Chapter 8: Immune system and malignant disease Flashcards
What do immunosuppressants do?
Suppresses or prevents the immune response
Immunosuppressant uses?
- transplant rejection
- inflammatory diseases e.g. rheumatoid arthritis, severe eczema or IBD
Antiproliferative immunosuppressants?
- azathiopurine
- mercaptopurine
- mycophenolate mofetil
Other immunosuppressants?
- ciclosporin
- tacrolimus
- corticosteroids
What should be avoided with immunosuppressants ?
Live vaccines! - high risk of infections when on immunosuppressants
Azathioprine/mercaptopurine MOA
Mercaptopurine inhibits purine metabolism therefore DNA, RNA and protein synthesis. Azathioprine is metabolised to mercaptopurine
Azathioprine/mercaptopurine side effects?
- hypersensitivity reactions; STOP immediately!; rash, fever, myalgia, arthralgia, malaise, interstitial nephritis, nausea, vomiting and diarrhoea
- bone marrow suppresion: pre-treatment screening for thiopurine methyl transferase. Low enzyme activity = high risk of myelosuppression
Azathioprine/mercaptopurine interactions?
- reduce dose with allopurinol = toxicity
- allopurinol is a xanthine oxidase inhibitor; inhibits metabolism of purines
Mycophenolate mofetil MOA?
Metabolised to mycophenolic acid. A selective mode of action than purine synthesis inhibitors e.g. azathioprine
“Mycophenolate mofetil (MMF, CellCept) is a prodrug of mycophenolic acid (MPA), an inhibitor of inosine-5’-monophosphate dehydrogenase. MPA depletes guanosine nucleotides preferentially in T and B lymphocytes and inhibits their proliferation, thereby suppressing cell-mediated immune responses and antibody formation.”
Mycophenolate mofetil side effects?
- hypogammaglobinaemia: recurrent infections = measure serum immunoglobulin
- bronchiectasis: respiratory symptoms e.g. cough, dyspnoea
- bone marrow suppression
Mycophenolate mofetil and pregnancy?
GENOTOXIC AND TERATOGENIC
- women: two methods of effective contraception until 6 weeks after discontinuing
- men: use condoms until 90 days after discontinuing OR female partners use effective contraception until 90 days after discontinuing
What is tacrolimus?
Calcineurin inhibitor
Tacrolimus side effects?
- heart = cardiomyopathy e.g. arrhythmias
- kidney = nephrotoxicity
- liver = hepatotoxicity
- bone marrow = blood dyscrasias
- blood = hypertension, hyperglycaemia, hyperuricaemia
- neurotoxicity = headaches and tremors
- eye disorders = blurred vision, photophobia
- skin = rashes, toxic epidermal necrolysis
Tacrolimus patient counselling?
- avoid exposure to sunlight/UV light: use wide spectrum SPF
- diet: avoid high potassium and grapefruit juice = high tacrolimus level
- driving may be affected
MHRA reminder to maintain on the same brand (oral), reports of toxicity and transplant rejection when switching between products
Ciclosporin MOA?
Lowers activity of T cells and their immune responses
Ciclosporin side effects?
- kidneys = nephrotoxicity
- liver = hepatotoxicity
- bone marrow = blood dyscrasias
- blood = lipids (hyperlipidaemia), hypertension, hyperkalaemia and hypOmagnesaemia
- visual disturbances = secondary to benign intracranial hypertension
- gingival hyperplasia
- neurotoxicity
Ciclosporin patient counselling?
- avoid excess sun exposure/UV light: use wide spectrum SPF
- diet: avoid high potassium and grapefruit jucie = high ciclosporin level
MHRA advice: oral ciclosporin, maintain on same brand - switching between can lead to clinically important changes in ciclosporin concentration
Cancer therapy aims?
Curative intent OR prolong life OR palliate symptoms
What is neoadjuvant cancer therapy?
- initial chemotherapy aimed at shrinking the primary tumour
- this makes local therapy less destructive or more effective
What is adjuvant cancer therapy?
- this follows a definitive treatment of the primary disease when there is a high risk of sub-clinical metastatic disease
What are the guidelines for handling cytotoxic drugs?
- trained personnel should reconstitute cytotoxic drugs
- designated pharmacy area for reconstituting cytotoxic drugs
- wear protective clothing and cover eyes
- first aid should be specified
- pregnant staff should avoid exposure to cytotoxic.
- females of child bearing age should be informed of reproductive hazard
- local procedures for spillages and safe waste disposal
- monitor staff exposure
Safe system requirements for cytotoxics?
Chemotherapy is given as a part of a wider pathway of coordinated care by a multidisciplinary team:
- cytotoxic medicines should be prescribed, dispensed and administered according to written protocol or treatment plan
- injectable cytotoxic drugs should only be dispensed if they are prepared for administration
- oral cytotoxic medicines should be dispensed with clear directions for use