Alkyl sulfonates

Alkyl sulfonates

Busulfan, an alkyl sulfonate, has historically been used to treat chronic myelogenous leukemia, polycythemia vera (increased red blood cell mass and increased number of WBCs and platelets), and other myeloproliferative (pertaining to an overactive bone marrow) disorders. It’s also used for treatment of leukemia during bone marrow transplant procedures.

Warning!

Adverse reactions to nitrogen mustards

Many patients experience fatigue during nitrogen mustard therapy. Other adverse reactions include:

• severe leukopenia and thrombocytopenia
• nausea and vomiting
• stomatitis
• reversible hair loss
• severe skin reactions with direct contact
• severe tissue damage, if extravasation occurs.

Pharmacokinetics

Busulfan is rapidly well absorbed from the GI tract. Little is known about its distribution.

Metabolism and excretion

Busulfan is extensively metabolized in the liver before urinary excretion. Its half-life is 2 to 3 hours.

Pharmacodynamics

As an alkyl sulfonate, busulfan forms covalent bonds with the DNA molecules in alkylation.

Pharmacotherapeutics

Busulfan primarily affects granulocytes (a type of WBC) and, to a lesser degree, platelets. Because of its action on granulocytes, it has been used for treating chronic myelogenous leukemia and as adjunct therapy before and after bone marrow transplantation.

 

A backup option

Busulfan is also effective in treating polycythemia vera, although other drugs are usually used to treat it because busulfan can cause severe myelosuppression (halting of bone marrow function).

Drug interactions

There’s an increased risk of bleeding when busulfan is taken with anticoagulants or aspirin. Concurrent use of busulfan and thioguanine may cause liver toxicity, esophageal varices (enlarged, swollen veins in the esophagus), or portal hypertension (increased pressure in the portal vein of the liver). (See Adverse reactions to busulfan.)

Warning!

Adverse reactions to busulfan

The major adverse reaction to busulfan is bone marrow suppression, producing severe leukopenia, anemia, and thrombocytopenia (reduced white blood cells, red blood cells, and platelets, respectively). This reaction is usually dose-related and reversible.