Ovaban and Cheque use in Dogs


Cheque (Rx) vs Ovaban - side effects

Q: We have a black lab that is due to come into heat in October, during bird season. We have heard of a product called, Check. Probably spelled different. It is a liquid that you give a drop of each day. We are thinking about using this to delay her heat cycle. Can you tell us of any bad side affects? How early should you begin medication? Thanks!! Chuck

A: Chuck- The product you are referring to is Cheque (Rx). The generic name is mibolerone. Personally, I would be reluctant to use this medication, because it has too many side effects for me to be comfortable with it. It can cause clitoral enlargement, which may or may not be reversible. It is not recommended for use in a bitch intended for future breeding as it may cause problems with future fertility. Vaginal infections, increased body odor, abnormal behavior, urinary incontinence, riding behavior, oily skin and liver damage may also occur. The medication must be started at least 30 days prior to the time the next estrus would occur in order to be affective. If there is any chance the bitch is pregnant this medication must not be used as it can cause birth defects.

An alternative medication with less side effects, although not entirely free of problems, is megestrol acetate (Ovaban Rx). This is a pill. It can be given right at the start of the estrus to delay it a while or given in anticipation of estrus over a longer period of time.

Neither of these medications should be used in the first heat period.

Hope this helps. Mike Richards, DVM

Calculating Ovaban dosages:

Q: Dear Dr. Mike, I wrote to you yesterday about the use of Ovaban in preventing a heat cycle in a dog and I want to thank you for responding so quickly the information was very helpful. I have one more question if you don't mind. My vet gave me enough ovaban for 32 days at 3/4 a tablet everyday. I think each tablet is 5mg. My dog weighs 14lbs.. I was wondering if that was the low dose you were speaking of? Could I just give her 1/2 a tablet once and day and that be enough to stop a hear? Again, thank you for your time and consideration.

A: The dose for Ovaban is 0.55mg/kg/day for the 32 day dosing schedule. A 14 lb dog weighs 6.4 kg.

6.4kg x 0.55mg/kg/day = 3.52mg/day

You would need to give 3/4th of a tablet to ensure that it would work since 1/2 tablet would be about a 29% under dosage. I am not sure the medication would be reliable with this high of an under dosage. I know that the difference seems small when looking at the size of the pill, but it is pretty big when looking at the difference in actual dosage. Almost always, it is best to use the recommended dosage of medication for the recommended time. Mike Richards, DVM

Ovaban side effects

Q: I have been giving my mixed breed dog ovaban for several years. She is approximately 11 years old now. After her last heat she developed a kidney or urinary tract infection and responded to a treatment of amoxicillin. I would like to know if there is any connection between giving her ovaban and her infection. Thank you.

A: I do not know of a correlation between the use of Ovaban and urinary tract infections. It has been implicated for predisposing dogs to uterine infections in intact female dogs. The side effects that I am aware of for megestrol acetate (Ovaban Rx) in dogs are weight gain, changes in hair color, uterine infections, enlargement of the mammary glands (sometimes with milk production) and rarely mammary cancer. Weight gain is common but the other effects are less likely to occur in any individual dog.

Mike Richards, DVM

Postponing "heat" cycle in dogs:

Q: Dear Dr. Mike, I have a 11/2 year old female Jack Russell Terrier who is not spayed and I will be attending a school for training dogs and will be taking her with me. My problem is she is due to go into hear right in the middle of my schooling and this will cause problems I was told of a drug called ovaban hat can be given so the dog will not go into heat. Is this even possible or safe? Any advice you can give would be appreciated. She is in good health but I want her to stay that way.

A: Megestrol acetate (Ovaban Rx) is reasonably safe to use to delay estrus periods after the first one. It is either given at a low dose for 32 days in between heat periods to delay estrus or it is given in higher doses for 8 days and started at the very first signs of heat. For your situation, the first way to use it is probably better.

There is probably a slight increase in the frequency of pyometra (uterine infection) in dogs that have been treated with megestrol acetate. I don't think this is a major risk but it should be considered in the decision to use this medication. Mike Richards, DVM


Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...