Transcript SSRIs & Antidepressants

SSRIs &
Antidepressants
Shanthi Antill
ST3
What we will cover…
 General
overview
 Indications for prescribing
 Choice of SSRI & side effects
 Current guidance
 Stopping & switching
 What to do if SSRIs don’t work
 Prescribing in special groups
SSRIs
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Selective serotonin reuptake inhibitors
Increase extracellular level of serotonin by
limiting reabsorption into presynaptic cell
Varying degrees of selectivity for other
monoamine transporters
Main indications include depression, anxiety +
OCD
Advantages over TCAs include:
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less sedative
fewer anticholinergic SEs
fewer cardiovascular SEs therefore safer in OD
Lesser effect on psychomotor performance
Side Effects
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Most common = GI, commonly nausea which is dose
related + often settles with use
Others include:
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Psychiatric – anxiety, panic attacks
Neurological – tremor, seizures, serotonin syndrome
CV - postural hypotension
Metabolic - SIADH, hyponatraemia
Hepatobiliary – abnormal LFTs
MSK - myalgia, arthralgia
Urological - urinary retention
Reproductive - sexual dysfunction
Skin - pruritus, rash,sweating, angioedema
GI - nausea,vomiting, diarrhoea,dry mouth,GI bleeding
Other – dizziness,insomnia, drowsiness, fatigue
Type
Examples
SSRI – Selective serotonin reuptake
inhibitor
Citalopram
Escitalopram
Paroxetine
Fluoxetine
Sertraline
Fluvoxamine
SNRI – Selective noradrenaline
reuptake inhibitors
Duloxetine
Venlafaxine
Desvenlafaxine
NaSSA - Noradrenergic and specific
serotonergic antidepressants
Mirtazepine
SARI – Serotonin antagonist and
reuptake inhibitor
Trazodone
TCA – tricyclic antidepressants
Amitriptyline
Dosulepin
Doxepin
Imipramine
Points to be aware of…
 Paroxetine
– more weight gain, higher
rates of sexual dysfunction, more
dangerous in withdrawal
 Sertraline – higher rate of diarrhoea
 Citalopram/escitalopram – prolong QT
interval so consider other medications
 Fluoxetine – longer half-life compared to
rest of SSRI
 Mirtazepine – helps sleep, increases
appetite for carbs so often causes weight
gain (can be helpful with certain patients)
Choice of treatment (1)
 Choice
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depends on:
Adverse effect profiles
Patient preference
Previous experience of treatment
Likelihood to cause discontinuation
symptoms
Safety in overdose
Choice of treatment (2)
 Cipriani
et al, 2009
 Compared 12 new generation
antidepressants
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Systematic review of 117 RCTs, 25928
participants from 1991-2007
 Favoured
escitalopram and sertraline with
regards to efficacy + favorability
 Sertraline as best choice when starting
treatment for moderate – severe
depression in adults
NICE guidance…
 Depression
– all SSRIs are licensed.
Paroxetine only for major depression
 Panic disorder – citalopram, escitalopram,
paroxetine
 Social anxiety – escitalopram, paroxetine
 OCD – fluoxetine, fluvoxamine,
paroxetine, sertraline
 PTSD – paroxetine, sertraline (only in
females)
 GAD - paroxetine
Starting SSRIs
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Before starting ensure patients are aware that they
may take a few weeks to work
Review 1-2 weeks after starting treatment.
A trial of at least 4-8 weeks (6 weeks in older
patients) should be given before deciding to
discontinue/change an agent
If partial response, allow another 2 weeks to
decide if effective or not
Little evidence to support use of dose escalation in
patients who do not respond to standard doses
After remission of symptoms, continue for at least
4-6 months (12 months in the older patient)
Switching treatment
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clear guidance on switching
antidepressants
 Maudsley Prescribing guidelines offers
table of advice.
 Note long half-life (1 week) of fluoxetine
affects regime
 MIMS/GP notebook have good online
reference tables when looking to switch
Stopping treatment
 Patients
should be advised not to stop
treatment suddenly or omit doses.
 Drug and Therapeutics Bulletin advises:
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after a 'standard' 6-8 months treatment it is
recommended that treatment should be
tapered off over a 6-8 week period
if the patient has been on long-term
maintenance therapy then an even more
gradual tapering e.g. by 1/4 of the
treatment dose every 4-6 weeks.
if a course has lasted < 8 weeks then
discontinuation over 1-2 weeks is safe
Discontinuation symptoms
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Review patients who are stopping/weaning
SSRIs regularly
If suffering with any symptoms, consider
increasing dose & tapering even more
cautiously
Generally begin within 24-72 hours of stopping
and last approximately 1-2 weeks
Most commonly nausea, dizziness, headache
and lethargy
Other symptoms include paraesthesia, 'shocklike' sensations, anxiety, tremor, balance
problems, nightmares, insomnia and sweating
What if treatment doesn’t work?
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Consider trying different SSRI
Can try combining 2 antidepressants
Venlafaxine & duloxetine thought to be good in
treatment resistant cases
Can also try older agents depending on
experience
 Amitriptyline/nortriptyline
 Dosulepin
If still ineffective or unsure, refer secondary care
 Lithium augmention
 Antipsychotics
Prescribing in certain groups
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Children/young people
 NICE state only after specialist review
 Fluoxetine 10mg first line, increased to 20mg if
needed after 1 week
 2nd line – citalopram or sertraline
Post stroke depression – sertraline or mirtazepine
Chronic disease – consider sertraline as lower
propensity for interactions with other medications
Elderly – consider risk of falls with SSRIs/drug
interactions. Sertraline or citalopram good choices
if required
Diabetes – diabetes double odds of co-morbid
depression. Most data suggests fluoxetine most
effective