Alizin for Dogs - Uses and Side Effects

Laura García Ortiz
By Laura García Ortiz, Veterinarian specialized in feline medicine. February 19, 2024
Alizin for Dogs - Uses and Side Effects

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Alizin injection for dogs is a veterinary medicine which is indicated for use as an abortifacient. This means it is a drug which is marketed to induce an abortion of her fetuses in a pregnant dog. If administered shortly after copulation, it can prevent the implantation of the fertilized embryo and subsequent pregnancy. If the embryo is already implanted, it can cease the further development of the fetuses. The active ingredient of Alizin is aglepristone, a steroidal antiprogestogen whose mechanism prevents the action of progesterone by blocking its receptors.

At AnimalWised, we look at the uses and side effects of Alizin for dogs. We look at how this injection is administered and stipulate that it should only be used under veterinary guidance.

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  1. What is Alizin for dogs?
  2. Uses of Alizin for dogs
  3. Alizin dosage for dogs
  4. How to administer Alizin for dogs
  5. How long does Alizin for dogs take to work?
  6. Alizin for dogs cost
  7. Side effects of Alizin for dogs
  8. Contraindications of Alizin for dogs

What is Alizin for dogs?

Alizin is the trade name for a medicine composed of the active ingredient known as aglepristone. This is a synthetic corticosteroid that counteracts the effect of the hormone progesterone, known as the progestation hormone. Progesterone is a hormonal steroid responsible for creating a favorable environment in the uterus to maintain a normal pregnancy. It prepares the endometrium (the epithelial uterine layer) to be receptive to the embryo and fetus.

In addition to preparing the dog's endometrium, progesterone allows the closure of the cervix and regulates the motor activity of the uterine muscles. It also regulates any immune reactions which might work against the development of a fetus.

Aglepristone blocks progesterone receptors by having three times greater affinity for them than progesterone itself. As a result, progesterone cannot exert its action. This inhibits the endometrial changes necessary for the maintenance of pregnancy and causes an abortion of the dog's pregnancy.

Alizin for Dogs - Uses and Side Effects - What is Alizin for dogs?

Uses of Alizin for dogs

While it is possible that aglepristone for dogs might have further uses in veterinary medicine, its sole current use is as an abortifacient. This means Alizin is used to terminate the pregnancy of a dog and disallow the development of their fetuses. It is only to be used during the the first 45 days of pregnancy, i.e. up to 45 days post-copulation.

The reasons why a dog may require an abortion will depend on various factors. These are either related to the well-being of the dog, the potential puppies and/or the guardian. A dog may require an abortifacient such as Alizin for the following reasons:

  • Unwanted pregnancy: a female dog may have been mated with a male unintentionally. The resultant pregnancy may be unsuitable for the guardians for a variety of reasons.

  • Health of the mother: pregnancy in some dogs may present health complications which can seriously harm certain dogs or even threaten their life. These include reproductive disorders, endocrine disorders and even advanced age.

  • Health of the puppies: there are certain conditions which might predispose the fetuses to harm. These include infections or parasitosis by which the mother is affected. A high potential for genetic defects is also an important consideration.

  • Inability to care for the puppies: financial, emotional or practical constraints may mean the puppies cannot be cared for appropriately.

Alizin is not an over-the-counter mediation. It is a prescription-only drug and must be prescribed by a veterinarian. If your dog is pregnant and any of the above issues mean abortion in dogs might be required, speak to your veterinarian about your options.

Learn more with our article on how to terminate a dog pregnancy.

Alizin dosage for dogs

The Alizin canine abortion shot it administered to pregnant dogs subcutaneously. The recommended dose is 10 mg of aglepristone per kilogram of body weight of the pregnant dog. This is equivalent to administering 0.33 ml of the veterinary product for every kilogram of the dog's weight. This dose is given in two injections 12 hours apart, meaning one dose is given every 12 hours for a total period of 24 hours.

Taking the above into account, the dosage of Alizin for pregnant dogs is as follows:

  • 3 kg pregnant dog: 1 ml of medication.
  • 6 kg pregnant dog: 2 ml of medication.
  • 9 kg pregnant dog: 3 ml of medication.
  • 12 kg pregnant dog: 4 ml of medication.
  • 24 kg pregnant dog: 8 ml of medication.
  • 30 kg pregnant dog: 10 ml of medication.
  • 42 kg pregnant dog: 14 ml of medication.

