Mitotane
Also known as: Lysodren
- **Give with Food:** Always administer this medication immediately after a meal (preferably one containing some fat or oil) to ensure proper absorption. - **Watch for Side Effects:** The goal of this drug is to reduce cortisol levels, but it can sometimes reduce them too much. Watch your pet closely for signs of an "Addisonian crisis," which include **lethargy, weakness, vomiting, diarrhea, or a sudden loss of appetite**. - **Stop if Sick:** If your pet stops eating or shows any of the above signs, **stop giving the medication immediately** and contact your veterinarian. You may be instructed to give a rescue dose of a steroid (like prednisone). - **Safety Precautions:** Mitotane is a potent cytotoxic drug. Wear gloves when handling the tablets, or wash your hands thoroughly afterward. Keep the medication strictly out of reach of children and other pets. - **Stress:** Your pet may need extra steroid medication during times of stress, such as surgery, boarding, or acute illness. Discuss this with your vet.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- Hyperadrenocorticism
- Medical treatment of hyperadrenocorticism
- Pituitary-dependent hyperadrenocorticism (Induction - Protocol A)
- Pituitary-dependent hyperadrenocorticism (Maintenance - Protocol A)
- Pituitary-dependent hyperadrenocorticism (Induction - Protocol B)
- Pituitary-dependent hyperadrenocorticism (Maintenance - Protocol B)
- Pituitary-dependent hyperadrenocorticism (Induction - Protocol C)
- Pituitary-dependent hyperadrenocorticism (Maintenance - Protocol C)
- Total adrenal ablation (Alternative Protocol D)
- Total adrenal ablation (Alternative Protocol E)
- Palliative medical treatment of adrenal carcinomas or adenomas
- Pituitary-dependent hyperadrenocorticism (Induction)
How it is given
Possible side effects
- Lethargy
- Ataxia
- Weakness
- Anorexia (loss of appetite)
- Vomiting
- Diarrhea
- Neurologic signs (uncommon)
- Liver changes (congestion, centrolobular atrophy, fatty degeneration)
- Iatrogenic hypoadrenocorticism (requiring long-term glucocorticoid/mineralocorticoid replacement in ~5% of dogs)
- Anorexia
- Diarrhoea
- Acute-onset neurological signs (2-3 weeks post-initiation)
- Iatrogenic hypoadrenocorticism
Cautions & contraindications
- Known hypersensitivity to mitotane
- Pregnancy (FDA Category C in humans; Class D in veterinary medicine - embryotoxic/teratogenic)
- Patients that are not eating well (should never be administered to anorexic animals)
- Not recommended in cats (trilostane is more effective and mitotane efficacy is highly variable)
- > **Warning:** Mitotane should never be administered to animals that are not eating well. * **Diabetes Mellitus:** Concurrent diabetes requires close monitoring as insulin requirements may rapidly decrease during initial treatment. * **Organ Dysfunction:** Dogs with preexisting renal or hepatic disease should receive the drug with extreme caution and intense monitoring. * **Stress Supplementation:** All dogs receiving mitotane therapy must receive additional glucocorticoid supplementation if undergoing physiological stress (e.g., surgery, trauma, acute illness). * **Human Safety:** Mitotane is a cytotoxic drug. Caregivers should avoid direct skin contact (wear gloves) and wash hands after administration.
Drug interactions
- CNS Depressants: Additive depressant effects may be seen if used concomitantly.
- Insulin: Diabetic dogs receiving insulin may have their insulin requirements rapidly decreased when mitotane therapy is instituted.
- Phenobarbital: Can induce enzymes and reduce the efficacy of mitotane; conversely, mitotane can induce hepatic microsomal enzymes and increase the metabolism of phenobarbital.
- Spironolactone: Has been demonstrated to block the action of mitotane in dogs; an alternate diuretic is recommended.
- Barbiturates: Increases the hepatic metabolism of mitotane
- Corticosteroids: Increases the hepatic metabolism of mitotane
Frequently asked questions
What is Mitotane used for in pets?
- **Give with Food:** Always administer this medication immediately after a meal (preferably one containing some fat or oil) to ensure proper absorption. - **Watch for Side Effects:** The goal of this drug is to reduce cortisol levels, but it can sometimes reduce them too much. Watch your pet closely for signs of an "Addisonian crisis," which include **lethargy, weakness, vomiting, diarrhea, or a sudden loss of appetite**. - **Stop if Sick:** If your pet stops eating or shows any of the above signs, **stop giving the medication immediately** and contact your veterinarian. You may be instructed to give a rescue dose of a steroid (like prednisone). - **Safety Precautions:** Mitotane is a potent cytotoxic drug. Wear gloves when handling the tablets, or wash your hands thoroughly afterward. Keep the medication strictly out of reach of children and other pets. - **Stress:** Your pet may need extra steroid medication during times of stress, such as surgery, boarding, or acute illness. Discuss this with your vet.
Is Mitotane safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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