This medication provides therapeutic control over specific reproductive phases and conditions linked to the corpus luteum (CL).

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Controlled Regulation and Resolution

Cyclase is commonly used in breeding protocols to establish precise, managed timing for breeding procedures, such as timed artificial insemination, and for the intentional induction of parturition (farrowing or calving). It supports the process of resolving hormone-driven issues caused by the persistence of the corpus luteum (CL), which may interfere with the natural reproductive cycle. This therapeutic application may support functional stability during symptomatic phases. The drug is used in situations involving the management of conditions, including oestrus synchronization, treating uterine conditions such as pyometra and chronic endometritis, and managing functional problems like sub-oestrus.

Quick Fact: Relief for Reproductive Blockage
Primary Benefit	Supports return to normal reproductive cyclicity
Addressed Condition	Persistent Corpus Luteum (CL)
Usage Scenario	Controlled Breeding Programs

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Targeted Management of Clinical Status

The medication is therapeutically applied to achieve the controlled termination of specific reproductive states, such as early pregnancy (e.g., following mis-mating) when management requires interruption. It is also used to facilitate the expulsion of pathological contents from the uterus, including retained fetal tissue or a mummified fetus, and is used to assist with the resolution of non-viable conditions. This approach supports reproductive management in situations which, if unmanaged, may pose a risk to future reproductive health.

Regulatory References

1. NIH DailyMed overview

Who can and cannot use Cyclase?

Official regulatory documentation classifies the active ingredient in Cyclase, Cloprostenol, exclusively as a Veterinary Medicinal Product (VMP). Therefore, therapeutic use is prohibited for all human populations. The human eligibility rules are defined by the mandatory contraindications and restrictions for handlers exposed to the medication.

Eligibility Status	Officially Documented Rules
Contraindicated	Pregnant women and women of child-bearing age must not handle the product due to the documented risk of causing a miscarriage.
	Individuals with asthma or other bronchial diseases are excluded from handling due to the risk of inducing severe bronchospasm.
	Persons with a known hypersensitivity to Cloprostenol or its excipients are prohibited from contact.
Conditional Use	Handling is restricted only to licensed veterinarians and trained personnel. All permitted handlers must use impervious protective gloves and adhere to strict safety protocols.

Age and Comorbidity Eligibility: No specific therapeutic eligibility rules for pediatric, adolescent, or older adult populations are established, as the product is not licensed for human medicinal use. Restrictions for handling are based on the respiratory and reproductive status of the individual.

Interactions with other medicines and products

Official regulatory information for Cloprostenol (Cyclase) primarily documents pharmacodynamic interactions that affect the reproductive system, with no interactions documented involving major metabolic enzymes, drug transporters, food, alcohol, or supplements.

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Documented Interaction Patterns

Interacting Agent	Official Interaction Pattern	Classification & Restriction
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)	NSAIDs inhibit the body’s synthesis of prostaglandins, an effect that counteracts the action of Cloprostenol.	Prohibited Co-administration
Oxytocin	Co-administration results in an additive pharmacodynamic effect, specifically increasing effects on the uterus.	Clinically Significant Alteration
Progestogens	Co-administration results in an antagonistic pharmacodynamic effect, decreasing the luteolytic action of Cloprostenol.	Clinically Significant Alteration
Gonadorelin (GnRH)	Regulatory assessment confirms no adverse drug interaction is anticipated when used sequentially in timed protocols.	No Adverse Interaction

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The regulatory profile establishes that the product must not be combined with agents that interfere with the prostaglandin mechanism, explicitly restricting co-administration with NSAIDs. It also details the known additive or antagonistic effects that occur when Cloprostenol is co-administered with certain other reproductive hormones.

Targeting Soluble Guanylate Cyclase (sGC)

This mechanism focuses on the drug's role as a direct modulator of the intracellular enzyme soluble guanylate cyclase (sGC), primarily located within vascular smooth muscle cells. By stimulating this enzyme, the drug initiates a key molecular step in its action: the increased conversion of guanosine triphosphate (GTP) into the signaling molecule cyclic guanosine monophosphate (cGMP).

