Medications Flashcards
Ondansetron MOA
Serotonin (5HT) is released from enterochromaffin cells ( stomach/ small intestine) in response to noxious stimuli
5HT3 receptors are activated, stimulating the vagus nerve and subsequently the vomiting centre
Ondansateron is a 5HT3 antagonist which interferes with this process at multiple sites ( stomach/ vagus nerve/ vomiting centre)
Metoclopramide MOA
A highly effective but highly un- refined
Multiple sites of action, D2/ DA2 receptors (dopaminergic)
Serotonergic (5HT3), cholinergic (M1) and other interaction within the CNS
Serotonergic (5HT4) agonist effect and cholinergic effects also promote gastric emptying by inhibiting the relaxation of smooth muscle and increasing peristalsis which can be helpful in some circumstances
Adrenaline
Mediated through beta 2 receptor that is found on surface of airway smooth muscle cells
Action is two pronged, firstly reduces the amount of cAMP, which decreases amount of calcium in cytoplasm, this reduction reduces the contractions
Salbutamol
(beta 2 agonist)
Binds to beta 2 receptor, increasing Camp which reduces calcium and interferes with actin myosin interaction causing bronchodilation
Ipatropium
muscarinic antagonist
Blocks muscarinic acetylcholine receptors causing decreased smooth muscle contractility resulting in bronchodilator and decreased respiratory tract secretions
Atropine
When atropine binds to the M2 receptor it blocks the effects of acetylcholine, increases in cAMP level and increases in funny current and therefor heart rate and output
Hydrocortisone
Alters interaction within the cell changing DNA processes which dampens the effect of the inflammatory response.
Blocks formation of arachidonic acid, reducing amount of late mediators released
Reduced function and activation of b cells and t helper cells
Magnesium sulphate
Reduces calcium influx into cells producing skeletal and smooth muscle relaxation and reduced cardiac muscle contractility and excitability.
Smooth muscle relaxer and can alleviate bronchoconstriciton
Lignocaine 1% nerve block
Blockage of voltage gated sodium channels on the internal surface of nerve cell membranes leading to a reversible prevention of nerve depolarisation
Midazolam
Binds to gaba A receptors at different allosteric sites, this facilitates the action of gaba and enhances its inhibitory effects, increases opening of chloride channels and chloride floods into cell
Prevents depolarisation prevents action potential from continuing
Mirtazapine
Blocks postsynaptic serotonin receptors and presynaptic auto receptors and H1 agonists
Droperidol/ haloperidol
Antagonise D1 and D2 receptors, block dopamingeric transmission in various parts of the brain and leads to CNS depression
Benzylpenicllin
Inhibits bacterial cell wall synthesis, inhibits the cross linking of the cell wall without cross links the cell wall is destroyed allows water to flow in and cells Burt’s and dies
Ceftriaxone
Inhibits cell wall synthesis, is susceptible to gram positive and negative bacteria
Statins
HMG COA reductase inhibitors
Reduce lipids by blocking the production of cholesterol in the liver
Amiodarone
Interacts with sodium, calcium and potassium affecting the ion movement. Prolongs refractory period and duration of action potential, decreases sinus node automaticity, slows atrioventricular conduction
For VT & VF
Adenosine
Simulates A1 receptors on atrium and on SA and AV node, pro kings refractory period increased potassium efflux and decreases calcium efflux. briefly stops electrical conductivity of the heart allowing SA nose to take over
Digoxin
Inhibits sodium and potassium adenosine triphosphate pump in myocardium membrane leading to increased intracellular calcium, activated actin and myosin, greater force of contraction, shortens action potential, reduces av nodal conduction and decreased HR
GTN
Interacts with vascular smooth muscles, converts to nitric oxide, increases levels of cGMP, reduces calcium levels, reduces actin and myosin interaction, relaxation of vascular smooth muscles and decrease in blood pressure
Aspirin
Targets platelet aggregation phase, inhibits cycloxygenase, prevents synthesis of thromboxane and prostacyclin and other prostaglandins.
Reduces platelet activation, reduces recruitment reduces aggregation
Clopigogeel
Targets platelet aggregation phase, ADP increases intracellular calcium levels via P2Y12 and P2Y1 receptors
Lowers calcium levels prevents shape change prevents degranulation
Heparin
Binds to and enhances the ability of naturally occurring anti thrombin 3, deactivates factors 10a and 2a, deactivation interrupts fibrin formation
Tenecteplase
Fibrinolytic agent, clever or degrades the fibrin dissolution of the clot
Tranexamic acid
Synthetic derivative of lysine, binds to plasminogen, inhibits normal plasmin formation, slows breakdown of clots, helps prevent bleeding
Frusemide
Decreased preload via preventing the reabsorption of water, increases urine output
Inhibits renal sodium reabsorption
Insulin
Increase or restore the ability to metabolise glucose by enhancing glucose uptake
Glucagon
Binds to glucagon receptors in the liver, activate cAMP, stimulate glycogenolysis, releases glucose from glycogen stores
Oxytocin
Activates oxytocin receptors, increases calcium release, increase muscle contraction
