PHARMACOLOGY Flashcards
what drug class is azathioprine?
an antagonist of purine metabolism/ an immunosuppressant
what does azathioprine do?
it acts to inhibit purine synthesis which inhibits DNA and RNA synthesis which leads to an inhibition in cell proliferation. This leads to a decrease in production in white blood cells leading to immunosuppression.
what is immunosuppression?
prevention or weakening the body’s ability to produce an immune response
what is azathioprine’s mechanism of action?
incorporation of thiopurine analogues into DNA structures which causes chain termination and cytotoxicity.
what are some indications of azathioprine?
autoimmune conditions, arthritis, Crohn’s disease, transplant rejection, high TMPT activity, myasthenia gravis
what is TMPT? what does it do?
thiopurine S-methyltransferase.
it breaks down thiopurine drugs which suppress the immune system.
what are the side effects of azathioprine?
bone marrow depression, increased risk of infection, leucopenia, pancreatitis and thrombocytopenia.
what should azathioprine not be given in conjunction with?
purine analogues (antimetabolites that mimic the structure of metabolic purines)
what must be monitored with long term treatment with azathioprine?
blood tests and monitoring for signs of myelosuppression
what drug class is cyclosporin?
an immunosuppressive agent/ a cyclophilin binder
what is the mechanism of cyclosporin?
it binds to cyclophilin which causes inhibition of calcineurin which is responsible for activating the transcription of IL-2. this causes the reversible inhibition of immunocompetent lymphocytes in the G0 or G1 phase of the cell cycle. T lymphocytes are preferentially inhibited.
what are the indications of cyclosporin?
organ and bone marrow transplantation
what are the common side effects of cyclosporin?
eye inflammation, appetite decreased, diarrhoea, fatigue, fever, flushing, GI discomfort, trembling, vomiting etc….
how can cyclosporin be administered?
parenteral, eyes, oral
how is azathioprine administered?
intravenous and orally
what drug class is clopidogrel?
a P2Y12 antagonist/ anti-platelet therapy agent
what is clopidogrel’s mechanism of action? What enzyme does it require?
it irreversibly blocks P2Y12 receptors and therefore blocks the binding site of ADP which is a platelet agonist and can act as a secondary agonist that is critical to complete platelet activation. this means the activation of GP11b/111a receptor is reduced leading to a reduction in fibrinogen binding and thrombus formation.
CYP450 enzymes to produce the active metabolite as its a prodrug.
what are the indications of clopidogrel?
prevention of atherothrombi events
what are the side effects of clopidogrel?
diarrhoea, GI discomfort, haemorrhage and skin reactions
how is clopidogrel administered?
orally
what drug class is heparin?
an anticoagulant agent
how does heparin prevent the formation of fibrin?
heparin in combination with antithrombin2 can inhibit thrombosis by inactivating factor Xa and thrombin. Once active thrombosis has developed, larger amounts of heparin can inhibit further coagulation by inactivating thrombin and preventing the conversion of fibrinogen to fibrin.
how does heparin prevent the formation of stable fibrin clots?
it inhibits the activation of the fibrin stabilising factor
what are the indications of heparin?
pulmonary embolisms, arteriole occlusions, angina, deep vein thrombosis, thromboprophylaxis, haemodialysis, prevention of clotting
what are the side effects of heparin?
haemorrhage, heparin-induced-thrombocytopenia, skin reactions, thrombocytosis
how is heparin administered?
intravenously
what drug class is lepirudin?
anti-thrombin agent/ anticoagulant
what is the mechanism of action of lepirudin?
it forms a stable non-covalent complex with thrombin, preventing fibrinogen cleavage and initiation of the clotting cascade.
lepirudin has been withdrawn. what has it been replaced with?
dabigatran or apixaban
what is dabigatran?
a direct thrombin inhibitor
what is apixaban?
a factor Xa inhibitor
what are the indications for lepirudin?
heparin-induced thrombocytopenia (HIT) and associated thromboembolic disease
what are the side effects of lepirudin?
sudden numbness or weakness (especially on one side of the body), sudden headache, confusion, problems with speech, or balance; bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds; red or pink urine
how is lepirudin administered?
orally
what drug class is prednisolone?
a glucocorticoid receptor agonist/cotricosteroid/ immunosuppressant
what is prednisolone derived from? where is it metabolised?
it is derived from cortisone and is metabolised in the liver to prednisolone
what is prednisolone’s mechanism of action?
prednisolone can cross cell membranes and bind to cortisone receptors. this leads to changes in DNA transcription, reducing the production of inflammatory proteins. it can also affect cell membrane ion permeability and neurohormone production.
what are the indications for prednisolone?
COPD, croup, asthma, inflammation, allergic reactions, Crohn’s disease, myasthenia gravis etc…
what are the side effects of prednisolone?
anxiety, abnormal behaviour, cognitive impairment, Cushing’s syndrome, electrolyte imbalance, fatigue, Gi discomfort, headache…
how is prednisolone administered?
ear, eye, intra-articular, intramuscular and oral
what drug class is tetanus booster?
vaccination therapy
why must a tetanus booster be given?
to ensure a resistance to tetanus infection as we give an inactive tetanus which induces a weaker immune response
what does an inactive vaccine contain?
virus/bacterial particles which are grown in the lab but have been killed using heat or formaldehyde.
how can inactive vaccines be split into groups?
whole virus, split virus and subunit virus
when should the booster be given?
every 10 years but it can be given within 2 days of the patient’s injury if needed
what drug class is warfarin?
a vitamin K antagonist/ anticoagulant
what is warfarin used to prevent?
thromboembolic diseases e.g. venous thrombosis, thromboembolism, pulmonary embolism and ischemic stroke
why should you not take warfarin when pregnant?
as it can cross the placental barrier resulting in foetal bleeding, spontaneous abortions and neonatal death
describe warfarin mechanism of action?
it inhibits vitamin K reductase, reducing levels of the reduced form of vitamin k which is require for the production of coagulation factors II, IIV, IX and X and anticoagulant proteins C and S. depression of these coagulation factors results in decreased prothrombin levels, decreased thrombin generation and reduced ability to form a clot
what are the indications of warfarin?
Prophylaxis of embolisation in rheumatic heart disease, atrial fibrillation, after insertion of prosthetic heart valve, venous thrombosis and pulmonary embolism and
transient ischaemic attacks
what are the side effects of warfarin?
alopecia, nausea, vomiting
how is warfarin administered?
orally