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Cellular and Physiological Modulation

This rise in cGMP activates a distinct cellular cascade, notably the protein kinase G (PKG) pathway, which leads to the phosphorylation of target proteins within the cell. This downstream signaling mediates the relaxation of vascular smooth muscle cells (vasodilation) and inhibits excessive cell growth. This mechanism contributes to the reduction of vessel constriction and the modulation of cellular proliferation in the vessel wall, resulting in sustained modulation of cellular growth and the acute relaxation of smooth muscle.

The administration of Cyclase (Cloprostenol) is defined for its specialized veterinary applications in reproductive management. The medicine is supplied as a sterile solution for injection and must be administered exclusively via the deep intramuscular (IM) route; the intravenous (IV) route is explicitly prohibited.

Dosage is specific to the target species. For example, the standard dose for cattle (cows and heifers) is 500 mu g of cloprostenol. A smaller dose of 175 mu g is typically specified for use in pigs (sows), demonstrating the need to adhere to species-specific instructions.

The frequency of administration depends on the goal of treatment. A single administration is commonly used for resolving specific conditions or for inducing parturition. Conversely, the drug is used in a two-dose regimen for synchronization protocols, where the second injection is scheduled precisely 11 days after the first to control the reproductive cycle timing.

Procedurally, administration requires the application of an aseptic technique to the injection site. Furthermore, instructions limit the use of multi-dose vials after initial access; any remaining product must be discarded after a specific period, typically 28 days, to ensure product integrity. These detailed instructions define the method for administering the medicine.

Cyclase: Recent Clinical Evidence

Clinical research on agents that modulate Cyclase enzymes, such as soluble guanylate cyclase (sGC), primarily focuses on cardiovascular and pulmonary conditions. The studied agents are generally categorized as sGC stimulators or activators, which target the nitric oxide (NO)–sGC–cyclic guanosine monophosphate (cGMP) pathway.

Efficacy Findings

• Pulmonary Arterial Hypertension (PAH): Major Phase 3 trials have investigated sGC stimulators like Riociguat in patients with PAH and chronic thromboembolic pulmonary hypertension (CTEPH). In these studies, Riociguat was assessed for its impact on exercise capacity, measured by the 6-minute walk distance (6MWD), and pulmonary vascular resistance (PVR). Trial results observed improvements in both 6MWD and PVR compared to placebo in the studied populations.
• Heart Failure (HF): The sGC stimulator Vericiguat has been the subject of research in patients with chronic heart failure and reduced ejection fraction (HFrEF). A large Phase 3 trial assessed Vericiguat against placebo on a composite endpoint of cardiovascular death or first heart failure hospitalization. The findings showed a reduction in this composite risk in the group receiving Vericiguat compared to placebo. Exploratory analyses in patients with heart failure with preserved ejection fraction (HFpEF) have also investigated improvements in health status and quality of life measures.

Safety and Tolerability

Safety profiles across these clinical trials generally indicate that sGC modulators are associated with adverse events typical of vasodilators, with hypotension (low blood pressure) being one of the most frequently reported. The incidence of serious adverse events has been observed to be comparable between the treatment groups and the control groups in most randomized controlled trials.

Common questions about Cyclase (FAQ)

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Q: Is Cyclase the same as the drug my friend is taking for the same condition?

Official regulatory documents classify Cyclase (Cloprostenol) strictly as a Veterinary Medicinal Product (VMP). This means the medicine is not approved for therapeutic use in all humans. Any drug used by a friend for a human health condition would be a different, licensed product.

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Q: Why did my doctor prescribe Cyclase instead of another option?

Since Cyclase is not licensed for human use, it is therefore not prescribed for people. It is an official Veterinary Medicinal Product intended solely for use in animals.

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Q: How quickly should I expect to see an effect from Cyclase?

Studies and official pharmacological information describe Cyclase as a potent agent intended to produce its primary effect—the regression of the corpus luteum—shortly after administration in the target species. This effect is a swift, precise pharmacological action to control the reproductive cycle.

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Q: Is it normal to feel a bit nauseous when first starting Cyclase?

