Cladribine is commonly used to treat hairly cell leukemia and multiple sclerosis. It is also used to treat histiocytosis.

Some of the off label uses of Cladribine include being towards immunosuppressive therapeutic approach in multiple sclerosis.

Caution should be exercised if Leustatin Injection is administered before, after, or in conjunction with other drugs known to cause immunosuppression or myelosuppression. These injections should be given under medical supervision of a qualified physician experienced in the use of antineoplastic therapy. Suppression of bone marrow function should be anticipated. This is usually reversible and appears to be dose dependent. Serious neurological toxicity (including irreversible paraparesis and quadraparesis) has been reported in patients who received Leustatin Injection by continuous infusion at high doses (4 to 9 times the recommended dose for Hairy Cell Leukemia). Neurologic toxicity appears to demonstrate a dose relationship; however, severe neurological toxicity has been reported rarely following treatment with standard cladribine dosing regimens.

Acute nephrotoxicity has been observed with high doses of LEUSTATIN (4 to 9 times the recommended dose for Hairy Cell Leukemia), especially when given concomitantly with other nephrotoxic agents/therapies.