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Sem. B - Pharmacology > Pharmacodynamics > Flashcards

Flashcards in Pharmacodynamics Deck (20)
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1

What is an Agonist?

A drug that binds to a receptor to stimulate a response

2

What is an Antagonist?

A drug that binds to a receptor to block stimulation

3

Adrenaline

  • It's a sympathomimetic
  • Has positive inotropic (cardiac contraction) and chronotropic (affecting rate) effects
  • Agonist at both alpha- & beta-adrenergic receptors (a1, ß1 & ß​2 receptors):
    • a1 & ß1 → (1) heart
    • ß2 → (2) lungs

4

Amiodarone Hydrochloride

  • Class III antiarrhythmic
  • Primary effect is to block potassium channels
    • does also block sodium and calcium too
  • Prolongs phase 3 of the cardiac action potential

5

Aspirin

  • Blocks COX 2 which is used in the synthesis of thromboxane (a product made by platelets to make blood clot)
  • Aspirin inhibits platelet activation so it's an antiplatelet

6

Atropine Sulfate

  • An acetylcholine (Ach) antagonist (anticholinergic)
    • also antimuscarinic agent
  • Blocks the action of Ach at the SA node
  • SA node will revert to its normal rhythm of 60-100 (normocardic)

7

Chlorphenamine

  • Antihistamine - H1 receptor antagonist (tech. inverse histamine agonist)
  • Also an anticholinergic
  • Histamine release due to inflammatory response in anaphylaxis has caused loss of tone in blood vessels
  • Binds to H1 receptor blocking action of endogenous histamine
  • Prevents further histamine release but will not reverse loss of vascular tone that has already occurred

8

Diazepam

  • Anticonvulsant
  • Benzodiazepine - sedative & hypnotic
  • CNS depressant
  • Anxiolytic
  • Enhances GABA post synaptically (agonist)
  • GABA is the primary inhibitory neurotransmitter of the CNS

9

Glucose

  • Carbohydrate which helps produce energy and heat

10

Glyceryl Trinitrate (GTN)

  • Potent vasodilator as the body converts it to nitric oxide
  • Relaxes inner muscles of the blood vessels, causing vessels to widen
    • this reduces after-load and pre-load
  • This will the increase blood flow and lower blood pressure

11

Hydrocortisone

  • Works at cortisol receptor sites all over the body
  • Glucocorticoid with anti-inflammatory properties
    • reduce inflammation in asthma & anaphylaxis
    • reduce overall length of asthma attack
    • reduce likelihood of biphasic response in anaphylaxis
  • In adrenal crisis it mimics action of cortisol (steroid hormone) which is lacking during crisis

12

Ibuprofen

  • Blocks cyclooxygenase (COX) 1 & COX 2
    • COX enzymes are responsible for creating a hormone like substance called prostaglandins
  • Prostaglandins produced by COX 1 responsible for producing the lining of the stomach
  • Prostaglandins produced by COX 2 responsible for inflammation and fever
  • Nonsteroidal anti-inflammatory drug
  • Also classed as an analgesic and antipyretic

13

Ipratromium Bromide

  • Antagonist at muscarinic receptors in the lungs

14

Morphine

  • works on CNS binding to same receptor sites as our endogenous (naturally occuring - endorphins, dynorphins & enkephalins) opioids
  • agonist at mu (best effect), kappa & delta receptors
  • receptors are found in the stomach, brain & spine
  • binding of morphine to receptors blocks the transmission of nociceptive signals
  • activates signalling of pain-modulating neurons in the spinalcord and inhibits transmission from primary afferent nociceptors to the dorsal horn sensory projection cells

15

Ondansetron

  • Reduces activity of the vagus nerve, which de-sensitizes the chemoreceptor trigger zone (vomiting centre) in the medulla oblongata
  • Blocks serotonin (5HT) receptors - specifically 5HT3

16

Paracetamol

  • Blocks COX 3
  • Works centrally in the body potentially acting on the hypothalamus
  • Inteferes with prostaglandin production
  • This produces peripheral vasodilation resulting in increased blood flow through the skin, sweating and heat loss

17

Salbutamol

  • It's a ß2 adrenoreceptor agonist
  • Also referred to as a short acting beta agonist (SABA)
  • Mimics adrenaline release from the sympathetic nervous system
  • Relaxes smooth muscle causing bronchodilation
  • Can occasionally 'spill over' into ß1 receptors of the heart and cause tachycardia

18

Glucagon

  • Binds to Glucagon receptors in the liver allowing glycogen stores to be converted into glucose then released into the blood stream

19

Syntometrine

  • Works at Oxytocin & 5HT receptors mostly in the uterus

20

Nitrous Oxide (Entonox)

  • Acts on potassium channels
  • Has effects on other receptor sites, eg. GABA, opiate, 5HT