Psychiatry Flashcards
(120 cards)
Name 4 SSRIs
Fluoxetine
Sertraline
Paroxetine
Citalopram
What is the mechanism by which SSRIs work?
Presynaptic blockage of serotonin reuptake pumps.
Increases postsynaptic binding
Do NOT inhibit NA reuptake
What are the indications for SSRIs?
Depression - 1st line moderate to severe
Anxiety disorders
OCD
Bulimia nervosa (fluoxetine)
What are the SEs of SSRIs?
8 S’s
- Stress (anxiety/worry) - early
- stomach upset/bleeding - early
- Size (weight gain)
- Sexual dysfunction
- Skin rash (hypersensitivity)
- Suicidal thoughts
- Seizure threshold reduced
- Serotonin syndrome - triad of altered mental state, neuromuscular excitability, autonomic hyperactivity (hyperthermia)
What are the CIs for SSRIs?
- Mania
- Under 18s (except Fluoxetine) - reduced efficacy, increased risk of suicidal thoughts and self harm
- Epileptics - lowers seizure threshold
- Peptic ulcer disease - increased risk of bleeding
- Hepatic impairment - metabolised by liver
Why are there fewer SEs for SSRIs vs TCAs?
Because SSRIs do not block other receptors (dopamine, histamine, cholinergic, alpha-adrenergic), resulting in associated SEs
What are the drug interactions of SSRIs? (Citralopram, sertraline, fluoxetine)
- Do not combine with other serotonin increasing drugs,
- > e.g. MAOIs, TCAs - serotonin syndrome and potential overdose (convulsions, coma and cardiotoxicity- arrythmias)
- Avoid combo with drugs that prolong QT duration
- Increase plasma conc of TCA’s
How long should antidepressant drugs be taken for?
6 Months
What should be avoided wren taking anti-depressants?
- St John’s wort
- alcohol
- reduce caffeine
How are SSRIs metabolised?
Liver
What are the discontinuation Sx’s of SSRIs?
FINISH Sx
- flu like symptoms
- insomnia
- nausea
- imbalance
- sensory disturbance
- hyper-arousal
What are the symptoms of serotonin syndrome?
HARMED
- hyperthermia
- autonomic instability
- rigidity
- myoclonus
- encephalopathy
- diaphoresis
Name 4 tricyclic antidepressants
Amitriptyline
Clomipramine
Imipramine
Lofepramine
What is the mechanism by which TCAs work?
- blocks pre-synaptic 5-HT and noradrenaline re-uptake . Also blocks dopamine, histamine, alpha-adrenergic and muscarinic/cholinergic receptors.
Increases availability for post-synpatic transmission.
What are the indications for TCAs?
- 2nd Line for moderate-severe depression where SSRIs not effective
- Anxiety disorders and OCD
Tx option for neuropathic pain (not licensed for use), narcolepsy
What are the SEs for TCAs?
Brain - hallucinations, convulsions, mania
CV - arrthymias, prolongs QT and QRS (TOXIC in overdose)
Anticholinergic - dry mouth, constipation, urinary retention, blurred vision (can’t see, can’t pee, can’t shit, can’t spit)
Alpha-adrenergics - postural hypotension
Histamine - sedating, weight gain
Dopamine blockage - breast changes/gynaecomastia, sexual dysfunction, extrapyramidal Sx (PAAT: parkinson sx, akathisia, Acute dystonias, tardive dyskinesia)I
What are the CIs for TCAs?
- CV disease
- Elderly
- Mania
- Epileptics (reduces seizure threshold)
- Prostatic hypertrophy - urinary retention
- Glaucoma
- Hepatic impairment
What are the potential interactions of TCAs?
Should not be combined with MAO inhibitors/SSRIs or any other drugs that increase 5-HT/NA - serotonin syndrome
Should also not be combined with drugs that block dopamine, muscarinic, histamine or hypotensive drug
How are TCAs metabolised?
Liver
Name 3 Monoamine oxidase inhibitors
Phenelzine
Tranylcypromine
Moclobemide
What is the mechanism by which MAOIs work?
Non selective and irreversible inhibition of monoamine oxidase A and B (degrades monoamines in synaptic cleft)
What are the indications for MAOIs?
Depression (atypical/resistant - hypersomnia, overeating, anxiety)
What are the SEs of MAOIs?
Postural hypotension GI Headache/dizzy Hepatocellular necrosis (rare) Monoaminergic crisis - Hypertensive crisis (see interactions)
What are the CIs for MAOIs?
- Mania
- Hepatic dysfunction
- Phaeochromocytoma (risk of hypertensive crisis)
- Cerebrovascular disease