ChlorambucilRx

Trade Names: Leukeran

Drug Class: Alkylating agent

Preparations: 2-mg tablet

Dose: 0.05–0.1 mg/kg/day; usual dose range, 4–6 mg/day, with dose adjusted according to WBC count

Indications: Immunosuppressant, occasionally used as an alternative for patients who cannot tolerate cyclophosphamide

Mechanism of Action: Alkylation and cross-linking of DNA strands interfering with DNA replication

Contraindications: Hypersensitivity, bone marrow suppression, BCG and live virus vaccines

Precautions: Teratogenic; can cause severe immunosuppression and cytopenias; carcinogenic; caution and dose reduction in hepatic and renal impairment

Monitoring: CBC, platelet count, serum uric acid, and LFTs frequently after initiation, then every 4 weeks

Pregnancy Risk: D

Adverse Effects
Common: Myelosuppression, rash, GI intolerance, oral ulceration
Less common: Confusion, seizures, sterility, pulmonary fibrosis, liver necrosis, drug fever, secondary malignancy, Stevens-Johnson syndrome, azoospermia, irreversible bone marrow failure

Drug Interactions
Immunosuppressants: Concurrent use of chlorambucil increases risk of myelosuppression and infection.

Patient Instructions: Avoid live virus vaccines. Avoid pregnancy. Regular monitoring is required.

Comments: When possible, azathioprine and methotrexate are used in preference to alkylating agents because the risk of secondary neoplasms is lower.  Decrease  in neutrophils and lymphocytes progresses even after drug is discontinued.

Clinical Pharmacology: Well absorbed; food decreases absorption 20%. Half- life 2 hours; hepatic metabolism and renal excretion of metabolites

Cost: $$$

BIBLIOGRAPHY

Steinberg AD. Chlorambucil in the treatment of patients with immune-mediated rheumatic diseases. Arthritis Rheum 1993;36:325–328.PMID:8452576