Drugs Mechanisms Of Action

Question 1

Amlodipine MOA

Answer 1

Dihydropyridine calcium channel blocker on vascular smooth muscle and afferent arterioles.
Arteriolar vasodilation and reduces afterload.

Question 2

Dexamethasone MOA

Answer 2

Suppresses migration of neutrophils. Decreases lymphocyte colony proliferation. Down regulates Fc receptors on macrophages, preventing release of proinflammatory cytokines IL-1 and IL-6

Question 3

Dexamethasone Side effects

Answer 3

PUPD, dull dry coat, weight gain, panting, vomiting, diarrhoea, elevated liver enzymes, GI ulceration, hypercoagulability, hyperlipidemia, hypokalemia, muscle wasting, calcinosis cutis.

Question 4

Clopidogrel MOA

Answer 4

Clopidogrel active metabolite (thiol compound) binds selectively to platelet surface ADP receptor P2Y12 and irreversibly alterrs the receptor for the lifespan of the platelet, which prevents ADP-mediated platelet activation and decreased subsequent platelet aggregation.

Question 5

Clopidogrel Side effects

Answer 5

Vomiting, anorexia, diarrhoea, bruising and bleeding.

Question 6

Mycophenalate MOA

Answer 6

Inhibits inosine monophosphate dehydrogenase (IMPDH). This is a rate limiting enzyme in de novo synthesis of guanosine nucleotides. As T cells and B cells are depedent on de novo synthesis of purine (e.g. guanosine), and unlike other cells, cannot use salvage pathways. Proliferative responses of T and B cells are inhibited. Suppression of B cell antibody formation occurs, thus inhibiting both cell mediated and humoral immune responses.

Question 7

Mycophenolate Side effects

Answer 7

Diarrhoea, vomiting, anorexia, lethargy, reduced activity, lymphopenia, increaseds rates of dermal infections.

Question 8

Cyclosporin MOA

Answer 8

Calcineurin inhibitor, immunosuppressive for cell-mediated immune responses. Binds to T cell cyclophilin and blocks calcineurin-mediated T cell activation. Inhibits cytokine production and release and IL 3/4, TNF-alpha.

Question 9

Cyclosporin Side effects

Answer 9

GI effects, gingival hyperplasia, altered glucose metabolism, DM, hypertrichosis.

Question 10

Cytarabine MOA

Answer 10

Cytarabine is converted intracellularly into aracytidine triphosphate, which competes with deoxycytidine triphosphate to inhibit DNA polymerase, resulting in inhibition of DNA synthesis.

Question 11

Cytarabine Side effects

Answer 11

Myelosuppression, GI effects, hepatoptoxicity.

Question 12

Dobutamine MOA

Answer 12

Beta-1 adrenergic agonist. Mild beta-2 and alpha-1 effects which balance each other. Does NOT cause release of norepinephine. Mild chronotropic, arrhythmogenic and vasodilative effects.

Question 13

Dobutamine Side effects

Answer 13

Can cause tachycardia at higherdoses. Can increase myocardial oxygen demand. Facial twitching and seizures.

Question 14

Dopamine MOA

Answer 14

Precursor to norepinephrine. Acts indirectly on alpha and beta receptors. Also has peripheral dopaminergic effects. Low dose 5-10ug/kg/min will have primarily beta-1 effects, positive cardiac inotrope. Dose 10-15ug/kg/min will have both alpha-1 and beta-1 effects, although alpha-1 effects predominate.

Question 15

Dopamine Side effects

Answer 15

Nausea, vomiting, ectopic beats, tachycardia, hypotension, hypertension, dyspnea, vasoconstriction.

Question 16

Tranexamic acid MOA

Answer 16

Blocks lysine-binding site on plasminogen. Subsequently blocks binding of plasminogen to fibrin and therefore prevents breakdown of fibrin, prolonging lifespan of formed clots.

Question 17

Tranexamic acid Side effects

Answer 17

Vomiting, diarrhoea, musculoskeletal pain, seizures reported, thrombosis, visual changes in humans.

Question 18

Amlodipine Side effects

Answer 18

Inappetence, lethargy, hypotension, diffuse peripheral oedema. Gingival hyperplasia long term.

Question 19

MOA heparin

Answer 19

Activates antithrombin III, inhibits thrombin and factor Xa preventing formation of fibrin clots

Question 21

MOA of L-asparaginase

Answer 21

Anti-neoplastic. Cancer cells rely on exogenous asparagine. The L-asparaginase breaks down asparagine into ammonia and aspartic acid.