antidepressants Flashcards
what are they used to treat?
depression, anxiety, panic disorder, obsessive-compulsive disorder, post-traumatic stress disorder, and phobic states such as social anxiety disorderwh
what is most favourable now?
SSRIs due to lower s/e profile and lower risk of toxicity
how do SSRIs work?
SSRIs selectively inhibit serotonin reuptake, increasing its availability and enhancing mood regulation.
when are SSRIs used?
SSRIs are first line for medical management of depression, generalised anxiety disorder (GAD), panic disorder, obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD), and phobic states such as social anxiety disorder.
when should SSRIs be used with caution?
Should be omitted in mania
Should be used with caution in children and adolescents
Should be avoided in patients taking warfarin, due to increased risk of bleeding
what SSRI best for pts with ischameic heart disease>?
sertraline
what are s/e of SSRIs?
GI upset
Anxiety and agitation
QT interval prolongation (especially associated with citalopram)
Sexual dysfunction
Hyponatraemia
Gastric Ulcer
how should you monitor SSRIs in young people?
In people aged 18-25 there is an increased risk of impulsivity and suicidal risk upon commencing antidepressant medication and so they should have a follow-up appointment arranged after one week to monitor progress. Initial reviews can otherwise be arranged 2-4 weeks after starting medication in patients >25.
how long should SSRIs be used?
Continuation of antidepressants for at least six months post-remission is recommended to mitigate relapse risk. Tapering should be done gradually over a four-week period when discontinuing antidepressants.
what is serotonin syndrome?
potentially life-threatening condition linked with increased serotoninergic activity in the central nervous system.
when does serotonin syndrome present?
within the first few months of starting a Selective Serotonin Reuptake Inhibitor (SSRI) or due to drug interactions (SSRI + tramadol).
what is serotonin syndrome characterised by?
mental status changes, autonomic hyperactivity, and neuromuscular abnormalities
how do SNRIs work?
SNRIs work by increasing serotonin and norepinephrine levels, improving mood and anxiety.
when are SNRIs indicated?
when are SNRIs contraindicated?
Contraindicated in those with a history of heart disease and high blood pressure
s/e of SNRIs?
Nausea
Insomnia
Increased heart rate
Agitation
what are NaSSA?
Noradrenergic and specific serotonergic antidepressant
how do NaSSA work?
NaSSAs such as mirtazepine also work by modulating norepinephrine and serotonin levels in the brain.
when are NaSSA indicated?
Mirtazepine is a second line choice of medication for management of depression, though may be preferred if in particular there are concerns over weight loss, as one of it’s side effects is increased appetite. It may also be preferred if there are issues with getting to sleep as it is a light sedative and so it is usually taken in the evening.
s/e of NaSSA?
Sedation
Increased appetite
Weight gain
Constipation/diarrhoea
what are tricyclic antidepressants MOA?
Tricyclic and related antidepressants block the re-uptake of both serotonin and noradrenaline, and examples include amitriptyline, clomipramine and imipramine. They are also antimuscarinic
indications to use tricyclics?
They are another example of second line choices for treatment of depression, and are sometimes. used in the management of panic and other anxiety disorders.
when are tricyclics contraindicated?
Contraindicated in those with previous heart disease
what can tricyclics exacerbate?
Can exacerbate schizophrenia
May exacerbate long QT syndrome
when should tricyclics use with caution?
pregnancy and breastfeeding
May alter blood sugar in T1 and T2 DM
May precipitate urinary retention, so avoid in men with enlarged prostates
avoid in those on other CP450 medications or those with liver damage
s/e of tricyclics?
anticholinergic effects:
Urinary retention
Drowsiness
Blurred vision
Constipation
Dry mouth
what are key signs/symptoms of tricyclic toxicity?
drowsiness, confusion, arrhythmias, seizures, vomiting, headache, flushing, and dilated pupils
how do you ix tricyclic toxicity?
blood tests (FBC, UE, CRP, LFTs), Venous Blood Gas, and an ECG to check for QT interval prolongation
management of tricyclic toxicity?
supportive care based on patient symptoms, with considerations for activated charcoal within 2-4 hours of the overdose and intensive care review in severe cases.
what are MAO-Is?
Monoamine oxidase inhibitors
what are MOA of MAOIs?
Monoamine oxidase (MAO) normally metabolises serotonin and noradrenaline in the presynaptic cell. MAO inhibitors inhibit monoamine oxidase which leads to an elevation in brain levels of catecholamines and serotonin. It has a similar structure to amphetamine so this also affects the uptake and release of dopamine, noradrenaline, and serotonin.
examples of MAOIs?
Examples include moclobemide (MAO-B inhibitor), phenelzine (MAO-A inhibitor).
indications for MAOIs?
They were historically used to treat depression but are used less frequently now.
when should MAOIs be used with caution?
Cerebrovascular disease
Manic phase of bipolar disorder
Phaeochromocytoma
Severe cardiovascular disease
s/e of MAOI?
Hypertensive reactions (‘cheese reaction’) with tyramine-containing foods (so patients need to avoid pickled herring, Bovril, Oxo, Marmite, cheese, salami).
Should also avoid broad bean pods as these contain dopa.
