Quick Facts

• May assist in temporary or permanent management of the reproductive cycle in female dogs and cats.
• May be administered to help prevent the clinical signs associated with false pregnancy in female dogs.
• May be suitable for supporting the management of feline miliary dermatitis in cats.
• Used in female ferrets to manage prolonged periods of estrus (heat).

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What Delvosteron Treats: Main Uses and Benefits

Delvosteron (proligestone) is a medication used in veterinary practice for a variety of indications in female dogs, cats, and ferrets. Its uses focus primarily on supporting the management of the reproductive cycle and certain related conditions.

In dogs and cats, it is suitable for use in the postponement or suppression of the estrus cycle (heat or calling). This offers an option for temporary reproductive management in these species. The product is also employed to help alleviate the nervous signs and lactation that are associated with false pregnancy in bitches.

For cats, Delvosteron may be included as a supporting measure in the management of feline miliary dermatitis (miliary eczema).

In ferrets, the drug is suitable for administration to help prevent complications that may arise from prolonged periods of estrus, such as potential uterine infections and bone marrow suppression. This use supports the overall health of the female ferret when the heat cycle is persistent.

Regulatory References

1. Summary of Product Characteristics

Who Can and Cannot Use Delvosteron?

Delvosteron (proligestone) is officially indicated for use exclusively in female dogs, cats, and ferrets as defined by governmental regulatory documents. Its eligibility is strictly determined by the animal's reproductive status, age, and health history, establishing clear boundaries for its use.

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Populations That Must Not Use (Contraindicated)

Use of the medicine is formally contraindicated and prohibited in several key situations. The product must not be administered to pregnant animals under any circumstances. Furthermore, it is prohibited in bitches who have been in oestrus (heat) for three days or longer. Regulatory labeling also prohibits use in female dogs that have already been treated for the current false pregnancy with other estrogens or progestogens.

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Eligibility Restrictions and Cautions

Specific population restrictions apply to certain age groups and clinical conditions. Medication is not generally advised for female dogs before their first oestrus (pre-puberty), and use at the first oestrus is not normally recommended. Delvosteron must be used with caution in diabetic animals, as regulatory guidance requires careful monitoring of glucose levels following administration. If a false pregnancy recurs after a second dose, further hormonal treatment is officially not recommended.

Interactions with other medicines and products

Official regulatory information for Delvosteron (proligestone) details specific interaction constraints regarding co-administered medicinal products, primarily focusing on hormonal, metabolic, and supportive agents.

Documented Interaction Restrictions

The product is subject to a contraindication-related restriction regarding concurrent hormonal therapy. Co-administration with oestrogens or other progestogens is officially prohibited when these substances have been used to treat the current episode of false pregnancy in bitches.

Metabolic and Pharmacodynamic Considerations

A specific metabolic interaction is documented concerning the use of Insulin. Delvosteron administration may lead to an increased insulin requirement in diabetic animals. This is an official use-with-caution scenario requiring careful observation of sugar levels in the animal for a defined period after dosing.

Additionally, a pharmacodynamic constraint exists concerning Glucocorticoids. The official product profile suggests that the co-administration of glucocorticoids may be necessary if an animal receiving Delvosteron for permanent postponement of heat is subsequently subjected to a significant physiological stressor, such as excessive trauma, stress, or major surgery.

Delvosteron, which contains the progestin proligestone, exerts its mechanism of action by acting as an agonist at the intracellular progestin receptors (PRs). Upon systemic absorption, proligestone distributes to target cells in tissues responsive to progestogens, including the pituitary, hypothalamus, and uterus. The lipophilic proligestone molecule passively diffuses across the cell membrane and binds to the PR in the cytoplasm or nucleus.

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Ligand binding induces a conformational change in the receptor, leading to dimerization and translocation of the PR complex into the nucleus (if binding occurred in the cytoplasm). Within the nucleus, the activated receptor dimer functions as a transcription factor, binding to specific DNA sequences known as Progesterone Response Elements (PREs) in the promoter regions of target genes. This binding modulates the rate of gene transcription, leading to an altered expression profile of specific proteins, which is the genomic action. Additionally, progestins can elicit rapid, non-genomic effects by binding to membrane-associated PRs or interacting with intracellular signaling molecules, such as kinases, thereby modulating existing signaling cascades like the MAPK pathway.

At the system level, this transcriptional and non-transcriptional modulation results in the suppression of gonadotropin release from the pituitary, specifically Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH). This pituitary-level action reduces the hormonal stimulus for ovarian follicular development and maturation. The overall physiological consequence is a direct modulation of the hypothalamic-pituitary-gonadal (HPG) axis.

