lomustine
Pharmacologic class: Alkylating drug (nitrosourea)
Therapeutic class: Antineoplastic
Pregnancy risk category D
FDA Box Warning
• Give under supervision of physician experienced in cancer chemotherapy, in facility with adequate diagnostic and treatment resources. Most common and severe toxic effect is bone marrow suppression, which may contribute to bleeding and overwhelming infections in already compromised patients. Delayed bone marrow suppression is major toxicity, so monitor blood counts weekly for at least 6 weeks after dose. At recommended dosage, don't give courses more often than every 6 weeks. Bone marrow toxicity is cumulative; consider adjusting dosage based on nadir blood counts from previous dose.
Action
Inactivates neoplastic cells by alkylating DNA, causing DNA structural modification and fragmentation. Thought to act in late G1 or early S phase of cell cycle.
Availability
Capsules: 10 mg, 40 mg, 100 mg
Dose pack: two 10-mg capsules, two 40-mg capsules, and 100-mg capsules
Indications and dosages
➣ Adjunctive therapy in primary and metastatic brain tumors; secondary therapy in Hodgkin's disease
Adults and children: As monotherapy, 130 mg/m2 P.O. as a single dose q 6 weeks in previously untreated patients. In bone marrow suppression, initial dosage is 100 mg/m2 P.O. q 6 weeks; don't repeat dose until platelet count exceeds 100,000/mm3 and white blood cell (WBC) count exceeds 4,000/mm3. When given with other myelosuppressive drugs, adjust dosage accordingly.
Dosage adjustment
• Bone marrow depression (based on WBC and platelet counts)
Contraindications
• Hypersensitivity to drug
Precautions
Use cautiously in:
• renal or hepatic dysfunction, bone marrow depression
• pregnant or breastfeeding patients.
Administration
• Obtain CBC with white cell differential before starting therapy.
• Administer antiemetic before giving drug, as prescribed, to minimize nausea.
• Give 2 to 4 hours after meals to enhance absorption.
• If vomiting occurs shortly after administration, notify prescriber.
Adverse reactions
CNS: anxiety, confusion, dizziness, hallucinations, lethargy, headache, paresthesia, light-headedness, drowsiness, fatigue, seizures
GI: nausea; vomiting; anorexia; sore mouth, lips, and throat; GI bleeding
GU: amenorrhea, azoospermia, progressive azotemia, nephrotoxicity, renal failure
Hematologic: anemia, leukopenia, thrombocytopenia, bone marrow depression
Hepatic: hepatotoxicity
Skin: alopecia
Other: secondary cancers
Interactions
Drug-drug. Anticoagulants, non-steroidal anti-inflammatory drugs: increased bleeding risk
Myelosuppressants: increased bone marrow depression
Drug-diagnostic tests. Hemoglobin, platelets, red blood cells, WBCs: decreased values
Liver function tests, nitrogenous compounds: increased values
Patient monitoring
☞ Watch for evidence of overdose, including bone marrow depression, nausea, and vomiting.
☞ Monitor CBC and platelet counts closely. Watch for signs and symptoms of bleeding and bruising.
• Avoid I.M. injections if platelet count is below 100,000/mm3.
• Check kidney, liver, and pulmonary function tests frequently.
• Assess neurologic status carefully. Institute safety measures as needed to prevent injury.
☞ Watch for signs and symptoms of secondary cancers.
Patient teaching
• Instruct patient to contact prescriber if he vomits shortly after taking drug.
☞ Tell patient to immediately report easy bruising or bleeding, which may signal low platelet count.
• Advise patient to report changes in urination pattern.
• Instruct patient to avoid exposure to people with infections, because drug may make him more susceptible to infection.
☞ Caution female of childbearing age to use reliable contraception and to immediately report suspected or confirmed pregnancy.
• Advise female patient to inform prescriber if she is breastfeeding.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• Advise patient to minimize GI side effects by eating small, frequent servings of healthy food.
• Inform patient that drug may cause hair loss.
• Tell patient he'll undergo frequent blood testing during therapy.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.