Psychopharmacology Flashcards
What is important to establish before prescribing a medication for psychiatric problem?
Diagnosis
target symptoms - monitor therapy response
How to select the agent and dose
acceptable side effect profile
lowest effective dose
been on medication before which worked
PMH
Indications for anti-depressants
unipolar and bipolar depression
organic mood disorders
schizoaffective disorder
anxiety disorders - OCD, panic, social phobia, PTSD
How long is the delay after therapeutic dose is achieved and symptoms improving?
3-6 weeks
If no improvement after 2 months of adequate dose what should be done?
switch to another antidepressant or augment with another agent
Classifications of antidepressants
TCAs MAOIs SSRIs SNRIs Novel antidepressants
3 potentially unacceptable side effect profile of TCAs
anticholinergic
antihistaminic
antiandrenergic
Caution with prescribing even a weeks dose of TCAs
lethal in overdose
can cause QT lengthening
Why do TCAs have the 3 side effect profile?
tertiary side chains cross react with other types of receptors
antihistaminic side effects
sedation and weight gain
anticholinergic side effects
dry mouth
dry eyes
constipation
memory deficits and delirium
Anti adrenergic side effects
orthostatic hypotension
sedation
sexual dysfunction
tertiary TCAs receptors
predominantly serotonin
Examples of tertiary TCAs
imipramine
amitriptyline
clomipramine
Where do secondary TCAs arise from?
metabolites of tertiary TCAs
primary action of secondary TCAs
block noradrenaline
Examples of secondary TCAs
desipramine
nortriptyline
How do MAOIs work?
bind irreversibly, preventing inactivation of amines eg Norepinephrine, dopamine and serotonin
What are MAOI’s very effective for?
depression
Side effects of MAOIs
orthostatic hypotension weight gain dry mouth sedation sexual dysfunction sleep disturbance
Hypertensive crisis occurs with which meds and when?
MAOIs
taken with tyramine rich foods or sympathomimetics
cheese reaction
Serotonin syndrome occurs with which meds and when?
MAOI and meds that increase serotonin or sympathomimetics
Serotonin syndrome symptoms
abdominal pain diarrhoea sweats tachycardia HTN myoclonus irritability delirium death
How to avoid serotonin syndrome
wait 2 weeks before SSRI –> MAOI (fluoxetine is 5 weeks)
How do SSRIs work?
block presynaptic serotonin reuptake
Side effects of SSRIs
GI upset sexual dysfunction * anxiety restlessness nervousness insomnia fatigue or sedation dizziness
What do SSRIs treat?
anxiety and depression
Discontinuation syndrome of SSRIs
agitation
nausea
dysphoria
Name some SSRIs
paroxetine sertraline fluoxetine citalopram escitalopram fluvoxamine
How o SNRIs work?
block both serotonin and noradrenergic reuptake like TCAs
Positives of SNRIs compared to TCAs
no anti cholinergic, histaminic or adrenergic side effects
SNRIs uses
depression
anxiety
neuropathic pain
Examples of SNRIs
venlafaxine
duloxetine
Mirtazapine
5HT2 and 5HT3 receptor antagonist
Buproprion
good as augmenting agent
How to combat treatment resistance with antidepressants
combo eg SSRI/SNRI with mirtazapine
adjunctive with lithium
adjunctive with atypical antipsychotic eg olanzapine
ECT
Indications for mood stabilisers
bipolar
cyclothymia
schizoaffective
Classes of mood stabilisers
lithium
anticonvulsants
antipsychotics
Only medication to reduce suicide rate
lithium
Factors predicting positive response to lithium
prior long term response of family member good response
classic pure mania
mania followed by depression
before starting lithium
U+E, TSH
pregnancy test - ebsteins
monitoring lithium
TSH and creatinine
Goal blood level for lithium
0.6-1.2
Lithium side effects
GI distress - low appetite, vomiting, diarrhoea
thyroid abnormalities
polyuria/polydipsia
hair loss and acne
Symptoms of lithium toxicity
vomit, diarrhoea, convulsions, renal failure, blurred vision, syncope
Valproic acid compared to lithium
as effective in mania prophylaxis but not depression prophylaxis
better tolerated
Factors predicting positive response to valproic acid
rapid cycling patient - F
co morbid substance issue
mixed patients
comorbid anxiety disorder
Before starting valproic acid
LFT
pregnancy test
FBC
folic acid supplement in women
monitoring valproic acid
LFT and CBC
Goal blood level valproic acid
50-125
Valproic acid side effects
thrombocytopenia
nausea, weight gain
sedation, tremor
NTD
What is carbamazepine first line for?
acute mania and mania prophylaxis
Who is carbamazepine indicated for?
rapid cyclers
mixed patients
Before starting carbamazepine
LFT, FBC, ECG
Monitoring carbamazepine
CBC and LFT
Why must you check and adjust carbamazepine levels at a month?
induces own metabolism
carbamazepine side effects
RASH
nausea, vomit, sedation, ataxia, water retention, drug-drug interactions
Lamotrigine side effects
N&V, sedation, TEN, SJS - stop if any rash
blood dyscriasis
What does valproic acid do to lamotrigine?
increases/doubles levels
Indication for antipsychotics
schizophrenia
schizoaffective
bipolar - mood stabilisation/psychotic
psychotic depression
4 dopamine pathways in brain
mesocortical
mesolimbic
nigrostriatal
tuberoinfindibular
mesocortical
brain stem to cortex
negative symptoms
too little dopamine
mesolimbic
dopaminergic cell bodies in brainstem to limbic system
positive symptoms
too much dopamine
nigrostriatal
dopaminergic cell bodies in substantia nigra to basal ganglia
movement regulation
Dopamine effect on Ach
suppression
Dopamine hypoactivity
parkinsonian movements
Tuberoinfindibular
hypothalamus to ant.pit.
Dopamine effect on prolactin
inhibits release
Blocking dopamine in tuberoinfindibular pathway
hyperprolactinaemia
gynaecomastia, galactorrhoea
Typical antipsychotics class
D2 dopamine receptor antagonists
High potency typical antipsychotics
bind with high affinity
extrapyramidal side effects
Low potency typical antipsychotics
less affinity for 2
interact with non dopaminergic receptors
anticholinergic effects
How atypical antipsychotics work
serotonin-dopamine 2 antagonists
Why are atypical antipsychotics atypical?
affect dopamine and serotonin neurotransmission in 4 key brain dopamine pathways
Examples of atypical antipsychotics
risperidone olanzapine Seroquel apiprazole clozapine
What is clozapine associated with?
agranulocytosis - weekly blood draws
Antipsychotic adverse effects
tardive dyskinesia
neuroleptic malignant syndrome
EPS
Agents for EPS
anticholinergics
dopamine facilitators
beta blockers
Atypical antipsychotics before starting
fasting lipid profile
fasting blood sugar
LFT
CBC
Anxiolytic use
panic disorder
GAD
substance related
insomnia
Using anxiolytics to treat anxiety
used with SSRI or SNRI
Anxiolytics
BZD
buspirone
BZD side effects
somnolence amnesia cognitive deficits disinhibition tolerance dependence