Delvosteron is a veterinary medication presented as an Aqueous Suspension for Injection, containing Proligestone 100 mg/ml. The administration is restricted to the subcutaneous route (under the skin) in dogs, cats, and ferrets.

Proper administration requires adherence to specific procedural steps. The vial must be shaken well before use to ensure the suspension is uniform. The injection should be delivered using sterile equipment and placed in specific anatomical areas, such as the neck or inside of the thigh. Procedural guidance specifies that the product must not be deposited intradermally or into scar tissue, and the injection site should be massaged afterward to aid product dispersion.

The dosing regimen is cycle-dependent and non-variable. For example, in dogs undergoing permanent postponement of the estrous cycle, the administration follows a structured, multi-phase schedule: the first two injections are given 3 months apart, the third is given 4 months later, and subsequent maintenance injections are given at regular 5 month intervals. For suppression of an existing heat cycle, a single injection is administered in early pro-oestrus. For conditions like feline miliary dermatitis, a dose of 1.5 ml may be repeated 14 days later, with maintenance sometimes required at 4 month intervals. The preparation, delivery technique, and precise timing intervals are established for the medication's intended use.

Research Evidence / Overview of Studies for Delvosteron

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Evidence for Estrous Cycle Management in Dogs and Cats

Research examined proligestone for use in exploring the temporary postponement and the complete suppression of estrus (commonly known as heat or calling). Research has primarily taken the form of field clinical trials across various veterinary settings, alongside non-comparative clinical studies.

Researchers examined changes in the outcomes related to physical discomfort and behavioral signs of estrus. They also monitored the duration of the artificially induced period of ovarian quiescence and the time interval until the next estrous cycle naturally returned after administration. For dogs, long-term studies exploring extended-duration use described patterns where the interval between the last injection and the return of heat was observed in some studies to be within a 6–7 month range.

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Evidence for Managing Specific Reproductive Conditions

Research has explored the product's application in conditions characterized by fluctuating or episodic manifestations linked to hormonal shifts, such as false pregnancy in dogs and complications arising from prolonged estrus in ferrets.

Research on False Pregnancy in Dogs

Clinical trial results was evaluated in female dogs (bitches) presenting with overt signs of false pregnancy (pseudopregnancy). Studies focused on outcomes related to systemic or functional imbalance by examining changes in both behavioral manifestations (like nervousness and nesting behaviors) and physical signs (like lactation). The outcomes reflecting daily functioning or activity level are assessed based on clinical and subjective assessment of signs, which is a key research constraint.

Research on Prolonged Estrus in Ferrets

Comparative studies examined the duration of induced anoestrus and the potential for preventing certain outcomes monitoring physiological strain or stress that can be associated with prolonged estrus. Comparative research explored patterns in the average duration of ovarian quiescence, which was approximately 99 days in one study.

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What Is Still Uncertain About Delvosteron

The evidence highlights what is known — and what is still uncertain. Comparative evidence is lacking for certain uses, as few large-scale randomized controlled trials comparing proligestone to placebo or non-hormonal standard veterinary management are widely detailed in the public domain. There is limited information for long-term outcomes regarding the effects of repeated administration over many reproductive cycles, including the consistency of return to fertility.

Key Studies & References

1. Delvosteron 100 mg/ml Suspension for Injection. - Summary of Product Characteristics (SPC)
2. Comparison of four treatments to suppress ovarian activity in ferrets (Mustela putorius furo)

Common questions about Delvosteron (FAQ)

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Q: What are the most common reported side effects associated with Delvosteron?

According to official product literature on adverse reactions, some of the common reported effects include a temporary feeling of lethargy (sluggishness). A transient (temporary) increase in appetite associated with weight gain is also a frequently reported effect.

Q: Is weight gain or increased appetite a frequently reported expectation when using Delvosteron?

Regulatory information indicates that a transient increase in appetite may be seen while using the product. This increase in appetite is associated with the potential for weight gain in some animals, according to official adverse reaction reports.

Q: Are there any documented, rare but serious side effects of Delvosteron?

The official adverse reaction list documents several serious effects associated with the drug. These include the development of uterine changes (such as pyometra) and certain mammary gland disorders. Additionally, in very rare cases, a sudden, severe allergic reaction called a systemic anaphylactic reaction may occur.

Q: Does Delvosteron typically cause any local reactions at the site of injection?

Official product information indicates that some pain may be noticed immediately following the injection. Additionally, the regulatory documents note that slight local reactions may occasionally develop, which can include temporary changes to the skin like thinning, discoloration, and hair loss at the injection site.

