General Description: Mitotane stops the growth of cells in the adrenal gland. It is used in treatment of Cushing’s disease in dogs and also to treat some types of cancer affecting the adrenal gland. Pregnant women, or those wishing to conceive should not handle this drug. It is available in 500 mg scored tablets.

What is this drug?

An adrenocortical cytotoxicant
Given by mouth
Reasons for prescribing:

For the treatment of hyperadrenocorticism (Cushing’s disease) in dogs
For treatment of some types of cancer affecting the adrenal cortex
What dogs/cats should not take this medication?

Use with caution in pets with diabetes, liver or kidney disease
Pregnant or nursing dogs
If your pet has had an allergic reaction to mitotane or like products before

Read and follow the label carefully.

Wear gloves when handling this medication. Wash hands well after handling this drug.

Give the exact amount prescribed and only as often as directed. Give mitotane with a fatty or oily meal (to increase absorption). Mitotane powders and liquids sprinkled on food with a little corn oil is an effective way to give the drug. But if your dog has been well-managed on whole tablets, switching to a liquid or powder, or giving a crushed tablet, could dramatically increase the amount of active ingredient that enters the bloodstream. Do not switch forms unless under close supervision by your veterinarian.

Your pet will receive high doses for the first 1-2 weeks, and then the dose will be lowered under the direction of your veterinarian.

Mitotane decreases the body’s ability to handle stress. Glucocorticoids (ex. prednisone) may be prescribed for use during stressful situations (ex. travel, surgery, house guests, new baby, etc.).

Expect to see the signs of hyperadrenocorticism (lethargy, increased drinking, eating, or urination) improve within the first 2 weeks of treatment. Skin and hair loss changes may take several months to improve.

What if a dose is missed?

If a dose is missed, give it as soon as you can. If it is time already for the next dose, skip the missed dose and go back to the normal schedule. Do not give two doses at the same time.

What to tell/ask veterinarian before giving medication?

Talk to your veterinarian about:

When will your pet need to be rechecked
What tests may need to be performed prior to and during treatment with this drug
What are the risks and benefits of using this drug
Tell your veterinarian about:

If your pet has experienced side-effects on other drugs/products
If your pet has experienced digestive upset now or ever
If your pet has experienced anemia, liver or kidney disease now or ever
If your pet has experienced diabetes or any other medical problems or allergies now or ever
All medicines and supplements that you are giving your pet or plan to give your pet, including those you can get without a prescription. Your veterinarian may want to check that all of your pet’s medicines can be given together.
If your pet is pregnant or nursing or if you plan to breed your pet
Storage and Warnings:

Store in a tight, light resistant childproof container at room temperature away from heat and direct sunlight.

Keep this and all medication out of reach of children and pets. Do not handle this product if you are pregnant or trying to conceive.

Wear gloves when handling this medication. Wash hands well after handling this drug. It can be very toxic. Do not allow mitotane to enter the environment through the soil or water. Return any leftover drug to your veterinarian for proper disposal.

Call your physician immediately if you accidentally take this product.

Potential side effects:

Most common effects: lethargy, weakness, loss of appetite, incoordination, depression, vomiting and diarrhea. Mitotane must be given in high doses until it starts to work. Most dogs will have an effect within 2-35 days, whereby the dose can be reduced from twice daily to twice a week. If your pet becomes unusually tired or weak, contact your veterinarian immediately.
Possible liver damage (loss of appetite, yellowing of gums, eyes or skin) especially in pets with a pre-existing liver condition
If you notice anything unusual, contact your veterinarian
Can this drug be given with other drugs?

Yes, but possible interactions may occur with barbiturates, CNS depressants (ex. acepromazine, amitriptyline), insulin, phenobarbital, phenytoin, prednisone, prednisolone, spironolactone, theophylline, and warfarin
If your pet experiences any unusual reactions when taking multiple medications, contact your veterinarian.

Contact your veterinarian immediately if pet receives more than the prescribed amount.

What else should I know?

Notify your veterinarian if your animal’s condition does not improve or worsens despite this treatment.

As with all prescribed medicines, mitotane should only be given to the pet for which it was prescribed. It should be given only for the condition for which it was prescribed.

This is just a summary of information about mitotane. If you have any questions or concerns about mitotane or the condition it was prescribed for, contact your veterinarian.


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