Lomustine: An Overview

Summary

• ‍BRAND: Gleostine^® (formerly available as CeeNu^®)‍
• DRUG TYPE: Anti-cancer chemotherapy drug for humans, dogs or cats‍
• CONDITIONS TREATED: Lymphoma, melanoma, lung cancer and brain tumors‍
• ADMINISTRATION: Capsules on an empty stomach at bedtime‍
• CYCLES OF TREATMENT: Usually once every 3 to 8 weeks.‍
• LENGTH OF TREATMENT: Depends on animal’s condition and response

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Definition

What is Lomustine?

Lomustine is an alkylating agent that disrupts DNA replication, inhibits cell division, and hastens cell death.¹ The cytotoxicity of this drug is used to effectively kill rapidly dividing cells and is used to treat various types of cancer. Lomustine, also called CCNU or CeeNu^®, is rapidly absorbed from the gastrointestinal tract, metabolized in the liver, and excreted by the kidney.² Since it is lipid-soluble and easily moves across cell membranes, the drug readily crosses the blood-brain barrier to act within the central nervous system.¹

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Use & Administration

Lomustine use

Lomustine is commonly used chemotherapy drug in dogs in cats. It is often used for T cell lymphoma, cutaneous lymphoma, mast cell tumors, gastrointestinal lymphoma, histiocytic sarcoma, brain tumors, and many other cancers depending on the stage of disease, other therapies chosen, and owner preference.¹

Lomustine administration

• Lomustine comes in pill form and is commercially available. Sometimes this drug is compounded at special pharmacies when pets to not fit into the commercially available sizes.
• Depending on the type of cancer or condition being treated, it is usually taken as a single dose every 3 to 6 weeks which this variation depends on the pet's tolerability of the drug.⁵
• The amount prescribed for your pet depends on many factors, including patient’s size and weight, general health, or other treatments such as surgery, radiation, and additional chemotherapy drugs.

Your veterinarian will determine your pet’s dose and schedule. He or she will also conduct blood tests before and during treatment to monitor blood cell counts and screen for metabolites and enzymes reflecting liver and kidney function.²

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Precautions

Before using lomustine

Tell your veterinarian if any of the following are true:⁶

• Your pet is taking additional medications, including prescription, over-the counter, vitamins, or herbal remedies.
• Your pet is pregnant or will be pregnant.
• Your dog has pre-existing renal or liver disease.
• Your dog’s liver enzyme profile needs to be evaluated. Do not give your dog aspirin or aspirin-containing products without your veterinarian’s approval.
• Be sure that blood tests are conducted before and during treatment. These routine checks are used to assess your dog’s complete blood count (CBC) as well as liver and kidney function.
• These tests are also used to determine your pet’s response to lomustine therapy.⁶

Side effects & overdose

Possible side effects

The most common adverse effect of lomustine is bone-marrow suppression. This condition is often accompanied by low neutrophils, anemia, low white blood cell counts and low platelets [4]. In fact, approximately 40% of dogs will have a reduction in white blood cell counts (< 1,000 neutrophil cells/L), seven days after starting lomustine.¹ This reduction in immune function increases the risk for infection. Be on alert for signs of fever, shivering, and weakness which may indicate that your pet has developed an infection.

The symptoms listed below do not suggest that you take emergency measures immediately; however, if you notice that any of these symptoms persist for more than 24 hours, contact your veterinarian:²

• Vomiting
• Loss of appetite
• Diarrhea
• Sores in the mouth and throat
• Unusual tiredness or weakness
• Pale skin
• Fainting
• Hair loss
• Unsteady walk

More severe reactions are also possible. Contact your veterinarian immediately if your pet experiences any of the following symptoms:⁷

• Difficulty in breathing
• Shortness of breath
• Dry cough
• Chest pain
• Wheezing
• Decreased urination
• Swelling of face, feet, ankles, or lower legs
• Yellowing or eyes and skin
• Confusion
• Sudden change or loss of vision

Symptoms of overdose⁷

• Black, tarry stools
• Red urine (contains blood)
• Unusual bruising or bleeding
• Unusual tiredness or weakness
• Sore throat, cough, fever, or other signs of infection
• Shortness of breath
• Prolonged diarrhea
• Vomit containing blood or brown substance that look like coffee grounds
• Sores in the mouth and throat

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Interactions

Consult with your veterinarian regarding any drugs or supplements your pet may be taking prior to treatment with lomustine.

Some products that may interact with this drug include:⁴

• Nalidixic acid
• Azathioprine
• Cyclophosphamide
• Amphotericin B
• Chloramphenicol

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Care Tips At Home

• Make sure your pet is well hydrated and eating normally.
• Your pet may be at risk of infection, so report fever or any other signs of infection to your veterinarian immediately.
• Avoid commonareas with lots of other pets like dog parks and daycares where the health and vaccine status of other pets is unknown until your veterinarian tells you thecell counts are adequate for these activities.
• To reduce nausea, ask your veterinarian about anti-nausea medications.

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Read about other anti-cancer medications here.