Q: Is Delvosteron classified as a short-term or long-term treatment option?

According to official use guidelines, Delvosteron is used for both short-term and long-term needs. This includes single injections for temporary cycle suppression, as well as repeat injections given over an extended period for permanent postponement of cycles.

Q: What information is available about the effects of Delvosteron on liver function?

Official guidance on eligibility is specific regarding liver function. Regulatory documents state that Delvosteron is contraindicated in any animal with a history of liver disease. The term 'contraindicated' describes conditions where the product should generally not be administered.

Q: What are the contraindications for using Delvosteron, based on patient history?

Regulatory documents state that a history of reproductive tract disease, mammary disease, or liver disease represents a contraindication for use. The drug is also contraindicated when other hormonal treatments have already been used to manage the current episode of false pregnancy.

Q: Can individuals with a history of certain types of tumors use Delvosteron?

Official warnings state that use is contraindicated if there is any history of mammary disease or reproductive tract disease. This information is based on the official guidelines for use and eligibility.

Q: Is Delvosteron suitable for use in patients who are planning to conceive in the future?

Official guidance advises that the use of this drug is not recommended for animals intended for future breeding. This is due to the drug's intended action of cycle suppression.

Q: What is the typical timeline for when the effects of Delvosteron might be noticed?

Official information describes the typical timeline when the product is used for cycle suppression. In these cases, the visible signs of heat, such as vulval swelling or bleeding, generally fully regress within 5 days of receiving the dose.

Q: What information is available regarding the return to a pre-treatment state after stopping Delvosteron?

Official clinical literature indicates that the return to the pre-treatment estrous cycle is very variable. Depending on the cycle stage when the drug was first administered, the return to a normal state may potentially resume after days, weeks, or months.

Q: Are there specific age groups or populations for whom Delvosteron is not typically advised?

Official prescribing information indicates that the medication is not generally advised for use before an animal has experienced its first oestrus (heat cycle).

Q: Are there any studies examining the long-term safety profile of Delvosteron?

While specific studies are not referenced in the general summaries, the regulatory label describes dosing regimens for the permanent postponement of heat. It also specifies adverse reactions associated with long-term use, such as uterine changes and mammary gland disorders, suggesting safety has been examined in this context.

Q: Can Delvosteron affect the results of general blood or laboratory tests?

Official warnings confirm that the drug can affect certain lab values. The regulatory label specifically advises that in diabetic animals, careful observation of blood insulin levels and urine sugar levels is indicated after dosing due to a possible interaction.

Q: What are the documented signs that the medicine may not be working as expected?

The official warnings document signs that the product may not be working as intended. These signs include the duration of postponement being shorter than anticipated, or the failure of physical signs of heat (like vulval swelling) to fully regress within five days of a suppression injection.

Q: Is it normal to feel temporary lethargy or a change in energy levels after an administration?

Regulatory adverse reaction reports state that a temporary feeling of lethargy (sluggishness or decreased energy) may be seen in some animals treated with the product. This is a recognized, but non-serious, reported effect.

Q: How is the safety of Delvosteron described for use during pregnancy or lactation?

Official regulatory documents state that use of the drug is not recommended during pregnancy. Furthermore, the handling instructions specify that administration of the product by individuals who are pregnant or trying to get pregnant is to be avoided due to safety concerns.

Q: Is there a risk of developing a temporary intolerance or allergy to Delvosteron?

Regulatory documents acknowledge a risk of developing a temporary intolerance or allergy. The product information states that in very rare cases, a localized or systemic (body-wide) allergic reaction known as an anaphylactic reaction may occur.

Q: What are the ingredients in Delvosteron besides the active pharmaceutical component?

The official product label describes Delvosteron as a white to off-white, aqueous (water-based), sterile suspension for injection. The active ingredient is Proligestone. While the full list of inactive components is not provided in general summaries, the regulatory documents confirm its pharmaceutical form as a specialized suspension.

The storage and disposal of Delvosteron (proligestone suspension for injection) must adhere strictly to regulatory requirements to maintain product integrity and safety.

Official Storage Conditions

Item	Requirement
Temperature	Store below 25 C; do not refrigerate or freeze.
Protection	Keep the vial in the outer carton to protect the contents from light.
Child Safety	Store out of the sight and reach of children.

Stability and Disposal

The product's unopened shelf-life is generally 3 years. Once the vial is opened for the first time, the medicine must be used immediately, and any remaining product should be discarded. Unused Delvosteron and waste materials must be disposed of in accordance with local regulations, with an explicit restriction that it must not contaminate watercourses.