Nausea is not listed in the official safety profile. The documented gastrointestinal effects are transient scouring (diarrhea) in the animal patient. The product information details adverse reactions based on its therapeutic use in animals.

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Q: Can Cyclase be taken with over-the-counter pain relievers like ibuprofen?

Official documentation restricts co-administration with Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), which includes ibuprofen, as they may counteract the drug's intended action. This is one of the documented interactions detailed in the product information.

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Q: Are there any specific foods or drinks I need to avoid while on Cyclase?

Regulatory information documents no specific interactions involving major metabolic enzymes, drug transporters, food, or alcohol. The documented interactions primarily involve other specific reproductive hormones.

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Q: Will Cyclase help with all symptoms of my condition?

Cyclase is classified as a powerful luteolytic agent, meaning its primary, specific function is to induce the controlled breakdown of the corpus luteum in the ovary. Its purpose is focused on the targeted action of controlling a specific phase of the reproductive cycle.

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Q: Is Cyclase considered a long-term treatment?

Official guidance indicates its use is over a short, defined period for reproductive management. Administration is standardized to a single injection or a two-dose regimen given precisely 11 days apart for synchronization protocols.

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Q: Is Cyclase addictive or habit-forming?

Official documentation contains no information regarding potential for abuse or habit-forming behavior. Cyclase (Cloprostenol) is not classified as a controlled substance.

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Q: Does Cyclase affect my mood or energy levels?

The documented adverse event list does not include psychiatric or neurological disorders such as changes in mood or energy levels. The safety profile is established for its specific use as a luteolytic agent.

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Q: Does Cyclase cause fatigue or sleepiness?

The documented adverse event list does not include effects on the central nervous system such as fatigue or sleepiness. The safety profile is established for its specific use as a luteolytic agent.

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Q: Is Cyclase a medication that treats the cause or the symptoms?

The drug is classified as a luteolytic agent. This mechanism directly addresses a specific physiological structure—the corpus luteum—and its function, allowing for pharmacological control over the reproductive cycle.

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Q: Does Cyclase work better if taken in the morning or evening?

Official administration instructions define the mandatory route and frequency of use but do not specify a preference for morning or evening administration based on the time of day.

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Q: Are there any dietary restrictions mentioned in the official labeling for Cyclase?

Official regulatory information documents no interactions involving major metabolic enzymes, drug transporters, food, or supplements.

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Q: What is the difference between an adverse event and a side effect?

Official guidance defines an adverse event as any unfavorable or unintended sign or symptom associated with the use of a drug. A side effect often refers to a known or expected effect that is secondary to the main therapeutic action.

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Q: What are the official patient information leaflets for Cyclase?

Since Cyclase is a Veterinary Medicinal Product, due to its classification, there are no 'patient information leaflets' intended for human patients. Official product information is contained in regulatory documents like the Summary of Product Characteristics (SmPC) or the FDA Label for Veterinary Use.

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Q: What are the main things doctors consider before prescribing Cyclase?

The official criteria for administering Cyclase include the intended reproductive goal for the animal patient, the confirmation of a responsive reproductive structure (corpus luteum), and the exclusion of animals with pre-existing spastic diseases of the respiratory or gastrointestinal tracts.

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Q: Is Cyclase covered by most insurance plans?

As a Veterinary Medicinal Product (VMP), Cyclase is not listed on human prescription drug formularies and would not be covered by human health insurance plans.

The storage and disposal of Cloprostenol (Cyclase) must adhere strictly to official regulatory requirements to ensure product stability and safety.

Storage Requirements

The product must be kept out of the sight and reach of children and stored at controlled room temperature, typically 20 C to 25 C, and protected from light and excess moisture.

Keep the medicine in its original container and ensure the vial remains tightly closed. The labeling specifies a limited post-broaching shelf-life, requiring the product to be discarded a defined number of days (e.g., 28 or 180) after the initial opening, depending on the formulation.

Disposal Instructions

Unused or expired product and all associated waste material must be disposed of in accordance with local regulations. It is explicitly mandated to avoid release to the environment and prevent contamination of waterways. Used needles and syringes (sharps) must be immediately placed in a designated sharps container.