Pyometra: Exploring Treatment Options Beyond Spay

When Pyometra Strikes: What Treatment Options Are Available?

If you’ve ever received that dreaded diagnosis of pyometra in one of your bitches, you know the feeling—worry for her health, questions about whether she’ll recover, and uncertainty about what this means for her breeding future. The good news? While surgery remains the most definitive treatment, there are also medical options available that may allow you to preserve her fertility, especially if the condition is caught early.

What is Pyometra? Pyometra is a life-threatening uterine infection that typically occurs during diestrus – the phase in the reproductive cycle following estrus (heat) when progesterone levels are high and the body is hormonally prepared to support a pregnancy. When progesterone levels are high, the cervix is often partially or completely closed, trapping infection inside. The uterus fills with pus, and if not promptly treated, the condition can lead to sepsis, organ failure, or death. For breeders, a pyometra diagnosis often feels devastating: not only is a beloved dog’s life at risk, but her reproductive future may be as well.

This post walks you through the most commonly used protocols for treating pyometra in breeding bitches, including their safety profiles, pros and cons, and when each might be considered.

Surgical Treatment: The Gold Standard for Critical Cases

Ovariohysterectomy (spay) is the go-to treatment for pyometra in most general practices. It removes the infection source entirely, prevents recurrence, and provides fast resolution in most cases. However, it also results in the irreversible loss of fertility and may pose greater anesthetic and surgical risks for systemically ill dogs. While it’s a life-saving option, it may not be ideal for valuable breeding animals if medical management is a viable alternative.

Alizin (Aglepristone): The Safest Medical Option

Alizin is a progesterone receptor blocker. It works by blocking progesterone receptors, which relaxes the cervix and allows the infected contents of the uterus to drain. It’s generally very well tolerated, with minimal side effects such as mild injection site swelling or transient anorexia. Alizin is especially effective in open-cervix cases and is usually paired with antibiotics for best results. Because it does not induce uterine contractions, it is considered safer for treating closed-cervix pyometra as well.

Despite its benefits, Alizin is not legally marketed in the United States and cannot be purchased from American pharmaceutical manufacturers. However, it can be imported by veterinarians with a special FDA permit, and availability is slowly improving as more reproductive practices navigate that process. We DO offer treatment with Alizin at Elon Oaks Veterinary Hospital—making medical management more accessible for breeders who wish to preserve fertility.

Prostaglandins (Cloprostenol or Lutalyse): Hormonal Muscle Movers

Prostaglandin medications mimic the natural hormone prostaglandin F2-alpha, which plays a key role in ending the diestrus (high progesterone) phase. These drugs help break down the corpus luteum (which produces progesterone) and stimulate uterine contractions to evacuate the infection. In simple terms, they lower progesterone levels and encourage the uterus to “clean itself out.”

Cloprostenol is a synthetic, more targeted version that tends to be better tolerated. Lutalyse (dinoprost) is the natural form, which is more widely available but often associated with stronger side effects like vomiting, panting, and diarrhea. Both require careful dosing and close monitoring. Depending on your veterinarian’s hospital protocols and what’s stocked in-house, either drug may be used. They can also be paired with cabergoline for enhanced hormone suppression. Because these drugs stimulate uterine contractions, there is an increased risk of using them in case of a closed pyometra (i.e. the cervix is completely closed). 

Cabergoline and Bromocriptine: Helping Hormones Let Go

These medications are dopamine agonists that reduce prolactin—a hormone that helps sustain progesterone production in the latter half of diestrus. By lowering prolactin, they help progesterone levels drop, assisting the uterus in returning to a non-receptive state. Put simply, they help the body “let go” of the hormonal conditions that support infection.

Cabergoline is usually preferred because it’s better tolerated and given once daily. Bromocriptine is more affordable, but can cause more gastrointestinal upset and must be given more frequently. Neither drug is effective on its own and therefore they are used in combination with prostaglandins to boost treatment efficacy.

Choosing the Right Protocol

Treatment must be tailored to the individual bitch. Critically ill, unstable, or closed-cervix cases are safest with immediate spay, as are any cases in which preservation of fertility isn’t a priority. For stable, open-cervix bitches whose owners wish to preserve fertility, Alizin is typically the best option if it’s available. If Alizin isn’t available, or it’s out of the budget, your reproductive veterinarian would be able to propose the best combination of prostaglandin +/- dopamine agonist for your individual patient. 

Important Note: If you choose medical management, it is essential to breed the bitch on her next cycle. Studies suggest recurrence rates of pyometra may be as high as 77% in medically treated dogs that are not bred on the next heat (Jitpean et al., 2017).

Conclusion

If you’re facing a pyometra diagnosis, take a deep breath. Early detection and collaboration with a reproductive vet can give you more options than you might expect. While medical management isn’t appropriate for every case, it’s increasingly successful in preserving fertility in carefully selected patients. As always, being proactive with health monitoring, progesterone testing, and timely treatment goes a long way.

References:

• Jitpean, S., Hagman, R., Ström Holst, B., Höglund, O.V., Pettersson, A., & Egenvall, A. (2017). Breed variations in the incidence of pyometra and mammary tumours in Swedish dogs. Reproduction in Domestic Animals, 52(Suppl 2), 74–78.

• Verstegen, J., Onclin, K., Silva, L.D.M. (1999). Comparisons of different combinations of analogues of PGF2α and dopamine agonists for the termination of pregnancy in dogs. Veterinary Record, 144(15), 416–419.

• Fieni, F., Dumon, C., Tainturier, D., & Siliart, B. (2001). Clinical use of aglepristone in bitches with pyometra. Theriogenology, 55(6), 1367–1378.