Eclipse E

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Eclipse E

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Medically reviewed

Rosario Oropesa

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Eclipse E

Property Description
Active Ingredients Eprinomectin and Levamisole
Form Pour-on solution (Topical)
Pharmacological Class Endectocide and Anthelmintic
Common Use Broad-spectrum parasite control in cattle
Origin Derived (Semisynthetic/Synthetic)

What is Eclipse E and What Class of Medicine is It?

Eclipse E is a specialized veterinary medicine defined as a combination drug used to manage parasitic infections in livestock, primarily cattle. It is dually classified as an anthelmintic and an endectocide, a term used to describe products that act against both internal parasites (endoparasites) and external parasites (ectoparasites) in a single formulation. The Eprinomectin component is a semisynthetic compound derived from the avermectin family and is recognized for its efficacy against numerous parasite species, serving as a solution for comprehensive parasite management.


Composition, Physical Form, and Application Type

The medicine is composed of two principal active ingredients: Eprinomectin and Levamisole, and is prepared as a non-aqueous pour-on solution for topical administration. Eprinomectin is a macrocyclic lactone derivative, while Levamisole is an imidazothiazole derivative recognized for its specific anthelmintic effects. The unique feature of the pour-on solution is that it facilitates swift and simple external application, avoiding the need for injection or oral dosing. The compounds are dissolved in an organic solvent-based solution designed for effective absorption through the animal's skin, ensuring systemic delivery.


What is the General Purpose of the Eprinomectin and Levamisole Combination?

The primary purpose of combining Eprinomectin and Levamisole is to achieve robust, broad-spectrum control over persistent nematode and ectoparasite infestations. This formulation is frequently used as part of a strategic parasite control rotation in cattle to manage resistance risks. Combining agents with different modes of action can target broad and overlapping spectra of gastrointestinal nematodes, achieving a notable synergistic effect. This indicates that the combination is intended to overcome efficacy challenges and ensure effective clearance of a wide array of parasites in treated cattle, supporting animal health and productivity.

What side effects are possible with Eclipse E?

Adverse Reactions and Official Safety Classifications

The safety profile for this Eprinomectin and Levamisole combination product is formally categorized by regulatory bodies based on the frequency and the physiological system affected.

Classification System-Organ Class Involved
Common Skin and subcutaneous tissue disorders (Local, transient reactions at the application site and transient discomfort immediately following application).
Uncommon Nervous system disorders (Neurological signs such as tremors, salivation, or mydriasis, which are generally associated with systemic exposure to the active ingredients).
Rare General disorders (Severe systemic hypersensitivity, including anaphylactoid reactions).

Serious adverse reactions, while rare at therapeutic doses, are documented by regulatory authorities. These include signs of severe systemic toxicity, such as convulsions, blindness, or respiratory failure, typically observed only when the recommended therapeutic dose is significantly exceeded. Anaphylactoid reactions and signs of central nervous system (CNS) toxicity are explicitly noted as potential risks in official documents.

Regulatory Safety Restrictions and Considerations

The official labeling includes mandatory constraints to ensure appropriate use:

  • Non-Target Species Toxicity: The product is strictly not for administration to unapproved animal species (e.g., dogs and cats), as macrocyclic lactones present a significant, high-risk safety concern, potentially leading to fatal toxicity in these animals.
  • Population Restriction: Use is contraindicated in very young calves, specifically those less than eight weeks of age, as defined by national regulatory agencies.
  • Hypersensitivity: The product is contraindicated in any animal with a known history of hypersensitivity to Eprinomectin, Levamisole, or the formulation's excipients.

These official safety statements structure the risk profile by drawing a clear distinction between expected, minor local effects and the high-consequence systemic risks tied to inappropriate species or age use.

Overdose and Emergency Response

Overdose Map: Overdose and when to seek help — official regulatory information for Eclipse E

Overdose scope

Overdose scope Regulatory Statement
Documented overdose presentations Presentation includes a neurotoxicity profile involving tremors, ataxia, convulsions, sedation, and the risk of coma or collapse. Other manifestations include respiratory distress, emesis, and nausea.
Physiological systems affected (as stated in label) Affected systems include the Central Nervous System (CNS), Respiratory System, Gastrointestinal System, and Hematopoietic System (risk of agranulocytosis).
Dose-related or exposure-related factors (if applicable) Toxicity testing for the Eprinomectin component has indicated a margin of safety up to five times the recommended dose.
Population-specific overdose notes (if applicable) Regulatory documents note a risk of severe neurological toxicosis in populations with the MDR1 gene mutation. Contact should be avoided during pregnancy or while nursing due to a suspected risk of harm.
Emergency-response statements (as written in official documents) The official protocol is to Rinse mouth and NOT induce vomiting in the event of accidental swallowing. Medical advice is required when symptoms persist or in all cases of doubt.
When immediate medical help is required (label-derived phrasing only) Regulatory guidance mandates to Call a Poison Center/doctor immediately following accidental ingestion or when feeling unwell.

