DRUGS Flashcards
what medicines are typically used to induce mydriasis?
tropicamide
phenylephrine
what is the mechanism of action of tropicamide?
- muscarinic (M3) antagonist
- stops ACh binding to M3 receptors
- stops circular muscle contraction
- stops pupil constriction
what is the mechanism of action of phenylephrine?
- alpha-adrenoceptor agonist
- binds to receptors and causes radial muscles of iris to contract
- increases pupil size
what % of tropicamide is standard?
0.5%
what % of phenylephrine is standard?
2.5%
what % is the standard does of pilocarpine?
2%
what medicines can be used to induce myopia?
pilocarpine
list 3 tricyclic ADs
desipramine
amitriptyline
clomipramine
desipramine, amitryptyline, clomipramine are all what type of antidepressant?
tricyclic
list 3 SSRIs
fluoxetine
paroxetine
flucoxamine
sertraline
citalopram
fluoxetine, paroxetine, flucoxamine, sertraline, citalopram - what type of antidepressant are these?
SSRIs
list 2 SNRIs
venlafaxine
duloxetine
venlafaxine and duloxetine are examples of what type of antidepressant?
SNRIs
what does each antidepressant block?
tricyclics and SNRIs - SERT and NAT
SSRIs block only SERT
what is the mechanism of action of propofol?
GABA agonist - increases inhibitory effect
what is the volume of distribution of propofol?
- 60L/kg
what is the MOA of isoflurane?
- reduces gap junction channel opening times
- alters tissue excitability
- induces muscle relaxation
what is the MOA of fentanyl?
- agonist of mu opioid receptor
- inhibits adenylate cyclase
- = downregulation
- hyperpolarises cell and inhibits nerve activity
what is a typical dose of fentanyl?
0.05mg/mL IV
what is the MOA of suxamethonium?
- depolarising neuromuscular blocker
- mimics ACh but not rapidly hydrolysed
wh
what is the MOA of atracurium?
- non-depolarising neuromuscular blocker
- antagonist of ACh sp. at nicotinic receptors
what is the MOA of neostigmine?
- inhibits AChE
- prolongs action of ACh
- increases muscular contraction and reverses muscle relaxants
what is hte MOA of atropine/glycopyrrate
- antagonise muscarinic receptors
- inhibit cholinergic transmission
- decreases bradycardia risk from neostigmine
what is the MOA of mannitol?
- increases blood plasma osmolarity
- increases flow of water from tissues
- decreases ICP
what is the MOA of depakote?
- folate antagonist
- blocks reuptake of GABA into glia cells
what is the MOA of paracetamol?
- selective COX2 inhibitor
- Inhibits production of prostaglandins (anti-inflammatory) and thromboxanes (anti-platelet)
what is the typical dosage of paracetamol
0.5-1g every 4-6 hours to max of 4g daily
what is the MOA of ibuprofen?
Weak COX 1 inhibitor
what is the typical dosage of ibuprofen
300-400g 3-4 times daily to max of 2.4g
what is the MOA of co-codamol
- opiod prodrug
- Mainly binds to Mu receptors
- Inhibits adenylyl cyclase
- Reduces intracellular cAMP
- Opens K channels
- Causes hyperolarisation
- Inhibits Ca2 opening
- Reduces NT release
what is the MOA of morphine?
- opioid prodrug
- Mainly binds to Mu receptors
- Inhibits adenylyl cyclase
- Reduces intracellular cAMP
- Opens K channels
- Causes hyperolarisation
- Inhibits Ca2 opening
- Reduces NT release
what is the MOA of gabapentin?
- anticonvulsant
- Increases GABA concentration by modifying Ca channels
what is gabapentin used to treat
neuropathic pain
what is the typical dosage of gabapentin
300mg OD on day 1
300mg BD on day 2
300mg x3 on day 3
what is the MOA of lidocaine?
