lomustin

Lomustin, also spelled lomustine, is a nitrosourea alkylating chemotherapy agent used to treat certain cancers. It is lipophilic and readily crosses the blood-brain barrier, allowing it to reach tumor cells within the central nervous system.

Medical uses: In human medicine, lomustine has been used to treat brain tumors such as anaplastic astrocytoma and glioblastoma multiforme, typically as part of multi-agent regimens or in relapsed disease. It has also been employed in the treatment of other cancers in select regimens, often when standard therapies are not suitable. In veterinary medicine, lomustine is widely used in dogs for brain tumors and for other cancers such as mast cell tumors and lymphoma, administered as an oral capsule.

Mechanism and pharmacology: Lomustine alkylates DNA and RNA after metabolic activation, forming cross-links that impede replication and transcription. Its lipophilicity facilitates distribution to tissues including the central nervous system. It is administered orally, with dosing determined by body surface area or weight and given in cycles depending on the protocol. Metabolism occurs in the liver with renal and biliary excretion of metabolites.

Adverse effects: The principal toxicity is bone marrow suppression, leading to decreases in white blood cells and platelets. Other potential adverse effects include liver dysfunction, gastrointestinal symptoms, lethargy, and loss of appetite. Monitoring of blood counts and liver function is commonly recommended during therapy.

History: Lomustine was developed in the mid-20th century and marketed under brand names such as CeeNU; generic formulations are available. It remains in use in both human and veterinary oncology where appropriate.