Overdose classifications (high-level)

Classification Regulatory Statement
Severity classification (as defined in official documents) Overdose risk includes potential severe systemic physiological stress leading to outcomes such as prostration, collapse, and death.
Regulatory basis (EMA / FDA / etc.) Regulatory overdose information is derived from the Summary of Product Characteristics (SmPC), FDA Prescribing Information, and Official Safety Data Sheets (SDS).
Overdose-context constraints (as defined in official documents) No specific antidote has been identified for either active component. Management is defined as symptomatic and supportive. Prolonged medical observation may be indicated.

Resulting overdose structure

Official overdose statements:

  • Overexposure is documented to result in CNS effects, including tremors, ataxia, and the risk of convulsions or coma.
  • Coma, collapse, and death are listed as potential severe or life-threatening outcomes.
  • Regulatory guidance mandates to call a Poison Center/doctor immediately in the event of accidental ingestion.
  • No specific antidote has been identified; official management is strictly symptomatic and supportive.

Connection to the overall overdose profile (2–4 sentences): The regulatory documents define the overdose profile primarily through a neurotoxicity risk and the potential for systemic escalation to severe outcomes, necessitating immediate medical intervention. This necessity is underscored by the official statement that no specific antidote is known, thus making supportive care and monitoring the only documented course of action.

Therapeutic Uses of Eclipse E

What Eclipse E Treats: Main Uses and Benefits

The primary therapeutic function of Eclipse E generally provides support that helps manage a range of parasites in cattle, playing a role in addressing both internal and external parasitic issues. The therapeutic role is defined by its use in conditions involving various parasitic infestations. It is relevant when supportive symptom management is appropriate to ease the physiological strain associated with heavy infestation.


This treatment is applied in addressing symptom clusters linked to internal parasites, such as gastrointestinal and pulmonary nematodes, and external issues caused by mange mites and lice. It supports the easing of symptoms related to systemic imbalance, including parasitic diarrhea and coughing. This dual action is generally considered relevant for use as a strategic tool in herd health programs where additional management of discomfort from a wide array of parasitic threats is required.

“The medication contributes to improved day-to-day comfort during symptomatic periods by alleviating the intense irritation and systemic strain caused by infestation.”

By clearing the underlying parasites, the treatment assists with maintaining functional stability and supports general well-being related to growth, helping to reverse conditions characterized by systemic physiological stress, reduced weight gain, and inefficient feed conversion.

Quick Fact: Relief for Irritation
The treatment helps address symptom clusters related to external parasitic activity, is relevant for easing intense itching and rubbing behavior caused by mites and lice.

Regulatory References

  1. NIH DailyMed overview of Eprinomectin

Eligibility and Restrictions for Use

Eligibility for the pour-on medicine Eclipse E is strictly defined by regulatory documents, focusing on specific populations within the target species, cattle. Use is permitted across the approved species, including beef and dairy cattle of all ages, pregnant cows, and breeding bulls. The medicine’s safety has been established for use in lactating dairy cattle, with a documented zero-hour milk discard requirement.

However, the medicine is contraindicated in several specific populations. It must not be used in calves intended to be processed for veal, a prohibition put in place to prevent violative residues. Furthermore, the product is contraindicated in any animal species other than cattle, due to the risk of severe adverse reactions in non-target species.

Eligibility is subject to conditional restrictions. The medicine must be applied only on healthy skin and is strictly limited to the pour-on route. When treating cattle infected with Warble fly larvae, treatment must be administered at a specific time of year to avoid adverse reactions, making use conditional.

What should I know about interactions with other medicines?

Eclipse E Interactions with other medicines and products

Regulatory documentation for this pour-on solution establishes interaction constraints that span three primary categories: mandatory separation requirements, restrictions based on pharmacodynamic reinforcement, and pharmaceutical incompatibility rules. This information defines the necessary administration constraints.

Interaction Restrictions and Timing Requirements

Co-administration with Organophosphorous compounds and diethylcarbamazine citrate is explicitly prohibited. The official regulatory label requires a strict 14-day separation period (before or after) administering either of these substances. Beyond this mandatory timing rule, concomitant use should be avoided with other medicines, including chloramphenicol, certain muscle relaxants, piperazine, and phenylbutazone.

