pharmacology Flashcards

1
Q

which drugs most effectively diffuse across the blood brain barrier?

A

lipophillic / hydrophobic

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2
Q

give examples of monoamines

A

dopamine
noradrenaline
5-HT (serotonin)

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3
Q

which antidepressant should be avoided in a 57y/o man with ischaemia heart disease who is now depressed following an MI 2 months ago?

A

imipramine - tricyclic -> cardiotoxic

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4
Q

which mood stabiliser requires therapeutic drug monitoring?

A

lithium

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5
Q

effect of dehydration on lithium levels

A

increase lithium levels

increases absorption of sodium pulls lithium as well (no discrimmination)

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6
Q

which side effects would suggest llithium levels in the toxic range?

A

 Vomiting, diarrhoea
 Ataxia, coarse tremor
 Drowsiness, altered conscious level
 Convulsions coma

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7
Q

which mood stabiliser is absolutely to be avoided in someone hoping to get pregnant?

A

valproic acid - sodium valporate

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8
Q

depression results from a functional deficit in which transmitters?

A

monoamine
in particular serotonin (5-HT) + noradrenaline

drugs that deplete stores of monoamines (reserpine) can induce low mood

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9
Q

examples of monoamine oxidase inhibitors

A

phenelzine, moclovemide
-> reserved for 4th line

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10
Q

side effects of monoamine oxidase inhibitors

A

“cheese reaction” - hypertensive crisis from tyramine containing foods - cheese, soy sauce (avoid)

insomnia
decrease metabolism of other drugs
postural hypotension
peripheral oedema

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11
Q

examples of tricyclics

A

imipramine, dosulepin, amitriptyline, lofepramine

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12
Q

MoA of tricyclics

A

block reuptake of monoamines (mainly noradrenaline + 5-HT) into presynaptic terminals

(non-selective)

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13
Q

side effects of tricyclics

A

cardiotoxic in overdose
CV - postural hypotension, tachycardia, arrhythmias

anticholinergic - blurred vision, dry mouth, constipation, urinary retention
weight gain
sedation

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14
Q

examples of SSRIs

A

fluoxetine, citalopram, sertraline, paroxetine

(selective serotonin reuptake inhibitors)

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15
Q

MoA of SSRIs

A

selectively inhibit reuptke of serotonin (5-HT) from synaptic celft

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16
Q

side effects of SSRIs

A

nausea, headache
worsened headache
transient increase in self harm
suicidal ideation in <25yrs
sweating/vivid dreams
sexual dysfunction

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17
Q

examples of noradrenaline reuptake inhibitors

A

reboxetine
desipramine
protriptyline

18
Q

examples of SSNRIs

A

duloxetine, venlafaxine

(selective serotonin noradrenaline (dual) reuptake inhibitors)

19
Q

MoA of SSNRIs

A

block reuptake of monoamines (BOTH 5-HT + norad) into presynaptic terminals

20
Q

side effects of SSNRIs

A

similar to SSRIs
nausea, headache

21
Q

bupropion drug class

A

dopamine uptake inhibitor

22
Q

which 2 antidepressants cause particularly worse withdrawal symptoms

A

venlafaxine (SSNRI)
paroxetine (SSRI)

23
Q

MoA of lithium

A

may block phosphatidylinositol og inhibit glycogen synthase 3-betas or modulate NO signalling

liver does nothing to lithium, it is RENALLY excreted

24
Q

lithium monitoring

A

12hr post dose bloods

target range = 0.4-1mmol/l with the higher end being associated with better response

25
Q

lithium side effects

A

dry mouth/strange tase
hypothyroidism
nephrogenic diabetes insipidus
reduced renal

