Immunosuppressants Flashcards

1
Q

What are some of the conditions that are treated with immunosuppressants?

A

Bone marrow/organ transplants
Autoimmune conditions

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2
Q

What are the 5 types of immunosuppressants

A

Glucocorticoids
Immunophilin ligands
MMF
Cytotoxic agents eg. Methotrexate
Ig-based therapies

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3
Q

What are DMARDs

A

Disease Modifying Anti-Rheumatic Drugs: stop/slow the disease process of inflam. forms of arthritis and CT disorders

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4
Q

what are the DMARDs classifications

A

conventional: Metho, Hydroxychloroquine, Sulfasalazine: target entire immune system broadly

Biologic: target very specific steps in inflam. process

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5
Q

How do Glucocorticoids suppress the immune system?

A

steroid enters the cell, binds to cytosolic receptors, changes gene transcription within the cell (eg. make less interleukin) and mRNA is then edited to produce different proteins

Essentially:
1. Decrease synthesis of prostaglandins, leukotrienes, cytokines

  1. Inhibit prolif. of T-lymphs, cytotoxic to some T cells (impairs cell-mediated immunity)
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6
Q

Clinical uses of glucocorticoids

A

Suppress immunological reactions after organ transplantation

Treatment of haematological cancers

Autoimmune diseases (RA, UC)

Asthma/COPD: reduce inflam.

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7
Q

Adverse effects associated with longterm glucocorticoid use?

A

ADRENAL SUPPRESSION (inhibition of HPA axis-prolonged use of steroids (more than 2 weeks), abrupt withdrawal can lead to adrenal crisis)

Behavioural changes: Insomnia

Cushings, Cataracts

Diabetes

Muscle wasting

Osteoporosis

Psychosis

Stunting, Salt retention

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8
Q

What are three examples of immunophilin ligands?

A

Tacrolimus
Ciclosporin

these above two are calcineurin inhib

Sirolimus

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9
Q

Clinical uses of immunophilin ligands

A

Prevent rejection following solid organ transplant

Prevents Graft versus Host Disease in stem cell transplant

Autoimmune conditions

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10
Q

What are immunophilin ligands?

A

Immunophilins are small proteins found in cytoplasm of T cells
NB role in responses of t cells to activation and cytokine production

They work by binding to immunophilins to inhibit their activation of calcineurin

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11
Q

How does Ciclosporine WORK?

A

Binds to cyclophilin:i nhibits calcineurin activation and reduce entry of NFAT into the nucleus and reduce prod. of cytokines that normally occurs in response to T cell activation

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12
Q

How does Tacrolimus work?

A

Binds to FK-binding protein: inhibits calcineurin activation and reduce entry of NFAT into the nucleus and reduce prod. of cytokines that normally occurs in response to T cell activation

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13
Q

What does Sirolimus bind to?

A

FK-binding protein

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14
Q

Sirolimus MOA?

A

Essentially: interferes with prolif. of lymphs

Does not inhibit calcineurin but rather inhibits kinase activity of mTOR pathway which regulates growth and proliferation

inhibiting mTOR means that sirolimus effectively inhibits T cell proliferation in response to IL-2

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15
Q

What are the respective formulations for the three immunophilin ligands

A
  1. Ciclosporin and Tacrolimus: Oral and IV
  2. Sirolimus: oral only
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16
Q

PK of cyclosporin

A

Variable absorption: erratic bioavailability

Metabolised by CYP450

Victim of drug-drug interactions

17
Q

Is nephrotoxicity more common with ciclosporin or tacrolimus?

A

Ciclosporin

Hirsuitism
Gingival hyperplasia

18
Q

Tacrolimus specific side effects

A

Alopecia
More commonly hyperglycaemia

19
Q

Sirolimus side effects

A

Myelosuppression eg. thrombocytopaenia

Hyperlipidaemia
Hepatotoxicity
Diarrhoea

20
Q

Signs of toxicity in ciclosporin and tacrolimus use

A

Nephrotoxicity
HPT
Neurotoxicity
Hyperglycaemia
HyperK
Hyperlipid

21
Q

How does MMF work?

A

It is an antiproliferative

Cells need purines and pyrimidines for nucleic acid synthesis

there are two pathways to do this: De Novo and Salvage

De Novo pathway needs IMPDH to work.

MMF converts to MMA and this INHIBITS IMPDH, therefore, no purine can be made for DNA synthesis

T & B cells rely solely on this De Novo pathway, T cells can not proliferate and B cells can not produce antibody

22
Q

Clinical use of MMF

A

Liver, kidney, heart transplants

Combined with low dose cyclosporin to prevent nephrotoxicity (can use a lower dose of ciclosporin if combined with MMF)

Autoimmune (lupus nephritis)

23
Q

Signs of MMF toxicity

A

GIT disturbances

Myelosuppression

24
Q

What is an ideal transplant medication combination to suppress the immune system?

A

Use low doses of several drugs

Avoid over immunosuppression

25
Q

Cytotoxic Drugs MOA

Eg. Methotrexate

A

Cytotoxic drug
Inhibits Dihydrofolate reductase: reduced synthesis of purines and nucleic acids

Suppresses inflammation and cell activity and replication

Essentially:It acts at the level of the cell, destroying the cell itself by inhibiting the cell’s ability to synthesis proteins, divide and replicate (less T cell production)

26
Q

Clinical uses of methotrexate

A

Cancer: acute leukaemia, non-Hodgkin’s lymphoma, solid tumours (sarcoma) via antiproliferative action

Autoimmune: psoriasis, RA

Haematopoietic stem cell transplantation

Ectopic pregnancy

27
Q

Pharmacokinetics of Methotrexate

A

IV, oral route: good tissue distribution

Bioavailability is saturable: oral bioavail. is erratic at moderate to high doses

Metabolised in liver
Elim. renally so need to adjust according to eGFR

28
Q

Methotrexate contraindications

A

Blood disorders (neutropaenia)

Renal/Hepatic disease

Herpes/Varicella infection (past and present)

Serous effusions

Pregnancy/lactation

29
Q

Adverse effects methotrexate

A

BM suppression
Mucosal ulceration
Derm: alopecia, rash, pigmentation, urticaria

Liver and Renal Toxicity

hyperuricaemia

Pulm. pneumonitis

30
Q

Azathioprine: What is it and MOA

A

Cytotoxic drug

Prodrug of mercaptopurine, which interferes with purine nucleic acid metabolism, disrupting DNA synthesis and T cell proliferation and is used in the management of rheumatic diseases and organ transplantation

31
Q

sulfasalazine MOA

A

Cytotoxic drug

Interferes with activity of T-lymphs
Inflam. bowel disease and RA

32
Q

Hydroxychloroquine MOA

A

Antimalarial drug also cytotoxic

RA and SLE

33
Q

Cyclophosphamide MOA

A

alkylating agent that breaks DNA dont ask me how

Leukaemia and lymphoma treatment

34
Q

Monoclonal Antibodies

A

TNF-A inhib: Infliximab, Adalimumab, Etanercept

Anti-B cell antibody: Rituximab CD20 molecules on B cells

IL-2 receptor inhibitors: Basiliximab

High specificity

35
Q

Indications for Monoclonals

A

TNF-A inhib: RA, Psoriasis, Chrons

Anti-B cell antibodies: RA, lymphoma

IL-2 recep inhibitors: prevent organ rejection

36
Q

Issues associated with Monoclonals

A

Hypersensitivity
Serum sickness
Autoantibodies
Infections: TNF-A INHIB CAUSE TB
Cost