04 Drugs affecting the immune response Flashcards
4.01 CALCINEURIN INHIBITORS
Immunosuppressants: ciclosporin, tacrolimus, pimecrolimus - actions
binding to cytosolic immunophilins to form a complex that inhibits calcineurin
this reduces activation and proliferation of T cells and production of cytokines
4.01 CALCINEURIN INHIBITORS
Immunosuppressants: ciclosporin, tacrolimus, pimecrolimus - MOA
inhibits calcineurin (calcium-dependent phosphatase) which normally activates the transcription of interleukin-2 (IL-2)
4.01 CALCINEURIN INHIBITORS
Immunosuppressants: ciclosporin, tacrolimus, pimecrolimus - abs/distrib/elim
ciclosporin and tacrolimus can be given orally or by IV infusion, metabolised in the liver by the P450 3A enzyme system
topical formulations of tacrolimus and pimecrolimus have low systemic absorption
4.01 CALCINEURIN INHIBITORS
Immunosuppressants: ciclosporin, tacrolimus, pimecrolimus - clinical use
used to prevent rejection of organ and tissue transplants and for prevention of graft v host disease
can be useful in autoimmune diseases
topical use for atopic dermatitis (tacrolimus or pimecrolimus)
4.01 CALCINEURIN INHIBITORS
Immunosuppressants: ciclosporin, tacrolimus, pimecrolimus - adverse effects
myelosuppression and risk of infection
nephrotoxicity
can cause hypertension, hepatotoxicity, tremor, paraesthesia
4.02 ANTIPROLIFERATIVE IMMUNOSUPPRESSANT
Azathioprine - actions
reduces the clonal proliferation of T and B cells during the induction phase of the immune response
4.02 ANTIPROLIFERATIVE IMMUNOSUPPRESSANT
Azathioprine - MOA
interferes with purine synthesis and has cytotoxic action on dividing cells
4.02 ANTIPROFILERATIVE IMMUNOSUPPRESSANT
Azathioprine - abs/distrib/elim
given orally or by IV infusion
metabolised to mercaptopurine, which is the cytotoxic moiety acting by interfering with purine nucleotide metabolism
mercaptopurine is inactivated by xanthine oxidase
4.02 ANTIPROLIFERATIVE IMMUNOSUPPRESSANT
Azathioprine - clinical use
used to prevent rejection of organ and tissue transplants and for prevention of graft v host disease
also used in chronic inflammatory and autoimmune diseases (e.g. rheumatoid arthritis, inflammatory bowel disease)
4.02 ANTIPROLIFERATIVE IMMUNOSUPPRESSANT
Azathioprine - adverse effects
myelotoxicity (dose-related - monitoring is required)
GIT disturbances, hypersensitivity reactions (skin rashes, arthralgia, etc.)
4.03 ANTIPROLIFERATIVE IMMUNOSUPPRESSANT
Mycophenolate mofetil - actions
selectively restrains the clonal proliferation of T and B cells and reduces the production of cytotoxic T cells
4.03 ANTIPROLIFERATIVE IMMUNOSUPPRESSANT
Mycophenolate mofetil - MOA
selectively inhibits inosine monophosphate dehydrogenase which is responsible for de novo purine synthesis specifically in T and B lymphocytes (other cells can generate purines by another pathway)
4.03 ANTIPROLIFERATIVE IMMUNOSUPPRESSANT
Mycophenolate mofetil - abs/distrib/elim
given orally or by IV infusion
metabolised to mycophenolic acid which is the active moiety
4.03 ANTIPROLIFERATIVE IMMUNOSUPPRESSANT
Mycophenolate mofetil - clinical use
used to prevent rejection of organ transplants, usually in combination with ciclosporin and glucocorticoids
also used in a wider range of autoimmune diseases (e.g. lupus, vasculitis)
4.03 ANTIPROLIFERATIVE IMMUNOSUPPRESSANT
Mycophenolate mofetil - adverse effects
GIT, CVS and respiratory system disturbances
hepatitis, pancreatitis
tremor, dizziness
flu-like syndrome
4.04 ANTIPROLIFERATIVE ANTIBIOTIC
Sirolimus (rapamycin) - actions
inhibits the clonal proliferation of T and (more particularly) B cells
decreases immunoglobulin production
4.04 ANTIPROFILERATIVE ANTIBIOTIC
Sirolimus (rapamycin) - MOA
blocks the response of precursor cells to interleukin-2 (IL-2) by binding to a cytosolic protein (FK-binding protein 12) to form a complex that inhibits the activation of mammalian target of rapamycin (mTOR) kinase - thus suppressing activation of T and B cells
4.04 ANTIPROLIFERATIVE ANTIBIOTIC
Sirolimus (rapamycin) - abs/distrib/elim
given orally
metabolised by P450 3A in the liver - therefore many drug interactions
4.04 ANTIPROLIFERATIVE ANTIBIOTIC
Sirolimus (rapamycin) - clinical use
used to prevent rejection of organ transplants (particularly renal because, unlike ciclosporin, it has no renal toxicity) usually in combination with ciclosporin or glucocorticoids
4.04 ANTIPROLIFERATIVE ANTIBIOTIC
Sirolimus (rapamycin) - adverse effects
myelosuppression (important)
hyperlipidaemia
venous thromboembolism
diarrhoea
rash
osteonecrosis
4.05 GLUCOCORTICOIDS
Prednisolone, dexamethasone, hydrocortisone, triamcinolone - actions
inhibits the clonal proliferation of T and B cells and macrophage activation
(other actions: reduces chronic inflammation, autoimmune and hypersensitivity reactions, various metabolic effects, negative feedback action on anterior pituitary and hypothalamus)
4.05 GLUCOCORTICOIDS
Prednisolone, dexamethasone, hydrocortisone, triamcinolone - MOA
glucocorticoids (GCs) interact with intracellular receptors to inhibit the transcription of specific genes that code for various cytokines esp. IL-2
4.05 GLUCOCORTICOIDS
Prednisolone, dexamethasone, hydrocortisone, triamcinolone - abs/distrib/elim
given orally, by injection or topically
the main effects occur only after 2-8h because protein synthesis of mediators and enzymes is required