Thursday, 11 November 2010

MRCP revision battle 46.4: Cytotoxic Agents

A quick run-through of the main mechanisms of action and MRCP-relevant side-effects of some common cytotoxic agents.


Vincristine
  • Inhibits microtubule formation
  • Used in:
    • lyphoma
    • leukaemia
    • breast and lung cancer
  • Side effects
    • peripheral paraesthesia
    • loss of tendon reflexes
    • abdominal pain

Cisplatin
  • Cross-links DNA
  • Used in:
    • testicular, cervical, bladder, lung, head and neck cancers
  • Side effects
    • nephrotoxic
    • ototoxic
    • peripheral neuropathy
    • hypomagnesaemia
    • myelosupression


Bleomycin
  • Degrades DNA
  • Used in:
    • metastatic germ cell cancers
    • non-Hodgkins lymphoma
  • Side effects
    • increased pigmentation
    • pulmonary fibrosis


Doxorubicin
  • inhibits RNA/DNA synthesis
  • used in:
    • leukaemia
    • lyphoma
    • breast cancer
  • Side effects
    • red colouration of urine
    • SVT
    • cardiomyopathy

Methotrexate
  • inhibits dihydrofolate reductase
  • used in:
    • non-Hodkins lymphoma
    • choriocarcinoma
    • RA
  • Side effects
    • excreted by kidneys so should be avoided in renal disease
    • should be avoided in significant ascites/pleural effusion as may accumulate then suddenly return to circulation causing myelosupression
    • myelosupression
    • mucositis
    • pneumonitis


Cyclophosphamide
  • alkylating --> cross links DNA. Inactive until metabolised by liver
  • used in:
    • CLL
    • lymphoma
    • sarcoma
  • Side effects
    • haemorrhagic cystitis 


To continue the randomness of the 46th set of battles lets look at congential infections