- local anaesthetic
- Blocks Na channels
- Prevents generation of AP in pain fibres
what is the MOA of tricyclics
- Blocks reuptake of NAdr and 5HT
- Increases conc in synaptic clefts
what are the MOA of thrombolytics, like TPA
Inactivates thrombin and ADP
Cleaves plasminogen to form plasmin
Plasmin cleaves fibrin to degrade thrombi
what is the MOA of warfarin
Vit K antagonist
Vit K is a cofactor in the formation of coagulation factors VII, IX, X and thrombin
what is the MOA of aspirin
Inhibits the function of platelets in clot formation
what is the MOA of statins
Inhibit HMG-CoA reductase, the rate limiting enzyme in cholesterol synthesis
what is the MOA of SSRIs like sertraline
Selectively block serotonin reuptake transporter proteins
Increases concentration of 5HT in synapse
what is the MOA of pregabalin
- anticonvulsant that increases GABA synaptic conc
what is the MOA of benzodiazapine
- anticonvulsant
- Binds to alpha subunit of GABA-A receptor = ion channels open
- Causes influx of Cl- ions = hyperpolarisation
- Reduces anxiety
what is the MOA of SNRIs like venlafaxine
Blocks 5HT and Nadr reuptake transporter proteins
Increases conc in synaptic cleft
what is the MOA of MAOIs
Prevents reuptake of Nadr 5HT and DA
what is the MOA of L-dopa
Precursor or DA
Decarboxylated into DA after crossing BBB
Stimulates dopaminergic receptors
what is the MOA of benserazide
Peripherally-acting DOPA decarboxylase inhibitor
Reduces peripheral side effects of L-Dopa
Doesn’t cross BBB so doesn’t prevent the effects of L-dopa in brain
what is the MOA of carbidopa
dopa decarboxylase inhibitor used in combination with levodopa
what is the MOA of selegiline
Irreversible MAOB inhibitor
Increases DA in pre-synaptic neurone after reuptake
Allows more DA to be repackaged into vesicles via VMAT
what is the MOA of rasagiline
Irreversible inhibitor of MAO
what is the dosage of rasagiline
1mg daily
what is the MOA of entacapone
selective COMT inhibitor used in treatment of PD
what is the MOA of entacapone
200mg given with each dose of L-dopa
what is the MOA of risperidone
antipsychotic
Blocks D2 receptors in ventral striatum, alleviating =+ve symptoms of SZ
Blocks 5HT2 receptors in mesocortical tract - causing excess of DA
what is hte MOA of olanzipine
D1, D2, D4, 5HT and muscarinic receptor antagonist
2nd generation antipsychotic
what is the MOA of quetiapine
D1, D2, 5HT antagonist
what is the typical dosing of olanzipine
10mg daily and adjusted accord to response
what is the typical dosage of quetiapine
25mg BD for day 1
50mg BD for day 2
100mg BD for day 3
150mg BD for day 4
what is the MOA of aripiprazole
D2 partial agonist with weak 5HT agonism
what is the typical dosage of aripiprazole
10-15mg OD
what is the MOA of amisulpride
Selectivee dopamine receptor antagonist with high affinity for mesolimbic D2 and D3 receptors
what is the MOA of clozapine
D1, D2, 5HT muscarinic receptor antagonist
what is hte MOA of propofol
Strong agonist at mu opioid receptor
Inhibits adenylate cyclase
Inhibits release of nociceptive substances
what is the MOA of suxamethonium
Mimics ACh but isn’t broken down by AChE
Desensitises the NMJ
Depolarising
what is the MOA of atracurium
Blocks ACh receptors in NMJ
what is the difference between suxamethonium and atracurium
suxamethonium = depolarising
atracurium = non-depolarising
what is the MOA of isoflurane
MOA unknown
Inhaled volatile anaesthetic agent - maintains anaesthesia
what is the MOA of fentanyl
Strong agonist at mu opioid receptor
Inhibits adenylate cyclase
Inhibits release of nociceptive substances
what is the MOA of neostigmine
Blocks AChE
Increases conc. Of Ach in NMJ
Increases muscle contraction
what is the MOA of glycopyrolate
Muscle receptor antagonist
Limits parasympathetic effects caused by neostigmine eg. bradycardia
what is the difference between glycopyrolate and atropine?
atropine can cross the BBB wheres glycopyrolate cannot
what is the MOA of mannitol
osmotic diuretic
Increases solute content in proximal tubule of kidneys
Decreases fluid in body and increases plasma osmolarity
Reduces ICP