Flashcards in Chemotherapy Deck (13)
How is chemotherapy administered and why?
For systemic delivery/absorption
Name six types of cytotoxic agents
- alkylating agents (act on DNA synthesis)
- antimetabolites (act on DNA itself)
- mitotic inhibitors
- intercalating agents (act on DNA transcription/duplication)
- spindle poisons (act on mitosis)
How do alkylating agents work?
- alkyl groups allow covalent bonds with other molecules
- DNA helix cross-links intra/interstrand
- attaches free guanines on separated DNA strands
- alkyl/methyl groups added to guanines where they don't belong
- inhibits correct orientation in base pairing
- causes DNA damage/mutation
- prevents DNA replication
What are the resistance mechanisms of alkylating agents?
- increased/decreased agent exit/entry
- inactivation of agent inside the cell
- enhanced repair of DNA lesions
How o antimetabolites work?
- similar structure to substances required by cell prior to division
- induce cell death in S phase when incorporated into nuclear material
- bind to vital enzymes to inhibit cell division
How so vinka alkaloids work?
- stops metaphase
- binds to tubuli
- blocks microtubule/spindle formation
How do taxanes work?
- stabilise microtubule bonds to prevent them changing in size during mitosis
Name two types of antimitotic antibiotics
Give examples of the effects antimitotic antibiotics can have?
- inhibit DNA/RNA synthesis
- increases membrane permeability to ions
- free radicals disrupt DNA chain and prevent mitosis
What is the overall effect of antimitotic antibiotic action?
stops DNA replication, causing part of it to cleave off causing cel death
What are the main principles of combination therapy?
Combine those with;
- different mechanisms (synergistic/additive/decreased risk of resistance)
- dissimilar toxicity (each administered to maximum tolerated dose)
Give some side-effects of chemotherapy
- pulmonary fibrosis
- renal failure