Muliple meyaloma

my wife is being injected with cytoxan day 1, and cisplation day2.  What are these drugs, and what do they do. She was on thalomid last year and it seemed to be doing good, then she got shingles and was taken off thalomid, recieved radiation. which  

[Fernando Roque, MD]

Hi.  Both cisplatin and cytoxan are cytotoxic chemotherapy drugs.  Cytotoxic means that these drugs kill cancer cells (as opposed to some other types of cancer drugs which merely inhibit the growth and multiplication of cancer cells, but do not kill them). Cisplatin is a platinum containing compound which forms molecular "bridges" or "cross-links" among molecules found within the cancer cell's DNA (deoxyribonucleic acid).  DNA is the molecule which contains information required for the cancer cell to function and multiply.  Formation of cross-links deforms the cancer cell's DNA and prevents its proper functioning, which ultimately results in death of the cancer cell.  Cytoxan belongs to a different class of drugs (called alkylating agents), but has the same mechanism of action as cisplatin.