HOW CHEMOTHERAPY WORKS

By: Linda Chickering RPh

Clinical Director of Pharmacy

Reedsburg Area Medical Center

2000 N Dewey Ave

Reedsburg WI 53959

The mechanism of action of all standard chemo agents (i.e. 5FU, Xeloda, Doxorubicin, etc.) is the same, that they interfere in some way with DNA or RNA synthesis and inhibit the new growth of all fast growing cells (tumors, hair cells, gut/mucosal lining cells etc.). This is responsible for both their activity vs. tumors and their side effects. There are a variety of different ways in which they interfere with cell replication.

The only chemo agents with a different mechanism of action are the monoclonal antibody medications (those ending in -ab or -ib) which promote immune system attack on cells bearing certain markers. The hope with these medications is to have the body's own immune system attack just the tumor cells and leave the healthy cells alone. These agents tend to have typical immunological-agent side effects (such as allergic reactions and malaise).

The third class of agents on the Chemotherapy List are not chemo agents per se, but they are being used to modify the body's own chemistry in hopes of making a less hospitable environment for cancers that may grow better in a hormone-rich environment. These meds include the hormone modulators (tamoxifen, femara, etc. as well as celecoxib which is actually an anti-inflammatory agent). These agents do not have the typical chemotherapy side effects such as hair loss, nausea, vomiting, or mucositis.