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Flashcards in Mode Of Action Deck (64):
1

Insulin

Stimulates glucose uptake from circulation into tissues, glycogen, lipid and protein synthesis. Inhibits gluconeogenesis and ketogenesis

2

Sulphonylureas (Gliclazide)

Stimulates pancreatic insulin secretion by blocking ATP-dependant K+ channels causing depolarisation and opening of voltage gated Ca2+ channels

3

Biguanides (Metformin)

Increases response to insulin - suppresses hepatic glucose production, increases uptake and utilisation and suppresses intestinal absorbtion

4

Thyroxine

Replace endogenous hormones

5

Anti-Thyroid (Carbimazole)

Pro-drug metabolised to thiamazole to inhibit organification of iodine and coupling of iodothyronine which suppresses synthesis of thyroid hormone

6

Bisphosphonates (Alendronate)

Reduce bone turnover by inhibiting osteoclasts

7

Mineralocorticoid (Fludrocortisone)

Activates mineralocorticoid receptor to increase ion and H2O transport to raise extracellular volume and BP - lowering K+ levels

8

NAIDs (Diclofenac)

Inhibit synthesis of prostaglandins from arachidonic acid by inhibiting COX enzyme

9

Opiates (Codeine)

Metabolised in the liver to produce morphine which agonises Opioid U-receptors

10

Morphine

Activates Opioid U-receptors in CNS to reduce neuronal excitability.
Blunts response to hypoxia and hypercapnia in the medulla.
Reduce cardiac work and O2 demand

11

Paracetamol

Not Understood - weak COX 1 inhibitor

12

Xanthine-Oxidase-Inhibitor (Allopurinol)

Inhibits X-O to reduce metabolism of Xanthine to uric acid

13

Alpha-Blockers (Doxazocin)

Selective for a-adrenoreceptors found in smooth muscle cells to cause vasodilation and fall in BP

14

5-alpha-reductase Inhibitors (Finasteride)

Reduce the size of the prostate by inhibiting intracellular 5a-reductase enzyme that converts testosterone into dihydrotestosterone which stimulates pancreatic growth

15

Penicillins (Amoxicillin)

Inhibit the enzymes responsible for cross linking peptidoglycan in bacterial cell wall

16

Cephalosporins (Cephradine)

Inhibit the enzymes responsible for cross linking peptidoglycan in bacterial cell wall

17

Trimethorpim

Inhibit bacterial folate production

18

Nitrofurantoin

Metabolised by nitrofuran reductase to active component that damages bacterial DNA

19

`Tetracyclines (Doxyclycline)

Bind to 30s ribosome to inhibit protein synthesis and tRNA unable to bind to mRNA

20

Aminoglycosides (Gentamicin)

Irreversibly bind to 30s ribosome to inhibit bacterial synthesis

21

Macrolides (Erythromycin)

Bind 50s ribosome to block translocation

22

Quinolones (Ciprofloxacin)

Inhibit bacterial DNA synthesis

23

Anaerobic - Metronidazole

Passive diffusion into cell, then reduced to produce nitroso free radical which bind to DNA and reduces synthesis. (Aerobic bacteria unable to reduce metronidazole)

24

Glycopeptides (Vancomycin)

Inhibits growth and cross linking of peptidoglycan chains

25

Antacids (Gaviscon)

Buffer the stomach

26

H2-antagonists (Ranitidine)

Antagonise histamine receptors in parietal cells which secrete H+ into stomach

27

PPI (Omeprazole)

Irreversibly inhibit H+/ATP-ase in parietal cells

28

Anti-diarrhoea (Loperamide)

Opioid that doesn't penetrate CNS - agonist of opioid u-receptors in GI tract to increase non-propulsive and decrease propulsive movements - slower transport of bowel contents

29

Laxative (Senna)

Increase water and electrolyte secretion, increasing colonic content and stimulating peristalsis

30

Aminosalicylate - (Mesalazine)

Releases 5-aminosalicylic acid which has anti-inflammatory effects

31

Anti-emetics (Metoclopramide)

Blocks dopamine receptors to reduce smooth muscle and LOS relaxation along with inhibiting the 'vomiting centre' in the medulla

32

Loop Diuretics (Furosemide)

Inhibit the Na+/K+/2Cl- transporter on the descending loop of Henle to reduce absorption and therefore water absorption.

