Clinical Pharmacology of Anti-Cancer Agents Flashcards
Chemotherapy Agents classes (8)
- Alkylating agents
- Enzyme inhibitors
- Anti-metabolites
- Anti-microtubules
- Endocrine therapies
- Targeted therapies
- Immunotherapies
- Miscellaneous
Chemotherapy agents killing (2)
- preferentially kill proliferating cells
- non-specific agents kill both normal & malignant cells
Chemotherapy agents classification based on cell-cycle (2)
- Cell-cycle phase specific
- Cell-cycle non-phase specific
eg ifosfamide
Cell-cycle phase specific (3)
- toxicity to the proportion of cells in part of the cell cycle in which the agent is active in
- toxicity is the greatest during the S phase of DNA synthesis
- administrations as continuous infusion allows exposure to more cells in the specific cycle
Cell-cycle non-phase specific (2)
- exert their cytotoxic effect throughout the cell cycle, including resting phase
- cell killing is proportional to dose
eg alkylating agents
Alkylating agents types (2)
- Nitrogen mustards
- cyclophosphamide
- ifosfamide - Platinum analogues
- carboplastin
- cisplatin
- oxaliplatin
Alkylating agents MOA
- formation of positively charged carbonium ion
- binds to neutrophilic sites on biological molecules eg DNA
- cytotoxic effects :
1. Inhibition of DNA replication & transcription
2. Mispairing of DNA
3. Strand breakage - no cross-resistance
Cyclophosphamide ADR (5)
- Myelosuppression
- Cardiac dysfunction
- high dose - Ematogenic potential / CINV
- dose related - Haemorrhagic cystitis
- due to active metabolite acrolein
- high dose
- long term - SIADH
Cyclophosphamide (2)
- prodrug
- metabolised to active metabolites (acrolein & phosphoramide mustard)
Ifosfamide
- prodrug
- metabolised to isophosphoramide mustard, acrolein & chloroacetaldehyde
- cell cycle specific but phase non-specific
- MUST administer with mesna
Administration of Ifosfamide (3)
- administer with mesna (radical scavenger) to reduce the risk of haemorrhagic cystitis
- vigorous hydration with 1.5-2L of normal saline pre & post hydration
- increase oral fluid intake
Ifosfamide ADR (5)
- N/V
- CNS toxicity
- Nephrotoxicity
- Neurotoxicity
- due to accumulation of chloroacetaldehyde
- 2-5 days onset - Haemorrhagic cystitis (dose related)
- use mesna for prevention
- vigorous hydration w NS pre & post
- increase oral fluid intake
Neurotoxicity clinical presentation (3)
- Hallucinations
- Confusion
- Somnolence
2-5 days after initiation of Ifosfamide due to accumulation of chloroacetaldehyde
Antidote for neurotoxicity from Ifosfamide
Methylene blue
Platinum analogues examples (3)
- Cisplatin
- Carboplatin
- Oxaliplatin
Platinum analogues ADR
- Cisplatin (2)
- Carboplatin (1)
- Oxaliplatin (1)
Cisplatin :
- CINV
- dose limiting
- acute & delayed - Nephrotoxicity
- most
Carboplatin : Myelosuppression
- esp thrombocytopenia
Oxaliplatin : Peripheral neuropathy
Topoisomerase l inhibitor act on __
Single strand DNA
Topoisomerase ll inhibitor act on __
Double stranded DNA
Topoisomerase purpose as a normal cell function
- relieve the tension created by unwinding the DNA
Topoisomerase l example (1)
Irinotecan
- cell cycle phase specific
Topoisomerase ll examples (2)
- Etopiside
2. Doxorubicin (Anthracyclines)
MOA of topoisomerase l & ll inhibitors
- cause single/double DNA stand breaks
- prevent religation of DNA strand resulting in DNA breakage & cell death
Irinotecan ADR (2)
- topo l inihibitor
- Diarrhoea
- dose limiting
- manifest early & late
- treated with high dose loperamide (1st dose 4mg, subsequent doses 2mg q2h until diarrhoea free for 12h) - Cholinergic syndrome (SSLUD)
- pre-medicate w SC Atropine - UGT1A1 deficiency
- reduce starting dose
Cholinergic syndrome (5)
SSLUD
- Salivation
- Sweating
- Lacrimation
- Urination
- Diarrhoea
Etoposide ADR (1)
- topo ll inhibitor
Myelosuppression
- dose limiting
Anthracyclines example (1)
Doxorubicin
MOA of Anthracyclines (3)
- Induce formation of covalent topoisomerase ll - DNA complexes
- inhibition prevents the religation of DNA
- leading to DNA strand breaks - Intercalations between base pairs causing DNA breaks
- Metabolised in the liver to form oxygen free radicals
- additional cytotoxicity
Anthracyclines (Doxorubicin) ADR (3)
- Myelosuppression
- dose limiting - Cardiotoxicity
- Urine discoloration (red)