26
Q

lithium side effects

A

dry mouth/strange tase
hypothyroidism
nephrogenic diabetes insipidus
reduced renalnction

polydispsia, polyuria
tremor
weight gain

27
Q

lithium toxicity features

A

D+V
ataxia, coarse tremor
drowsiness, altered conscious level
convulsions coma

28
Q

anticonvulsants as mood stabilisers

A

Examples = valproic acid, lamotrigine, carbamazepine

Side effects
- Valproate + carbamazepine – drowsiness, ataxia, CV effects, induces liver enzymes
- Valproate – teratogenicity (neural tube defects)
- Lamotrigine – small risk of stevens-Johnson syndrome

29
Q

antipsychotics as mood stabilisers

A

Examples = quetiapine, aripiprazole, olanzapine, lurasidone

MoA – dopamine antagonism + 5-HT antagonism

Side effects
- Sedation, weight gain, metabolic syndrome
- Extra-pyramidal side effects - aripiprazole

30
Q

antipsychotics as mood stabilisers

A

Examples = quetiapine, aripiprazole, olanzapine, lurasidone

MoA – dopamine antagonism + 5-HT antagonism

Side effects
- Sedation, weight gain, metabolic syndrome
- Extra-pyramidal side effects - aripiprazole

31
Q

GABA receptors

A

main inhibitory transmitter in brain

reduces activity of neurons in amygdala + CSTC circuit

benzoodiazepines enhance GABA action

32
Q

receptor target of benzodiazepines

A

GABA-A

  • also target for barbituates + alcohol
33
Q

examples of benzodiazepines

A

lorazepam
diazepam - valium
chlordiazepoxide
loprazolam

34
Q

pathophysio of benzodiazepines

A

GABA-A receptor is an inhibitory inotropic receptor

In the presence of GABA the ion channel allows chloride ion (negative) influx
o Resulting in membrane hyperpolarisation – pushes membrane potential further from zero (more negative) so less likely for neuron to fire an action potential

Benzodiazepines increase the activity at the GABA via allosteric modulation
o Less likely to fire action potential
o Inhibit neurons involved with anxiety and arousal
(inhibitory postsynaptic potential)

35
Q

effect of agonist at the benzodiazepine site

A

relaxation + anticonvulsant effects

36
Q

effect of antagonist at the benzodiazepine site

A

anxiety + pro-convulsant

37
Q

effect of benzodiazepines

A

reduce axiety + agression
hypnosis/sedation
muscle relaxation
anticonvulsant effect
anterograde amnesia

38
Q

benzodiazepines have rapid action, well tolerated + efficious but have problems, esp if used over 2 week - what are they problems?

A
  • sedation + coordination impairment
  • withdrawals, dependency + abuse
  • paradoxical aggression
  • alcohol interaction
  • can worsen co-morbid depression
39
Q

effect of rapid withdrawal of benzodiazepines

A

confusion
psychosis
convulsions
hypertension
tremor

40
Q

neuroadaptation in chronic treatment of benzodiazepines

A

decreases response to GABA
withdrawal result in anxiety/convulsions possibly due to decrease density of benzodiazepine receptors

41
Q

how to with draw benzodiazepines

A
  1. Transfer patient to equivalent daily dose of diazepam/chlordiazepoxide – preferably taken at night
  2. Reduce dose every 2-3weeks in steps of 2 or 2.5mg
    a. If withdrawal symptoms occur, maintain this dose until symptoms improve
  3. Reduce dose further, if necessary, in smaller steps – better to reduce too slow than too quick
  4. Stop completely – time needed for withdrawal can vary from about 4 weeks to a year
41
Q

how to with draw benzodiazepines

A
  1. Transfer patient to equivalent daily dose of diazepam/chlordiazepoxide – preferably taken at night
  2. Reduce dose every 2-3weeks in steps of 2 or 2.5mg
    a. If withdrawal symptoms occur, maintain this dose until symptoms improve
  3. Reduce dose further, if necessary, in smaller steps – better to reduce too slow than too quick
  4. Stop completely – time needed for withdrawal can vary from about 4 weeks to a year