MCBoM- Pharmacology drugs Flashcards
Salbutamol
For asthma, partial agonist of B2 receptors in lungs (though some action on B1 in heart
Can delay premature labour
Hemicholinium triethylcholine
Competes with choline for uptake into presynaptic varicosity at the cholinergic synapse/NMJ, so less ACh made
Vesamicol
Inhibits acetylcholine transport into vesicles at the cholinergic synapse
alpha-latrotoxin
Depletes vesicles of acetylcholine at the cholinergic synapse
Botulinum toxin
Inhibits exocytosis of ACh vesicles at the cholinergic synapse
Treats:
-blepharospasm (involuntary blinking, difficulty opening eyelids)
-focal spasticity
-spasmodic torticollis (neck move to one side)
-urinary incontinence
-improvement in appearance of wrinkles
Acetylcholine, carbachol, muscarine, bethanechol
Parasympathomimetics
Non-selective muscarinic receptor agonists
Cevimeline
Selective muscarinic 3 receptor agonist
Increases salivary and lacrimal secretion
Atropine, hyoscine
Non-selective muscarinic receptor antagonists
Pirenzepine
Selective muscarinic receptor antagonist for M1
Treats peptic ulcers
Atropine
NON SELECTIVE MUSCARINIC ANTAGONIST
- premed for anaesthesia
- treats bradycardia, inhibits M3
- antispasmodic for gut (IBS etc), inhibits M3
- counteracts anticholinesterases (organophosphate/ nerve gas poisoning)
Hyoscine
NON SELECTIVE MUSCARINIC ANTAGONIST
as with atropine +
motion sickness
Ipratropium
-short term relief from asthma, inhibits M3 in lungs
M3 receptor antagonist
Tropicamide cyclopentolate
-inhibit M3 receptors in eye causing mydriasis (dilation) and cycloplegia (no accomodation) for eye exams
Tolterodine Darifenacin
-inhibits M3 receptors in detrusor muscle to treat urinary incontinence
Histamine
Nicotinic receptor agonist
Hexamethonium
Nicotinic receptor antagonist
lowers blood pressure as ganglia block
Tubocurarine (curare)
NON DEPOLARISING NMJ BLOCKER Slow onset (5 mins+) Long duration (1-2 hours) Not used clinically- side effects are hypotension, bronchoconstriction, tachycardia, anaphylactic reactions (form histamine release)
Pancuronium, Vecuronium, Rocuronium
NON DEPOLARISING NMJ BLOCKER
Fast onset (2 mins)
30mins-1 hour duration
Used in intensive care for ventilating
Atracurium, Cisatracurium, Mivacurium
NON DEPOLARISING NMJ BLOCKER
Fast onset (2 mins)
15-30mins duration
Histamine release
Suxamethonium
ONLY DEPOLARISING NMJ BLOCKER IN USE
Fast onset (1-2 mins)
2-6 mins duration
Not broken down by acetylcholinesterase, by pseudocholinesterase instead
Muscle relaxant for tracheal intubation
Side effects:
-hyperkalaemia from K+ efflux, so heart disarrythmia and cardiac arrest
-bradycardia
-intraocular pressure rise
-prolonged paralysis with some patients (neonates, liver disease, substrates competing for cholinesterase)
-malignant hyperthermia with rare genetic condition
Edrophonium
Short acting anticholinesterase
Brief association via weak electrostatic forces
Positively charged, so attracted to negative anionic site of acetylcholinesterase, occupies and blocks from acetylcholine (competes with)
Used to diagnose myasthenia gravis (will see return of muscle strength briefly)
Neostigmine
Medium acting anticholinesterase
As with slow, but more slowly broken down by acetlycholinesterase
Used to treat myasthenia gravis
Used to reverse neuromuscular block by non-depolarising blockers
Pyridostigmine is the same, but less effect at parasympathetic synapses, so fewer side effects
Dyflos
Irreversible anticholinesterase
Forms strong covalent bond with esteratic site of acetylcholinesterase leading to depolarising block
Malathion, agricultural pesticides, nerve gases
Organophosphates.
Malathion- to kill head lice
Agricultural pesticides- to induce depolarising block, suicide
Nerve gases- in chemical warfare, induces depolarising block
Ephedrine
Displacing agent, affecting noradrenergic transmission at postganglionic sympathetic synapses
Competes with NA for uptake 1, so increased NA in synapse
Used to reverse hypotension after spinal/epidural anaesthesia
In decongestant nasal drops- vasoconstriction of mucosal blood vessels, oedema of nasal mucosa
(can - hypertension, tachycardia, reflex bradycardia)
Methyldopa
Antihypertensive (when other therapies fail)
Competes with NA for uptake 1
Converted to methylnoradrenaline
Released in exocytosis of vesicles
Activates presynaptic alpha 2 receptors which inhibit NA release, so is a false transmitter
Also activate alpha 2 receptors in CNS, so reduced sympathetic drive to CVS, lower bp
Guanethidine
Noradrenergic neurone blocker
Only used in UK for rapid control of bp in hypertensive emergencies as severe side effects
Unknown mechanism, but prevents release of NA
Adrenaline
Uses:
- resuscitation from cardiac arrest (beta 1)
- anaphylactic shock (beta)
- CPR- increases heart rate and force (beta 1)
- reverses vasodilation (alpha 1)
- causes bronchodilation (beta 2) - with local anaesthetics for local vasoconstriction to prolong drug action (alpha 2)
Phenylephrine
alpha 1 receptor agonist- to increase bp
-Treats nasal congestion (via local vasoconstriction)
-Causes mydriasis for eye examination
-Can treat acute hypotension in an emergency where other measures fail
Side effects: hypertension, tachycardia/reflex bradycardia, reduced perfusion of vital organs
Clonidine
alpha 2 receptor agonist- to decrease bp
-Treats hypertension
-Used to prevent migraine
Side effects: dry mouth, depression, sedation, bradycardia, sexual dysfunction
Isoprenaline
Mixed beta receptor agonist
To treat bradycardia or heart block (beta 1) from overdose of beta blocker
Adverse: tachycardia
Dobutamine
Mixed beta receptor agonist
For support in MI, cardiac surgery or to treat cardiogenic shock (beta 1)
Adverse: tachycardia, increase in systolic bp (alpha 1)
Dopamine
Mixed beta receptor agonist
For cardiogenic shock (beta 1)
Adverse: vasoconstriction (alpha 1), tachycardia (beta 1)
Levadopa
To treat Parkinson’s disease
Can cross blood-brain barrier where dopamine can’t
Is converted to dopamine in the CNS
Need to inhibit dopamine production peripherally also with Carbidopa or Benserazide, which cannot cross bbb
Phenoxybenzamine, phentolamine
Mixed alpha adrenoreceptor antagonists
-For short term management of hypertensive episodes in Phaeochromocytoma
Propanolol
Beta blocker (mixed beta adrenoreceptor antagonist) -For angina, arrythmias, MIs, congestive heart failure, hypertension, glaucoma, acute panic attacks
KD
Dissociation constant
Concentration of drug at which 50% of receptors are occupied
Parasymphatholytics
Parasympathomimetics
Parasymphatholytics- antagonise psns, so give SNS effects
Parasympathomimetics- mimic effects of psns
Pharmacokinetics
The way the body deals with drugs
Pharmacodynamics
The effects of the drug on the body
