Pharmocology Flashcards
Can you name the 7 drugs used in cardiac management
Aspirin
GTN
Ondansetron
Morphine
Furosemide
Amiodarone
Atropine
Can you name the 7 drugs used in cardiac management
Aspirin
GTN
Ondansetron
Morphine
Furosemide
Amiodarone
Atropine
Explain the pharmacology of Aspirin
Aspiring Is an anti-platelet drug, inhibiting the COX1 and COX2 enzymes
COX1 is responsible for prostaglandins formation, these are required to activate thromboxane.
Thromboxane attracts more platelets to it and activates the calciumm cascade in the platelets causing it to form fibrinogen dendrites
COX2 is responsible for the metabolism of arachidonic acid into prostaglandins, responsible for sensitising neurons to pain and causing inflammation and fever
Explain the pharmacology of GTN
GTN - Glyceral Trinitrate
It is a potent vasodilator
Once absorbed it undergoes denitrification where it becomes nitric acid
This nitric acid causes the increased production of cGMP in smooth muscle cells that line the arteries and veins, causing them to relax and allowing vasodilation to occur
Explain the pharmacology of Ondansetron
It is a highly specific serotonin 5-HT3 receptor agonist. It is used in the prevention and treatment of nausea and vomiting
It prevents serotonin released from the small intestine from binding and activating the vomiting reflex
Explain the pharmacology of Morphine
It binds to several opioid receptors in the CNS but most strongly the mu-opioid receptors
This mimics the effects of endorphins, which are responsible for analgesia and feelings of pleasure
However, strong affinity also causes respiratory depression and sedation to occur.
Morphine also causes the release of histamine which could account for its vasodilatory effect
Explain the pharmacology of Furosemide
Furosemide is a loop diuretic that inhibits sodium reabsorption by the distal and proximal tubules and also in the loop of Henle
This causes a decrease in circulatory pressure as water molecules follow the sodium
This can help relieve pulmonary oedema
Adult does is 40mg, YAS provides 50mg in 5ml so only 4ml to be given
Explain the pharmacology of Amiodarone
It is an antiarrhythmic drug that prolongs the duration of cardiac action potential
It blocks potassium currents that cause depolarisation of the heart
As a result, this increases the duration of the action potential as well as the effective refractory period for cardiac cells
Therefore, cardiac muscle cell excitability is reduced, preventing and treating abnormal rhythms
It also blocks sodium and potassium channels in cardiac muscle, acts to stabilise and reduce electrical irritability of cardiac muscle
The initial dose of Amiodarone is 300mg, 2 vials are needed
Ideally drawn up with 5% glucose
Explain the pharmacology of Atropine
It is a muscarinic receptor agonist that is used to inhibit the effects of excessive vagal activation of the heart.
It inhibits acetylcholine at parasympathetic neuro-effector sites
For paramedic use, it blocks vagal nerve activity on the heart causing increased HR
Atropine may also lessen the degree of partial heart bock when vagal activity is a etiologic factor
Should be administered as a rapid bolus
Which drugs would be used in the management of a STEMI?
Aspirin - 300mg chewed - sublingual
GTN - 2 sprays - 400-800mcg - sublingual
Ondansetron
Morphine
Oxygen if needed (<94%)
Which medications are stored in ampoules?
Adrenaline 1:1,000, Amiodarone, Atropine,
Chlorphenamine, Diazemuls, Furosemide, Morphine,
Naloxone, Ondansetron, TXA
Which is the only medication carried in a pre-filled syringe?
Adrenaline 1:10,000
What medications require reconstitution? What is used for reconstitution?
Benzylpenicillin,
Hydrocortisone, and Glucagon
Water for injection
What is the dose for Adrenaline 1:1,000 for anaphylaxis/asthma
0.5ml
What is the initial dose for Amiodarone? What should it be drawn up with?
Initial dose is 300mg which is two vials, should be drawn up with 5% glucose
What is the adult dose for furosemide? What is the YAS presentation of this drug?
The adult dose is 40mg. In YAS it comes as 50mg in 5ml, so only 4ml should be administered
How should morphine be drawn up?
Morphine is diluted in sodium chloride to 10mg/10ml, so 9ml of sodium chloride should drawn up and then 1ml of morphine.
What is the initial dose of TXA? What period should it be administered over?
The initial dose is 1g which is two vials, it should be administered over 10 minutes to avoid hypotension
What are the medications used for asthma?
Oxygen
Salbutamol
Ipratropium Bromide
Hydrocortisone
Adrenaline 1:1,000
What are the medications used for Anaphylaxis?
Adrenaline 1:1,000
Oxygen - 15L via 100% mask
IV bolus of 500-1,000ml
What anticipatory medications are used for pain
Oxycodone and morphine
What anticipatory meds are used for agitation?
Haloperidol, midazolam, diazepam
What anticipatory meds are used for Oropharyngeal secretions?
Hyoscine, hydrobromide
What anticipatory meds are used for nausea?
Haloperidol
What effects does morphine have on the CNS?
Morphine sulphate attenuates nervous impulses at the spinal cord level, it also alters the brains perception of pain.
Morphine depress the sensitivity of the respiratory centre to carbon dioxide, and also suppresses the cough centre.
Morphine sulphate also causes histamine release from mast cells, which can cause bronchoconstriction
Pharmacokinetics of morphine sulphate
Morphine is normally administered paternally because it undergoes high first pass metabolism
Morphine enters most body tissues and can cross the placenta. It is not lipophilic so does not cross the blood brain barrier
Morphine undergoes a conjugation reaction where it becomes morphine-6-glucuronide which is a potent analgesic
Excretion is mainly through urine
Explain the mechanism of action for GTN spray
organic nitrates are converted into nitrates which are then turned into nitric oxide.
Nitric oxide is a powerful vasodilator and acts by increasing the levels of cyclic GMP within cells
Elevated cGMP levels cause dephosphorylation of the myosin light chain, which causes relaxation of the smooth muscles in the blood vessel wall
What are the clinical actions of GTN
It reduces the demand for oxygen from the myocardium:
-venous dilation means venous return to the heart is decreased making the workload easier
-there is also arteriolar dilation which decreases peripheral resistance
-direct dilation of coronary vasculature improves blood flow to ischaemia improves blood flow to ischaemic areas of the myocardium
Pharmacokinetics of GTN
Nitroglycerin has a high first pass metabolism and therefore is administered orally. It is quickly absorbed sublingually and gets to work in under a minute