Pharmacodynamic and Physical Constraints

The product carries a documented theoretical risk of enhanced toxic effects when administered alongside substances that share a similar profile of action, such as nicotine-like compounds (e.g., pyrantel) or other cholinesterase inhibitors. This effect is formally classified as a pharmacodynamic interaction. Additionally, a pharmaceutical incompatibility rule is strictly noted: the product must not be physically mixed with any other veterinary medicinal products. This restriction prevents the alteration of stability and systemic exposure. The label also notes that overall interaction relevance may be heightened in animals experiencing severe stress or ill-health.

Mechanism of Action

️ Ontology: How Eclipse E Works — Mechanism of Action

The mechanism of Eclipse E relies on a dual, coordinated action on distinct neurological pathways in parasites, leading to two distinct forms of paralysis.


Targeted Paralysis Through Chloride Channel Agonism

The Eprinomectin component exerts its effect by acting as a high-affinity agonist at the parasite's Glutamate-gated chloride channels ( GluCl). This interaction forces the channels to remain open, causing a continuous influx of chloride ions that results in severe hyperpolarization of nerve and muscle cells. This hyperpolarization blocks all necessary signal transmission, leading to sustained flaccid paralysis and inhibition of the parasite's feeding apparatus.


Neuromuscular Overstimulation via Nicotinic Receptor Agonism

Conversely, Levamisole functions as an agonist at the parasite's Nicotinic Acetylcholine Receptors ( nAChRs) (L-subtype) at the neuromuscular junction. This persistent activation causes the muscle cell membrane to sustain depolarization, leading to uncontrolled and uncoordinated nerve firing. This results in spastic (rigid) paralysis, which also results in sustained functional immobilization of the target organism.


Synergistic Dual-Action Neuromuscular Blockade

The combination of mechanisms—one leading to flaccid paralysis and the other to spastic paralysis—provides a dual-action neuromuscular blockade. This strategy targets two fundamentally different pathways ( GluCl and nAChR) crucial for parasite motility and function. The mechanistic diversity is utilized against parasite strains that may exhibit resistance to a single class of agents.

Dosage and Administration Information

How to use Eclipse E

Eclipse E, a combination of Eprinomectin and Levamisole, is intended for topical application only, delivered as a pour-on solution to the animal’s external surface. The administration is non-oral and non-injectable, as the formulation is designed for absorption through the skin.


Administration Protocol

The usage protocol involves weight-based and technique-specific requirements.

Instruction Detail
Route of administration Topical (Pour-On). Must not be given orally or by injection.
Dosing schedule Dose volume is precisely calculated based on the animal's measured body weight (BW). The dose must be complete.
Frequency A single application is administered per treatment course.
Application technique Applied as a narrow strip along the backline, running from the withers to the tailhead.
Special conditions Must be applied to dry, healthy skin using a calibrated dosing device.

Use Protocol and Population Adjustments

The use of Eclipse E requires a high degree of precision in its administration. The total required volume must be accurately measured and delivered using a calibrated dosing device. Dosing is applicable to all cattle populations and is determined by body mass; when treating groups, the dose is based on the heaviest animal to prevent underdosing. This single-course treatment is integrated as an intermittent and strategic component within a larger parasite control program.

Recent Clinical Evidence

Eclipse E: Recent Clinical Evidence

This section provides an overview of the types of scientific research that was studied for the ingredients in Eclipse E, focusing on the design of the trials, the outcomes that research examined, and the areas where long-term effects are not fully established. This summary is for informational purposes only and is not medical advice.


Evidence for Research Exploring Internal Parasite Patterns

The primary research for this medicine has included Randomized Controlled Trials (RCTs) and Controlled Efficacy Studies exploring the combination against gastrointestinal and pulmonary nematodes (internal roundworms and lungworms). Research examined primary outcomes consisting of measurements of parasite infection and overall animal productivity metrics like weight gain. In these controlled settings, findings describe patterns where measurements of parasite numbers in treated groups were noted to be different from control groups. Trials also monitored the duration of measured response against the primary target species.


Evidence for Research Exploring External Parasite Patterns

The research base includes Controlled Efficacy Studies and RCTs designed to assess the topical application against external parasites like lice and mange mites. Studies explored reducing the physical presence of these parasites and monitored outcomes related to physical discomfort. Findings describe patterns where measurements of parasite counts were lower in the treated groups, alongside observations of the evolution of symptoms linked to inflammatory or irritative states.


Long-term Follow-up, Special Populations, and Uncertainties

Research explored the measured response in Beef and Dairy Cattle across different age groups, including calves and animals with anthelmintic resistance patterns. However, evidence is limited regarding sustained impact over long-term outcomes exceeding two months. Follow-up durations were limited in many core efficacy studies, meaning the full durability of the response remains an area where evidence is limited. A major research gap is the limited availability of data detailing the long-term outcomes and the durability of the response for periods extending beyond primary regulatory follow-up. Research related to the rapidly changing nature of anthelmintic resistance is ongoing.

