PPT - DEPRESSION + ANXIETY Flashcards
What are examples of SSRIs?
Citalopram
Escitalopram
Fluoxetine
Sertraline
Paroxetine
Dapxetine
Dapoxetine
Fluvoxamine
Vortioxetine
What are the indications for SSRIs?
Depression
GAD
OCD
Panic disrder
Severe phobic disorders
Bulimia
PTSD
What are contraindications for all SSRIs?
Poorly controlled epilepsy
Manic phase of bipolar disorder
What are additional contraindications for citalopram and escitalopram?
Known QR interval prolongation
Concurrent use of drugs known to prolong QT interval
Whats an additional contraindication of sertraline?
Severe hepatic impairment
Whats the moa of SSRIs?
They block the serotonin transporter which prevents serotonins re uptake from the simpatico space, therefore increasing its availability
What are examples of monoamine uptake inhibitorS?
TCAs
SSRIs
SNRIs
Outline the chronic adaptive changes seen with SSRIs?
On acute administration, one would expect inhibition of serotonin reuptake to increase the level of 5-HT at the synapse. However, the increase has been observed to be less than expected.
This is because increased activation of 5-HT1A receptors on the soma and dendrites of raphe neurons inhibits these neurons and thus reduces 5-HT release, thus cancelling out to some extent the effect of inhibiting reuptake into the terminals.
On prolonged drug treatment, the elevated level of 5-HT in the somatodendritic region desensitises the 5-HT1A receptors, reducing their inhibitory effect on 5-HT release from the nerve terminals. The need to desensitise somatodendritic 5-HT1A receptors could thus explain in part the slow onset of antidepressant action of 5-HT uptake inhibitors.
Why are SSRIs first-line for depression treatment?
Less likely than other antidepressants to cause anticholinergic SE and less dangerous in overdose
Do not cause ‘cheese reactions’ like MAOIs
Less sedative
Less cardiotoxic than TCAs
Whats the half life of SSRIs?
Most have half lives of 18-24 hours
Fluoxetine is longer acting with a half life of 24-96 hours
Which SSRIs should not be given concurrently with TCAs and why?
Fluoxetine, fluvoxamine and paroxetine
They may increase TCA plasma levels and cause toxicity
What is 5HT1A?
A subtype of serotonin receptor located in presynaptic and postsynaptic regions
Upon activation they inhibit firing of 5HT neurons
What are some cardiac adverse effects of SSRIs?
Whats the most widely used SSRI for CVD patients?
Sertraline - free of Cardiotoxicity
What are possible adverse effects of SSRIs?
Most common - GI disturbance at start of treatment , anxiety and agitation early on, loss of appetite and weight loss, insomnia, sweating, sexual dysfunction
Cardiac - palpitations, QT prolongation, rarely tachycardia
GI - reduced appetite, d+v+n, dry mouth, abdominal pain, constipation, altered taste, weight changes
CNS - headache, dizziness, drowsiness, tinnitus, paraesthesia, tremor, sleep disorders, visual impairment, convulsions and movement disorders
Psychiatric - insomnia, agitation, confusion, reduced concentration, anxiety, memory loss, depersonalisation
Skin - rash, hyperhidrosis, Alopecia, pruritus, photosensitivity reaction
Other - haemorrhage, menstrual cycle irregularities, sexual dysfunction, myalgia, urinary disorders, hyponatraemia, SIADH
Serotonin syndrome
What are the signs of serotonin syndrome?
Confusion, delirium, shivering, tachycardia, anxiety, agitation, sweating, major changes in blood pressure, diarrhoea, and muscle twitching
Severe - seizures, arrhythmias and unconcious
When may serotonin syndrome occur?
when combinations of serotonergic antidepressants are prescribed; most severe cases of serotonin syndrome involve an MAOI (including moclobemide) and an SSRI.
Remember st Johns wort can raise levels of serotonin when combined with SSRI
Ecstacy and amphetamines also increase the risk
What are signs of hyponatraemia?
Dizziness, drowsiness, confusion, nausea, muscle cramps, or seizures, reduced appetite
Severe - disorientation, agitation, psychosis and fits, coma
What are side effects specific to citalopram or escitalopram?
Torsades de pointes
What are some possible drug interactions associated with SSRIs?
Antiepileptics
Antidiabetic drugs
Aspirin, NSAIDs, anticoagulants, antiplatelets
Carbamazepine
Cocaine
Grapefruit juice
HIV protease inhibitors
Lithium
MAOIs
SNRIs
Tamoxifen
Other sedative drugs
Opioids, St. John’s wort, Triptans
Drugs which can cause QT interval prolongation
Drugs which are associated with hyponatraemia
What should be prescribed if a patient is taking SSRIs and NSAIDs and why?
A proton pump inhibitor due to the increased risk of GI bleeding
What are the most favoured SSRIs?
Sertraline and escitalopram
What have NICE suggested doing when choosing SSRI for people who also have a chronic physical health problem?
Using citalopram or sertraline as they have a lower propensity for interaction
How should we treat depression when a pt is on warfarin, heparin or aspirin?
Use mirtazapine and avoid SSRI
SSRIs inhibit its metabolism so increase the risk of bleeding