Chemotherapy and immunosurpressants Flashcards
Name 4 mode of actions of chemotherapy drugs
- Antimetabolites
- Alkylating agents
- Intercalating agents
- Spindle poisions
How does 5- flurouracil (eg capecitabine) and methotrexate work?
Inhibit folic acid cycle, so inhibit purine synthesis (antimetabolite)
How do taxoids work?
Promote assembly and prevent disassembly of spindle–> cell death (spindle poisions)
How do platinum compounds such as cisplatin work?
Cause inter and intra strand adducts, leads to single, then double strand breaks which trigger apoptosis (alkylating agent)
How do vinca alkaloids work?
inhibit spindle formation
Name 3 classes of anti- emesis drugs
- Antihistamines (cyclizine)
- Anti muscarinics (hyoscine)
- Serotonin inhibitors (ondansetron)
- Dopamine antagonists (domperidone)
Name 1 vinca alkaloid?
Vincristine or vinblatine
Name 1 taxoid/ taxanes chemo?
paclitaxel
How do methotrexate and 6- mercaptopurine work?
They’re both antimetabolites- inhibit folic acid, so DNA synthesis
Why is chemo given in many rounds?
Fractional kill hypothesis- chemo will destroy tumours cells and bone marrow cells, but bone marrow will regenerate faster. Therefor successive rounds of chem will destroy the cancerous cells, whilst only depleting bone marrow by little bits each time
Give 2 examples of cancers that are very sensitive to chemo?
lymphomas, germ cell tumours, Small cell lung cancer.
Breast, colorectal, bladder, ovary and cervix have mild- moderate sensitivity
Give 2 examples of cancers which are not very susceptible to chemo?
Prostate, renal cell, brain tumours, endometrial
Give 3 methods of resistance to chemotherapy
- decreased entry/ increased expulsion of agent
- inactivation of agent within the cell
- enhanced repair of DNA lesions produced by alkylating
How can chemo be administered?
- IV bolus, bag, continious pump, PICC or hickman line
- oral
- subcut
- into body cavity (bladder, pleura)
- intra lesional
- intrathecal
- topical
- IM (rare)
Give 3 common side effects of chemo and how each can be minimised
- Alopecia (can be prevented with scalp cooling, but v. uncomfortable)
- Nausia and vomiting (acute, delayed or anticipatory, anti- emesis meds like hyoscine can help prevent this)
- Mucositis (sore mouth, throat, bleeds, diarrhoea etc, hard to prevent)
- myalgia (muscle pain)
Give a consequence of incorrect administration of chemo
A local reaction of local tissue destruction. For this reason the chemo is always administered by specialist nurse.
State rarer effects of chemo on 4 body systems
- Heart- cardiotoxicity leading to myopathy or arrhythmias
- lungs- fibrosis esp with bleomycin or cyclophosphamide
- Repro- usually sterile
- Renal- renal failure often due to tumour lysis releasing urate which precipitates in tubules, this risk can be minimised by giving drugs to reduce urate levels before giving chemo
- Blood- decreased RBCs, WBCs and platelets
- GI perforation at site of cancer (Esp w/ lymphoma)
What investigations should be done before starting chemo?
- BMI
- Body surface area
- Liver function
- Renal function
- heart function
- FBC
- general well being