Mode Of Action Flashcards

1
Q

Insulin

A

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

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2
Q

Sulphonylureas (Gliclazide)

A

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

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3
Q

Biguanides (Metformin)

A

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

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4
Q

Thyroxine

A

Replace endogenous hormones

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5
Q

Anti-Thyroid (Carbimazole)

A

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

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6
Q

Bisphosphonates (Alendronate)

A

Reduce bone turnover by inhibiting osteoclasts

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7
Q

Mineralocorticoid (Fludrocortisone)

A

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

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8
Q

NAIDs (Diclofenac)

A

Inhibit synthesis of prostaglandins from arachidonic acid by inhibiting COX enzyme

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9
Q

Opiates (Codeine)

A

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

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10
Q

Morphine

A

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

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11
Q

Paracetamol

A

Not Understood - weak COX 1 inhibitor

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12
Q

Xanthine-Oxidase-Inhibitor (Allopurinol)

A

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

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13
Q

Alpha-Blockers (Doxazocin)

A

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

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14
Q

5-alpha-reductase Inhibitors (Finasteride)

A

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

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15
Q

Penicillins (Amoxicillin)

A

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

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16
Q

Cephalosporins (Cephradine)

A

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

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17
Q

Trimethorpim

A

Inhibit bacterial folate production

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18
Q

Nitrofurantoin

A

Metabolised by nitrofuran reductase to active component that damages bacterial DNA

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19
Q

`Tetracyclines (Doxyclycline)

A

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

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20
Q

Aminoglycosides (Gentamicin)

A

Irreversibly bind to 30s ribosome to inhibit bacterial synthesis

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21
Q

Macrolides (Erythromycin)

A

Bind 50s ribosome to block translocation

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22
Q

Quinolones (Ciprofloxacin)

A

Inhibit bacterial DNA synthesis

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23
Q

Anaerobic - Metronidazole

A

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

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24
Q

Glycopeptides (Vancomycin)

A

Inhibits growth and cross linking of peptidoglycan chains

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25
Q

Antacids (Gaviscon)

A

Buffer the stomach

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26
Q

H2-antagonists (Ranitidine)

A

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

27
Q

PPI (Omeprazole)

A

Irreversibly inhibit H+/ATP-ase in parietal cells

28
Q

Anti-diarrhoea (Loperamide)

A

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
Q

Laxative (Senna)

A

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

30
Q

Aminosalicylate - (Mesalazine)

A

Releases 5-aminosalicylic acid which has anti-inflammatory effects

31
Q

Anti-emetics (Metoclopramide)

A

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

32
Q

Loop Diuretics (Furosemide)

A

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

33
Q

Thiazide Diurects (Bendroflumathiazide)

A

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
Q

Potassium Sparing Diuretics (Spironolactone)

A

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

35
Q

Beta-Blockers (Atenolol)

A

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

36
Q

Calcium Antagonist (Diltiazem)

A

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
Q

ACE Inhibitors (Ramipril)

A

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

38
Q

AT1 Blockers (Losartan)

A

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

39
Q

Nitrates (Isorbide Mononitrate)

A

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

40
Q

Cardiac Glycosides (Digoxin)

A

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
Q

Anti-dysrhythmics (Amiodarone)

A

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
Q

Aspirin

A

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

43
Q

Clopidogrel

A

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

44
Q

Thrombolytics (Tissue Plasminogen Activator)

A

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

45
Q

Heparins (Enoxaparin)

A

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

46
Q

Novel Anticoagulants (Rivaroxaban)

A

Direct Factor Xa inhibitor

47
Q

Oral Anticoagulants (Warfarin)

A

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
Q

Statins (Simvastatin)

A

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
Q

Beta-2-agonists (Salbutamol)

A

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
Q

Anticholinergics (Tiotropium)

A

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

51
Q

Corticosteroids (Prednisolone)

A

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
Q

Mucolytics (Carbocysteine)

A

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

53
Q

Theophylline

A

Xanthine derivative that relaxes smooth muslce to cause bronchodilation

54
Q

Oxygen

A

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

55
Q

L-dopa (Modapor/Sinemet)

A

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

56
Q

Anticonvulsants (Phenytoin)

A

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

57
Q

Carbamazepine

A

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

58
Q

Sodium Valproate

A

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
Q

Lamotrigine

A

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

60
Q

Levitaracetam

A

Interacts with the synaptic vesicle protein 2A

61
Q

Tricyclics (Amitryptilline)

A

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
Q

SSRI’s (Citalopram)

A

Inhibit neuronal reuptake of serotonin but not noradrenaline

63
Q

Benzodiazepines (Diazepam)

A

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
Q

Acetylcholinesterase Inhibitors (Donepezil)

A

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.