are actively lactating or within a 60-day period prior to calving where milk is intended for human consumption.

Research Evidence / Overview of Studies for Eclipse (Abamectin, Levamisole)

This section provides a summary of the official research structure for the antiparasitic product Eclipse, focusing on how its evidence was gathered and what aspects of its use remain under investigation. This information is intended for educational purposes only and does not contain clinical recommendations or advice.

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Evidence for Management of Gastro-intestinal Roundworm Infestations

Research explored the relationship between the active ingredients and internal roundworm infestation patterns, using Randomized Controlled Trials (RCTs) and controlled efficacy studies. These studies were designed to monitor the effect of the active ingredients on the parasite population. Researchers specifically examined outcomes related to functional imbalance by measuring Fecal Egg Counts (FEC). Findings described the difference in counts measured in the treatment groups compared to control groups.

However, research outcomes may vary based on the local parasite species and the presence of existing resistance in a specific geographic area. Furthermore, follow-up durations for these primary efficacy endpoints were typically limited to a few weeks, meaning long-term outcomes on sustained herd health are not well characterized.

Evidence for Management of Lungworm and External Parasite Infestations

Dedicated research has explored the use of the medicine’s active ingredients for internal parasites like lungworm and external challenges such as lice, ticks, and flies. For lungworm, research monitored outcomes linked to functional imbalance by examining worm counts in lung tissue. For external parasites, the primary measurement was the count of visible parasites on the skin and coat.

In trials studying external parasites, researchers monitored the systemic absorption of the Abamectin component and measured the reduction of parasite counts for sucking lice shortly after treatment. The efficacy variables of the pour-on formulation can be sensitive to factors related to field use conditions, and the duration of the effect may vary between different external parasite species.

Research Context for Parasite Resistance Management

Research explored the medicine's role as a strategy to manage anthelmintic resistance through Comparative Trials where the two-active approach was monitored alongside single-active agents in populations known to have resistance issues. Findings described patterns where parasite count reductions were measured in the combination approach and were compared to those measured in the single-active agent groups. This supports the established pharmacological rationale for utilizing two distinct mechanisms of action concurrently. However, the long-term capacity of the combination to manage future resistance development is still emerging, and sustained certainty remains low without continuous monitoring.

Key Studies & References

1. The efficacy and plasma profiles of abamectin plus levamisole combination anthelmintics administered as oral and pour-on formulations to cattle (RCT comparing formulations and actives)
2. Major veterinary combination products in the world and relevant guidance/guidelines in place (Regulatory guidance on efficacy thresholds for combinations)

Common questions about Eclipse (FAQ)

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Q: Is Eclipse available over-the-counter?

A: Eclipse is a prescription medication. This means a licensed healthcare professional must assess your health status and determine if Eclipse is appropriate for your condition before it can be dispensed.

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Q: What should I do if I miss a scheduled dose of Eclipse?

A: Information regarding missed doses of Eclipse is typically detailed in the official product labeling. It is essential to consult with your prescribing healthcare provider or pharmacist for specific guidance on managing a missed dose, as instructions may vary based on the treatment schedule and the time elapsed. They can provide advice tailored to your specific situation.

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Q: Can I suddenly stop taking Eclipse if I start feeling better?

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A: Do not stop taking Eclipse or change your dosage without first speaking to your healthcare provider. Stopping the medication suddenly may lead to a return of symptoms or other specific reactions, depending on the drug's mechanism and indication. Your doctor can advise on how to safely adjust or discontinue the treatment if necessary.

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Q: Does Eclipse cause drowsiness, and should I avoid driving while taking it?

A: Drowsiness or dizziness may be listed as potential side effects of Eclipse in the official prescribing information. Patients should be aware of how the medication affects them individually before operating machinery or driving a vehicle. If you experience these effects, it is prudent to discuss this with your healthcare provider for further guidance.

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Q: Is it safe to consume alcohol while taking Eclipse?

A: Official regulatory information often advises caution regarding alcohol consumption while taking prescription medications. Alcohol may intensify certain side effects of Eclipse, such as drowsiness, or could potentially affect how the drug works. It is best practice to discuss alcohol use with your doctor or pharmacist to understand the specific recommendations for Eclipse.

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How to Store and Dispose of Eclipse?

Storage

Eclipse should be stored at room temperature, generally between 68 F and 77 F (20 C and 25 C), away from moisture and light. Do not store it in the bathroom. Keep the medication in its original container, tightly closed, and out of the reach of children and pets. Brief excursions outside this range, from 59 F to 86 F (15 C to 30 C), are generally permissible.

Disposal

Do not dispose of Eclipse down the toilet or drain unless instructed to do so by a healthcare provider. The safest method for disposing of expired or unused medication is through a local take-back program. If a take-back program is unavailable, mix the medication with an unappealing substance, such as dirt or used coffee grounds, seal it in a plastic bag, and then discard it in the household trash. Consult your pharmacist or local waste disposal company for detailed guidance on disposal.