33

Thiazide Diurects (Bendroflumathiazide)

Inhibit Na+/Cl- co-transporter in distal convoluted tubule to prevent reabsorption of Na and associated water - this is compensated for in the long term but does cause vasodilation

34

Potassium Sparing Diuretics (Spironolactone)

Competes with aldosterone which increases Na+ and H2O excretion and K+ retention

35

Beta-Blockers (Atenolol)

Block B1-adrenergic receptors on the heart to reduce force of contraction and speed of conduction

36

Calcium Antagonist (Diltiazem)

Block Ca2+ entry into cardiac cells, causing relaxation and vasodilation in arterial smooth muscle - reduces arterial pressure and myocardial contractility. Also slows contraction across the AV node

37

ACE Inhibitors (Ramipril)

Blocks conversion of AT1 to AT2 which blocks the action of the vasoconstrictor and reduces aldosterone secretion

38

AT1 Blockers (Losartan)

Block the action of AT2 on the AT1 receptors which reduces peripheral vascular resistance - work particularly on the efferent glomerular arteriole

39

Nitrates (Isorbide Mononitrate)

Converted to Nitric Oxide which increases guanosine monophosphate synthesis and reduces intracellular Ca2+ in vascular smooth muscle cells - causing relaxation

40

Cardiac Glycosides (Digoxin)

Increases Vagal tone to reduce contraction at the AV node and inhibits Na+/K+ ATP-ase pumps causing accumulation of Na+ in cells which causes accumualtion of Ca2+ which increases contractile strength

41

Anti-dysrhythmics (Amiodarone)

Blocks Na+/Ca2+/K+ channels along with antagonism of alpha and beta adrenergic receptors which reduces spontaneous depolarisation, slows conduction velocity and increases resistance to AV node depolarisation.

42

Aspirin

Irreversibly inhibits COX to reduce production of the pro-aggregatory factor Thromboxane from Arachidonic acid - reducing platelet aggregation

43

Clopidogrel

Irreversibly binds to Adenosine Diphosphate receptors on the surface of platelets to reduce aggregation (Process is synergistic with aspirin)

44

Thrombolytics (Tissue Plasminogen Activator)

Cleaves Zymogen Plasminogen at the Arg561-Val562 bond to convert it to plasmin which breaks down clots

45

Heparins (Enoxaparin)

Enoxaparin - Inhibits the action of Thrombin and Factor Xa to prevent formation of blood clots
Fondaparinux - Only FXa

46

Novel Anticoagulants (Rivaroxaban)

Direct Factor Xa inhibitor

47

Oral Anticoagulants (Warfarin)

Inhibits hepatic production of vitamin K dependant coagulation factors by inhibiting the enzyme vitamin K epoxide reductase to prevent Vit K from being reduced to its active form

48

Statins (Simvastatin)

Inhibit 3-hydroxy-3methyl-glutaryl co-enzyme A reductase which is used in making cholesterol. Also decrease hepatic production and increase clearance from the blood of LDL.

49

Beta-2-agonists (Salbutamol)

B2 receptors are in smooth muscle of bronchi, GI tract, Uterus and blood vessels - stimulation causes smooth muscle relaxation.
Also stimulates Na+/K+ ATP-ase pumps causing a shift of K+ into cells (Treat Hyperkalaemia)

50

Anticholinergics (Tiotropium)

Bind to muscarinic receptor to inhibit acetylcholine to reduce smooth muscle tone and secretions

51

Corticosteroids (Prednisolone)

Bind to cytosolic glucocorticoid receptors which then translocate to the nucleus and bind to glucocorticoid-response elements which regulate gene expression - Up-regulate anti-inflammatory genes and down-regulate pro-inflammatory genes

52

Mucolytics (Carbocysteine)

Reduce goblet cell hyperplasia and prevent conversion of serous cells to mucus cells

53

Theophylline

Xanthine derivative that relaxes smooth muslce to cause bronchodilation

54

Oxygen

Accelerates reabsorbtion of gas in Pneumothorax by reducing the fraction of N2 in the aveoli, increasing its diffusion out of the body

55

L-dopa (Modapor/Sinemet)

L-dopa can cross the BBB to increase conc and act as a dopamine receptor agonist and provide stimulation

56

Anticonvulsants (Phenytoin)

Reduces neuronal excitability and electrical conductance among brain cells by appearing to bind Na+ channels in their inactive state

57

Carbamazepine

Inhibits neuronal Na+ channels, stabilising their resting potentials and also blocks synaptic transmission in the trigeminal nucleus

58

Sodium Valproate

Appears to be a weak inhibitor of Na+ channels and also increases brain contents of y-aminobutyric acid (GABA) which is an inhibitory neurotransmitter

59

Lamotrigine

Na+ channel blocker that inhibits sustained firing of neurons and inhibits release of glutamate

60

Levitaracetam

Interacts with the synaptic vesicle protein 2A

61

Tricyclics (Amitryptilline)

Inhibits neuronal reuptake of serotonin and noradrenaline from the synaptic cleft, increasing their availability for neurotransmission by blocking muscarinic, histamine, a-adrenergic and dopamine receptors

62

SSRI's (Citalopram)

Inhibit neuronal reuptake of serotonin but not noradrenaline

63

Benzodiazepines (Diazepam)

Target the y-aminobutyric acid type A receptors (GABA(a)) which is a chloride channel that opens in response to binding by GABA - the main inhibitory neurotransmitter - reducing neuronal excitability

64

Acetylcholinesterase Inhibitors (Donepezil)

Inhibits the enzyme responsible for the breakdown of acetylcholine which causes an increase in availability in the synapses of the brain allowing for greater conduction and brain activity.