pharmacology Flashcards
what trasnporter does metformin need to get across body compartments?
OCT 1
where is oct 1 expressed
liver
enterocytes
proximal tubules
why must kindye function be measured on metformin?
lactic acidosis risk due to impaired clearance
what is the mechanism of action of metformin
activates AMPK in mitochondria of hepatocytes, inhibiting ATP prodution, blocking hgo
also blocks enylate cyclase, promoting fat metabolism
increases insulin sensitivity
met formin drug target?
AMPK in hepatocyte mitochondria
side effects of metformin?
GI side effects
when is metformin most effective?
in presence of endogenous insulin
example of DPP-4 inhibitor?
sitagliptin
mechanism of DPP-4 inhibitors?
inhibit action of DPP-4 less incretin metabolism more insulin production slows digestion decreases appetite
drug target od dpp-4 inhibitors
dpp4
vascular endothelium
side effects of dpp4 inhibitors
upper rt infections
avoid in pancreatitis
no weight gain
when is dpp 4 effective
when there is b cell activity
example of sulphonylure?
gliclazide
how do sulphonylures work?
inhibit atp sensitive k channels in beta cells
this causes depolarisatino, more ca in, insulin release
side effects of sulphonylures
wieght gain
hypoglycaemia
example of sgl2 inhibitor
dapaglitozin
mechanism of sgl2 inhibitors
reversibly inhibitos sgl2 in prox tubule
reduces gluc reabsorption
side effects of sglt 2?
worsen dka
utis
less bone formation
help with weight loss and lower bp
what is the firt line treatment for diabetes?
metformin
why isnt valpropate given to women of childbearing potential?
can cause neural tube defects, lower iq and autism
what effect does the COP have on lamotrigine levels?
lowers level
COC increases UDPGA which converts it to LTG-gluc
lamotragine prescription increased if on COC
how are siezures treated in hospital?
IV benzodiazepines
how does lamotrigine work
Blocks voltage gated Na+ channels preventing Na+ influx.
Prevents depolarisation of glutamatergic neurones and reduces glutamate excitotoxicity.
drug target of lamotrigiine
voltage gated sodium channels
side effects of lamotrigine
rash, drowsiness
introduce gradually to decrease skin issues
mechanism of sodium valproate?
inhibits GABA transaminase
less breakdown of GABA
target of valproate?
GABA transaminase
side effects of valproate?
common: stomach pain and diarrhoea, drowsiness, weight gain, hair loss
less common: hepatotoxicity, teratogenicity, pancreatitis, brith defects
why does valproate increase the serum concentration of many drugs
CYP enxyme inhibitor
how does diazepam work?
upregulates gaba - increases chlorine ion infux when gaba binds
drug target of diazepam
benzo site on GABA A receptor
side effects of diazepam?
common: drowsiness, respiratory depression if IV
addiction
less common: haemolytic anaemia, jaundice
why isnt diazepam used routinely?
become tolerant
how does levetiracetam work?
inhibition of synaptic vesicle protein SV2A
prevents exocytosis
side effects of levetiracetam
dizziness
somnolence
fatigue
headache
what scoring system is used to screen depression
PHQ-9
what is the drug interaction of erythromycin and citalopram
prolong the QT interval. use of both not advised
why is there a plateau of mood improvement on ssris after a point
5-htt transporters are fully blocked
maxxed out
what does mirtazapine preferentially block at low concs
the H2 receptor
causes sleepiness
at higher doses, what does mirtazapine target?
alpha 2
5HT2
5HT3 (anti emetic)
why is the sedative effect of mirtazapine offset in higher doses?
due to increased noradrenergic transmission
what happens if venflaxine doses increase over 300 mg
increase in BP and HR
due to adrenergic effects
primary mechanism of action of sertraline, citalopram and fluoxetine?
inhibition of serotinin reuptake via the serotonin transporter
side effects of ssris?
gi effects
sexual dysfunction
anxiety
insomnia
what other targets does sertraline have?
mild inhibition of dopamine transporter
inhibits CYP2D6 at high doses so less drug metabolism