Session 8.1 - Immunosuppressants

Question 1

Azathioprine

Answer 1

Drug Class: Immunosuppressant

Mechanism of Action: Cleaved to form 6-MP. 6-MP is then metabolized by TPMT, and acts by decreasing DNA and RNA synthesis

Common Indicators: SLE, vasculitis, IBD, ‘steroid sparing’ drug

ADRs: Hepatitis, Bone marrow suppression, Increased risk of malignancy, Increased risk of infection

Important drug-drug rxns: none

Question 2

Ciclosporin

Tacrolimus

Answer 2

Drug Class: Immunosuppressant

Mechanism of Action: Active against T helper cells, preventing production of IL-2 via calcineurin inhibition

Common Indicators: Transplantation, atopic dermatitis, psoriasis

ADRs: Renal toxicity

Important drug-drug rxns: Inhibits CYP-450

Question 3

Mycophenolate mofetil

Answer 3

Drug Class: Immunosuppressant - anti-proliferative agent

Mechanism of Action: Inhibits Iosine Monophosphate Dehydrogenase (IMD), needed for Guanosine synthesis –> impairs B and T cell proliferation

Common Indicators: Transplantation, vasculitis

ADRs: Myelosuppression, Nausea, vomiting, diarrhoea, mucositis

Important drug-drug rxns: none

Question 4

Cyclophosphamide

Answer 4

Drug Class: DMARD

Mechanism of Action: Suppresses T and B cells by cross-linking DNA so that they can’t replicate

Common Indicators: Lymphoma, leukaemia, cancers, lupus nephritis
(this drug just wipes everything out)

ADRs: TOXIC: bladder cancer, lymphoma, leukaemia, infertility -> monitor FBC, adjust dose for renal impairment

Important drug-drug rxns: Activated by CYP-450

Question 5

Methotrexate

Answer 5

Drug Class: DMARD

Mechanism of Action: UNCLEAR MoA for non-malignant treatments (NOT Anti-folate action like for cancer treatment)- Maybe inhibits adenosine, T-cell activation

Common Indicators: Best for RHEUMATOID ARTHRITIS, pregnancy termination

ADRs: Mucositis, myelosuppression, hepatitis, cirrhosis

Important drug-drug rxns: none

Question 6

Sulphasalazine

Answer 6

Drug Class: DMARD

Mechanism of Action: Inhibits T Cell proliferation –> Inhibit IL-2 Production
- Reduced Neutrophils (reduced chemotaxis, degranulation)

Common Indicators: IBD

ADRs: Myelosuppression, hepatitis, rash

Important drug-drug rxns: none

Question 7

Rituximab

Answer 7

Drug Class: Anti-TNF agent

Mechanism of Action: B-lymphocyte Lytic Monoclonal Antibody -> antibody against CD20 Receptor on B cells

Common Indicators: RA, Chronic Lymphocytic Leukaemia

ADRs: SCREEN for latent TB before

Important drug-drug rxns: none