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Can A Dog's Heat Cycle Be Stopped With Medication?

| Updated August 11, 2017

Once your pup sexually matures, she'll begin going into estrus, commonly referred to as heat, twice a year. At this point, if she hasn't been spayed, she'll attract and seek out male pooches to mate with. Fortunately, there are medications available to stop her estrus cycle once it begins. These drugs have limitations, though, and aren't a permanent solution to ending her heat cycles.

Love Is in the Air

When your pooch reaches between six and 24 months of age, she'll begin her first heat cycle. The usual heat cycle lasts around 18 days and for half of this time she'll be open to mating with any canine suitors who are around after she ovulates, according to the American Society for the Prevention of Cruelty to Animals. Heat cycles typically occur every six months unless you spay your pup. During a spay procedure, your vet will remove your pup's reproductive organs, a procedure which permanently prevents her from going into estrus again. If you want to breed your pup, medications may work better for your situation.

Stopping Estrus to Prevent Unwanted Pregnancies

The United States Food and Drug Administration has approved two medications for use in dogs to stop the estrus cycle. Megestrol acetate is an oral medication that you give to your pooch when she starts showing signs of going into heat, such as behavioral changes, nervousness or mating behaviors around other dogs. After giving this medication to your dog for eight days, her heat cycle should stop and she'll go into heat again within six months. Mibolerone is a different medication that is also administered orally, but you must give it to your pooch 30 days before her heat cycle begins. It won't stop a heat cycle, but rather it prevents it from starting at all.

The Drawback of Drugs

When it comes to using medications to prevent or stop a heat cycle in your pup, you'll need to consult with your vet to see if they are appropriate for her. You can't use medications to prevent or stop your dog's first heat cycle, nor can you use them in dogs with kidney or liver problems. These products are hormone-based and can cause unwanted side effects, including behavioral changes, urinary incontinence and lethargy. A pooch can go back into heat when you stop her treatment with mibolerone within one week, so it's not an ideal solution. Giving too much of these drugs to your dog can be dangerous to her and even fatal in some cases.

Medications for Life?

Hormone-based drugs like mibolerone and megestrol acetate aren't 100 percent effective in stopping a heat cycle in your pooch and aren't meant as lifetime solutions to prevent pregnancy in canines. In fact, you can't administer mibolerone for more than 24 months to pups, according to PetEducation.com. When it comes to megestrol acetate, the Saint Louis Zoo website states that the drug shouldn't be used for more than two heat cycles. This drug can also worsen some mammary tumors in pups afflicted with them. The only permanent solution to preventing a pooch from going into heat is to have her spayed. Ideally, you should spay your dog prior to her first heat cycle, by six months of age.

By Susan Paretts


About the Author
Based in Las Vegas, Susan Paretts has been writing since 1998. She writes about many subjects including pets, crafts, television, shopping and going green. Her articles, short stories and reviews have appeared in "The Southern California Anthology" and on Epinions. Paretts holds a Master of Professional Writing from the University of Southern California.