Mibolerone (Cheque Drops)
Veterinary & Aquatic Services Department, Drs. Foster & Smith

Generic Name

Brand Name
Cheque Drops

Type of Drug
Androgenic steroid

Form and Storage
Store at room temperature unless otherwise specified by the manufacturer.

Indication for Use
Prevention of estrus, infertility, false pregnancy

General Information
FDA approved for use in dogs for estrus suppression. Mibolerone is an androgenic steroid which opposes the effects of estrogen and other hormones which cause ovulation and subsequent production of progesterone. Need to start the medication at least 30 days before proestrus to prevent the female from coming into heat. It is about 90% effective. Do not use in dogs which are to be bred in the future, as start of the next cycle may vary from 7-200 days from discontinuation of Cheque Drops. It has been used to lengthen short cycles which cause infertility and to treat false pregnancies. The false pregnancy may recur when the medication is discontinued. Because of this and the fact that most false pregnancies resolve on their own, no treatment is usually given. The most effective way to prevent these problems in dogs who are not showing in the breed ring and are not going to be used for breeding is by an ovariohysterectomy (spay).

Usual Dose and Administration
Contact your veterinarian.

Side Effects
May see increase in clitoral size which may resolve after treatment is discontinued, vaginal discharge, mounting other dogs, aggression, change in voice, increase in oily skin and body odor, reproductive tract lesions, tearing, or urinary incontinence. May also cause liver disease or death especially in cats.

Do not use in Bedlington Terriers or other breeds predisposed to kidney or liver disease.

Do not use in patients with liver or kidney disease.

Do not use in patients with androgen-dependent cancers such as perianal adenocarcinomas (malignant tumors that occur near the anus).

Do not use before the first estrus cycle, in pregnant or nursing dogs, or for more than 24 months.

Do not use in cats, as it has a very narrow therapeutic range.

Drug or Food Interactions
Do not use with progestins or estrogens.

May decrease effect of phenytoin.

No known food interactions.

May see increased tearing, lethargy, lack of appetite, weight loss, muscle pain, or liver, pancreatic, or thyroid disease. May cause death.



Mibolerone is used to prevent dogs from coming into heat, and in the treatment of some causes of infertility and false pregnancy. Do NOT use in cats. Do NOT use in dogs with or predisposed to liver or kidney disease. Contact your veterinarian if your dog experiences aggression, urinary incontinence, lethargy, lack of appetite, weight loss, vomiting, or yellow gums while taking mibolerone.

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Keep this and all other medications out of the reach of children and pets.

If you think your pet has been poisoned...

Contact your veterinarian or one of the Animal Poison Hotlines (listed below) if you think your pet may have accidentally received or been given an overdose of the medication.

**ASPCA Animal Poison Control Center - 24-hour service available throughout North America.

1-888-4ANI-HELP (1-888-426-4435). $65.00 per case, billed to caller's credit card.

Follow-up calls can be made for no additional charge by dialing 888-299-2973.

There is no charge when the call involves a product covered by the Animal Product Safety Service.

**Pet Poison Helpline - 24-hour service available throughout North America for pet owners and veterinary professionals who require assistance with treating a potentially poisoned pet.

1-800-213-6680 ($59.00 per incident). Staffed 24-hours a day.

Updated 6/20/17

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Reprinted from PetEducation.com.