Giving a shot under the dog's skin can be difficult for some guardians. Alizin is often first administered in a clinical setting, but you may need to administer the second dose at home. Although Alizin is not a dog abortion pill, there are tablets which contains medications such as cabergoline for this purpose.

How to administer Alizin for dogs

Alizin is administered subcutaneously to pregnant dogs, preferably into the skin of the neck. It is recommended to perform a small massage at the application site. No more than 5 ml of the product should be administered at the same point, so in the case of large dogs, the applications should be divided into several different points around the same area.

For administration, a syringe with a dry, sterile needle should be used. As the product does not contain preservatives with antimicrobial action, it is important to disinfect the cap before removing the dose.

Learn about other veterinary medications which are administered via injection with our article on tylosin injections for dogs.

How long does Alizin for dogs take to work?

Once the dose of the drug is administered, abortion or embryonic resorption is expected to occur within seven days. If the medication is used after mating, it should be administered once the female's estrus has ended. This is the phase of heat during which she is fertile. Any further mating should be avoided until this period ends. This reduces the chances of inadequate treatment effectiveness.

In late-pregnant dogs, a partial abortion rate of up to 5% has been recorded. It is ideal to perform an ultrasound to confirm that the uterine contents have been completely evacuated. This test should be performed 10 days after treatment or 30 days after breeding. This will depend on how advanced the pregnancy was at the time the dog was treated.

An end to dog pregnancy doesn't only occur through abortion. Learn more with our article on why a dog has a miscarriage.

Alizin for dogs cost

The price of this veterinary medicine for canine species depends widely on location. Different markets have different pricing. In Europe, Alizin can range between €70 and €100 on average. The most common brand in Europe is Virbac Alizin for dogs. In the USA, it is a 10 ml dosage of Alizin will be a minimum of $100.

Alizin medication for dogs can be purchased at various veterinary pharmacies, specialized veterinary clinics, pet supply stores or authorized distributors of veterinary products. It is important to verify the availability of the medicine in recognized and authorized establishments to guarantee its quality and effectiveness.

In most countries, it is mandatory to have a veterinary prescription to purchase this type of medication. The prescription is issued by a veterinarian after evaluating the specific needs of each case. Only they can determine the appropriate dose and the most appropriate treatment for the pregnant dog. You should always consult a veterinarian before purchasing and administering Alizin to a pregnant dog.

Side effects of Alizin for dogs

As with any medication, the use of Alizin may cause unwanted side effects or adverse reactions. Common side effects that may occur in one in 10 treated dogs include:

  • Pain and inflammation at the injection points
  • Edema at the point of inoculation
  • Increase in the size of regional lymph nodes
  • Loss of appetite
  • Excitement
  • Diarrhea
  • Depression

In addition, there are other less common side effects, such as increased counts of total neutrophils, platelets, lymphocytes, hematocrit, urea and creatinine. Levels of chloride, potassium, sodium, alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase may also be raised. The possibility of infection in the uterus, vomiting and return to heat has also been reported. It is important to note that in very rare cases, hypersensitivity reactions or an ulcer at the injection site may occur.

Discover the effects of high creatinine levels in dogs with our related article.

Alizin for Dogs - Uses and Side Effects - Side effects of Alizin for dogs

Contraindications of Alizin for dogs

In the same way as any other medication, Alizin for dogs has a series of contraindications for use. They include dogs with:

  • Pregnancy over 45 days duration
  • Known hypersensitivity to aglepristone or any of the excipients of the medication
  • Liver or kidney disease
  • Diabetes mellitus
  • Addison's disease or hypoadrenocorticism
  • Being treated with drugs such as erythromycin, ketoconazole or itraconazole
  • Using corticosteroids (aglepristrone has antiglucocorticoid activity)
  • Bacterial endocarditis or chronic obstructive airway disease
  • Uterine infection (it increases mortality rate)

In addition to contraindications for the dog, it should not be handled by pregnant women or those who may be pregnant. Alizin is a drug that only a veterinarian should administer after evaluating the individual needs of the dog. To avoid an unwanted pregnancy, it is best to neuter the dog when the veterinarian deems appropriate.

Learn more about the benefits of neutering a dog by reading our article on whether neutered dogs live longer.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Alizin for Dogs - Uses and Side Effects, we recommend you visit our Medicine category.

  • Spanish Agency for Medicines and Health Products. Technical sheet of Alizin 30 mg/ml solution for injection for dogs. Retrieved from:
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Alizin for Dogs - Uses and Side Effects