Psycho-Pharmacology Flashcards
list the indications for antidepressants
- Unipolar and bipolar depression
- Organic mood disorders
- Schizoaffective disorder
- Anxiety disorders including OCD
- Panic
- Social phobia
- PTSD
- Premenstrual dysphoric disorder
- Impulsivity associated with personality disorders
on the 1st, 2nd and 3rd episode of depression how long would you continue antidepressants?
1st - 6months - year
2nd - 2 years
3rd - lifelong
what side effects may TCAs have?
antihistiminic
anticholinergic
antiadrenergic
why are TCAs only dispensed in small amounts?
lethal in OD of even just 1 week supply
what ECG change can TCAs cause?
QT lengthening
what are tertiary TCAs, why may they have more side effects?
tertiary amine side chains
cross react with other types of receptors
give 4 examples of tertiary TCAs
imipramine, amitriptyline, doxepin and clomipramine
name two active metabolites of tertiary TCAs
desipramine and nortriptyline
what are secondary TCAs?
often metabolites of tertiary amines that primarily block noradrenaline
name two secondary TCAs
desipramine and nortriptyline
compared with tertiary TCAs what are the SEs of secondary TCAs like?
same but generally less severe
describe the MoA of MAOIs
MAOIs bind irreversible to monoamine oxidase thereby preventing the inactivation of amines such as
norepinephrine, dopamine and serotonin leading to increased synaptic levels.
what are MAOIs useful for treating?
resistant depression
list the side effects of MAOIs
orthostatic hypotension, weight gain, dry mouth,
sedation, sexual dysfunction and sleep disturbance.
what is the Cheese Reaction?
Hypertensive crisis can develop when MAOIs are
taken with tyramine-rich foods or sympathomimetics
how may serotonin syndrome develop?
if an MAOI is taken alongside medications that increase serotonin or have sympathomimetic actions
symptoms of serotonin syndrome
abdo pain, diarrhoea,
sweats, tachycardia, HTN, myoclonus, irritability, delirium
what can serotonin syndrome lead to?
hyperpyrexia, cardiovascular
shock and death
how long must you wait when switching from an SSRI to an MAOI (excluding fluoxetine)?
2 weeks
how long must you wait when switching from fluoxetine to an MAOI and why?
5 weeks - long half life
what do SSRIs do?
block presynaptic serotonin reuptake
what are SSRIs used for?
anxiety and depression
what are the most common SEs of SSRIs?
GI upset, sexual dysfunction (30% +), anxiety,
restlessness, nervousness, insomnia, fatigue or sedation, dizziness.
what may stopping SSRIs cause? what is this?
Discontinuation syndrome results in agitation, nausea, disequilibrium and dysphoria.
when starting SSRI patients may experience symptoms. what are these and how long does it normally last?
Activation syndrome results from an increased serotonin that can be depressing for the patient.
Nausea, increased anxiety, panic and agitation are common symptoms. These typically last 2-10 days
so always warn the patient.
activation and discontinuation syndrome are both more common with what kind of SSRIs? what may you give instead?
short half life drugs
fluoxetine
give examples of SSRIs
paroxetine sertaline fluoxetine (prozac) citalopram escitalopram fluvaxamine
discuss paraxetine
This drug has a short half-life with no active metabolites. This means there is no build-up which is good
if hypomania develops. It has sedating properties (dose taken at night) and offers good initial relief
from anxiety and insomnia. likely to cause discontinuation syndrome
what side effects are associated with paroxetine?
sedation
weight gain
anticholinergic
discuss sertraline
Sertraline has very weak interactions with P450 enzymes, only slightly with CYP2D6. It has a short halflife
with lower build-up of metabolites. It is less sedating when compared to paroxetine. For max
absorption it is necessary to take on a full stomach which may be problematic in some patients. There
is also an increased number of GI adverse drug reactions.
discuss fluoxetine
Fluoxetine has a long half-life and as a result there is decreased incidence of discontinuation
syndromes. It is good for patients with medication noncompliance issues. Initially activating so may
provide increased energy. Secondary to its long half-life, you can give one 20mg tablet to taper
someone off an SSRI to try and prevent SSRI discontinuation syndrome.
Its long half-life and active metabolites may result in build up, so it is not a good choice in patients
with hepatic illness. It has significant interaction with P450, so it may not be a good choice in patients
already on a number of different medication. Initial activation may cause an increase in anxiety and
insomnia. It is more likely to induce mania than some of the other SSRIs.
compared to other SSRIs fluoxetine is more likely to induce what?
mania
discuss citalopram
Citalopram has a low inhibition of P450 enzymes and as such there are fewer drug-drug interactions.
Its half-life is intermediate. Doses >40mg/day are not recommended as there is dose-dependent QT
prolongation with doses between 10 and 30 mg. it can be sedating as it has mild antagonism at H1
receptors. It has some GI SEs, but these are less than sertraline.
discuss escitalopram
This is the s-enantiomer of the racemic derivative citalopram. Escitalopram has a low overall inhibition
of P450s and as such there are fewer drug-drug interactions. Its half-life is intermediate. Due to acute
response and remission it is more effective than citalopram. There is dose dependent QT interval
prolongation with doses of 10-30mg daily. Nausea and headache is associated.
discuss fluvoxamine
This has the shortest half-life and has been found to possess some analgesic properties.
what side effects are associated with fluvoxamine?
GI distress
headaches
sedation
weakness
fluvoxamine is a strong inhibitor of what enzymes?
CYP1A2
CYP2C19
discuss SNRIs
These drugs inhibit both serotonin and noradrenergic reuptake like the TCAs but without the
antihistamine, antiadrenergic and anticholinergic SEs.
what are SNRIs used for?
depression
anxiety
neuropathic pain
give 2 examples of SNRIs
venlafaxine
duloxetine
discuss venlafaxine
There is minimal drug interactions and almost no P450 activity. It has a short half-life and fast renal
clearance avoids build up. Therefore, this is a good drug for geriatric populations. However, it can
cause a 10-15 mmHg dose dependent increase in diastolic BP
what SE are associated with venlafaxine
significant nausea
bad discontinuation syndrome
QT prolongation
sexual