Blast crisis is diagnosed if any of the following are present in a patient with CML:
>20% blasts in the blood or bone marrow
The presence of an extramedullary proliferation of blasts

Treatment
The only curative treatment for CML is a bone marrow transplant or an allogeneic stem cell transplant. Other than this there are four major mainstays of treatment in CML: treatment with tyrosine kinase inhibitors, myelosuppressive or leukopheresis therapy (to counteract the leukocytosis during early treatment), splenectomy and interferon alfa-2b treatment. Due to the high median age of patients with CML it is relatively rare for CML to be seen in pregnant women, despite this, however, chronic myelogenous leukemia can be treated with relative safety at any time during pregnancy with the cytokine Interferon-alpha. Chronic phase
In the past, antimetabolites (e.g., cytarabine, hydroxyurea), alkylating agents, interferon alfa 2b, and steroids were used as treatments of CML in the chronic phase, but since the 2000s have been replaced by Bcr-Abl tyrosine-kinase inhibitors drugs that specifically target BCR-ABL, the constitutively activated tyrosine kinase fusion protein caused by the Philadelphia chromosome translocation. Despite the move to replacing cytotoxic antineoplastics (standard anticancer drugs) with tyrosine kinase inhibitors sometimes hydroxyurea is still used to counteract the high leukocyte counts encountered during treatment with tyrosine kinase inhibitors like imatinib; in these situations it may be the preferred myelosuppressive agent due to its relative lack of leukemogenic effects and hence the relative lack of potential for secondary haematologic malignancies to result from treatment.
See also
Bupropion/dextromethorphan
Deudextromethorphan/quinidine

References
External links
"Dextromethorphan hydrobromide mixture with quinidine sulfate". Drug Information Portal. U.S. National Library of Medicine.