Key Studies & References DailyMed/FDA Drug Label Information for Eprinomectin Pour-On Solution (General Therapeutic Uses)

Frequently Asked Questions (FAQ)

Common questions about Eclipse E (FAQ)

Q: Is Eclipse E considered a safe medication to take long-term?

Regulatory documents provide information on the safety profile of the medication. They describe a favorably described safety profile for its intended use in cattle. The medicine may be used across various classes of cattle, including pregnant and lactating cows.


Q: Does taking Eclipse E require any special monitoring by a doctor?

The official instructions emphasize the need for proper administration technique. They advise on the importance of accurate dosing based on the animal's current body weight and require the use of a properly calibrated dosing applicator to ensure the intended volume is applied.


Q: What age range is Eclipse E approved for?

According to official product information, Eclipse E is indicated for use in beef and dairy cattle of all ages, including pregnant and lactating cows. However, it is explicitly not for use in calves intended for veal. Eligibility criteria for all animals are defined in regulatory documents.


Q: What if I take too much Eclipse E by accident?

Regulatory warnings address accidental human exposure to the product. They advise that if accidental ingestion or eye exposure occurs, the person should seek immediate medical advice. Immediate contact with a doctor or poison control center is advised in regulatory documents.


Q: Is it possible for Eclipse E to stop working after a while?

Official labeling acknowledges that resistance can develop to any drench (medication) over time. For this reason, official labeling suggests consultation with a veterinarian to develop a comprehensive, strategic parasite control program.


Q: How quickly does Eclipse E usually start to work?

The medication's mechanism involves a dual, coordinated action on distinct neurological pathways in parasites. The active ingredients bind to nerve and muscle cells, causing paralysis and death of the target organism.


Q: How long does the effect of one dose of Eclipse E last?

Studies and official information on the residual activity indicate that the product is described as controlling re-infection by major internal parasites for up to 28 days. It maintains effectiveness against horn flies for at least 7 days after application.


Q: Is Eclipse E the same as the medication I saw advertised under a different name?

The official regulatory label identifies the active ingredients in this medicine as Eprinomectin and Levamisole. A person may reference the label of any other product to see if it contains these same two active ingredients.


Q: Is Eclipse E a brand name or a generic name?

Eprinomectin and Levamisole are the established non-proprietary, chemical names for the substances in the product. The official label uses these names to identify the primary components.


Q: Has Eclipse E been approved in other countries besides the US?

The main active ingredient, Eprinomectin, is accepted by international authorities. It is subject to regulatory approval for use in cattle by the regulatory authorities of the United States and over fifty other countries worldwide.


Q: Is there a generic version of Eclipse E available?

Generic versions of the main active ingredient are available in the market. The specific availability of a generic version of the combination product depends on local regulatory approvals and patents.


Q: Is there a black box warning associated with Eclipse E?

The official product information contains a prominent warning containing a restriction against use in unapproved animal species, such as dogs and cats. This is because such off-label use may result in severe adverse reactions, including fatalities.


Q: What is the typical expectation for symptom improvement while using Eclipse E?

Official documents note that effective treatment and control of parasites is associated with positive outcomes related to animal productivity. This includes outcomes such as improved herd performance, additional weight gain, and better overall health.


Q: Is Eclipse E available over the counter?

According to federal regulations, this product is a prescription drug. Federal law restricts its use to a licensed veterinarian or on the order of a licensed veterinarian.


Q: Does Eclipse E show up on a standard drug test?

When used precisely according to the label instructions, the product has a zero-day meat withdrawal period. It also has a zero-day milk discard period for dairy cattle, meaning no measurable residues are expected in milk or meat.


Q: Are there any non-drug interactions listed for Eclipse E, like sunlight exposure?

The product is manufactured with a weatherproof formula. This design indicates that the formula is intended to maintain efficacy regardless of environmental exposure, such as rain or sun, after application.

How should Eclipse E be stored and disposed of?

The official regulatory profile for Eclipse E (Eprinomectin/Levamisole Pour-on Solution) defines specific storage and disposal requirements.

Storage Requirements

Store the pour-on solution at or below 30 C and do not freeze the container. It must be kept in the original container with the lid tightly closed and stored protected from light. Adhere strictly to the labeled shelf life after first opening the container. Keep the product out of the sight and reach of children.


Disposal Instructions

Disposal of unused or expired product must be done in accordance with local requirements for hazardous waste. Regulatory documents classify the ingredients as extremely dangerous to aquatic life; therefore, the product must not be disposed of via wastewater or allowed to contaminate surface water.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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