Psychiatric Medications Flashcards
What are some antidepressant classifications?
SSRI’s ; selective serotonin re-uptake inhibitors
Tricyclic antidepressants
Monamine Oxidase inhibitors
Serotonin/Noradrenaline Reuptake Inhibitors (SNRIs)
Novel antidepressants
What are indications for antidepressants?
Unipolar and bipolar depression
Organic mood disorders
Schizoaffective disorder
Anxiety disorders; OCD, panic, social phobia, PTDS
Describe TCA side effects
Very effective but potentially unacceptable side effect profile
- antihistaminic (sedation and weight gain)
- anticholinergic (dry mouth, eyes, constipation, memory deficits)
- antiadrenergic (orthostatic hypotension, sedation, sexual dysfunction)
Lethal in overdose
Can cause QT lengthening
Describe tertiary TCAs
Have tertiary amine side chains
Side chains are prone to cross react with other types of receptors
Act predominantly on serotonin receptors
Examples; imipramine, amitriptyline, doxepin, clomipramine
Have active metabolites including desipramine, nortriptyline
Describe secondary TCAs
Are often metabolites of tertiary amines
Primarily block noradrenaline
Side effects are same as tertiary TCAs but generally less severe
Examples; desipramine, nortryptiline
Describe monoamine oxidase inhibitors (MAOIs) method of action
Bind irreversibly to monoamine oxidase thereby preventing inactivation of amines i.e. norepinephrine, dopamine and serotonin
V effective for depression
Describe the side effects of MAOIs
Orthostatic hypotension Weight gain Dry mouth Sedation Sexual dysfunction Sleep disturbance
Hypertensive crisis can occur when MAOIs taken with tyramine rich foods or sympathomimetics
What are symptoms of serotonin syndrome and when can it occur?
Can occur if MAOI taken with meds that increase serotonin or have sympathimomimetic actions
- abdo pain
- diarrhoea
- sweats
- tachycardia
- HTN
- myoclonus
- irritability
- delirium
Can lead to hyperpyrexia, CV shock and death
How can serotonin syndrome be avoided?
Wait two weeks before switching from SSRI to MAOI
Exception of fluoxetine where need wait 5 weeks due to long half-life
Describe the action of SSRIs
Block presynaptic serotonin reuptake
Treat both anxiety and depressive symtpoms
Describe side effects of SSRIs
GI upset, sexual dysfunction, nervousness, insomnia, fatigue, sedation, dizzyness
What are some SSRIs?
Fluoxetine Sertraline Paroxetine Citalopram Escitalopram Fluvoxamine
Describe the action of SNRIs
Inhibit both serotonin and noradrenergic reuptake like TCAs but without antihistamine, antiadrenergic or anticholinergic side effects
What are some SNRIs?
Venlafaxine
Duloxetine
What are some novel antidepressants?
Mirtazapine
Buproprion
What are side effects of lithium?
GI distress; reduced appetite, nausea/vom, diarrhoea
How long do you keep someone on their medication for depression?
First episode : 6 months if provides remission
Second episode : 2 years
> Third episode : discuss lifelong prophylaxis
What are indications for mood stabilisers?
Bipolar
Cyclothymia
Schizoaffective
What are the main classes of mood stabilisers?
Lithium
Anticonvulsants
Antipsychotics
What are signs of mild lithium toxicity?
Levels 1.5-2.0
vomiting diarrhoea ataxia dizziness slurred speech nystagmus
What are signs of moderate lithium toxicity?
2.0-2.5
Nausea Vomiting Anorexia Blurred vision Clonic limb movements Convulsions Delirium Syncope
What are signs of severe lithium toxicity?
> 2.5
Generalised convulsions
Oliguria
Renal failure
What is the first line agent for acute mania and mania prophylaxis?
Carbamazepine
What are side effects of carbamazepine?
Rash Nausea, vomiting, diarrhoea Sedation, dizziness, ataxia, confusion AV conduction delays Aplastic anaemia and agranulocytosis Water retention due to vasopressin-like effect; hyponatremia Drug-drug interactions
When is lithium given and when is depakote (valproic acid)?
Lithium; long term prophylaxis both manic and depressive episodes in BAD
Depakote; as effective as lithium for mania, but not for depression prophylaxis
Factors predicting good response
- rapid cycling
- comorbid substance issues
- mixed patients
- patients with co-morbid anxiety disorders
What are indications for antipsychotic use?
Schizophrenia, schizoaffective disorder, bipolar disorder (mood stabilisation and/or psychotic features present), psychotic depression, augmenting agent in treatment resistant anxiety disorders
Describe the mesocortical pathway
Projects from ventral tegmentum (brainstem) to cerebral cortex
Pathway felt to be where negative symptoms and cognitive disorders arise
Problem in a psychotic patient is TOO LITTLE dopamine
What key pathways in the brain are affected by dopamine?
Mesocortical
Mesolimbic
Nigrostriatal
Tuberoinfundibular
Describe the mesolimbic pathway
Projects from the dopaminergic cell bodies in ventral tegmentum to limbic system
Pathway is where positive symptoms arise (hallucination, thought disorder etc.)
Problem in a psychotic patient is TOO MUCH dopamine
Describe the nigrostriatal pathway
Projects from dopaminergic cell bodies in sybstantia nigra to basal ganglia
Involved in movement regulation; remember dopamine suppresses acetylcholine activity
Dopamine hypoactivity can cause Parkinsonian movements
Describe the tuberoinfundibular pathway
Projects from hypothalamus to AP
Doamine inhibits/blocks prolactin release
Blocking dopamine in this pathway will predispose patient to hyperprolactinemia
- gynecomastia, galactorrhoea, decreased libido, menstrual dysfunction
Describe typical antipsychotics
D2 domapine receptor antagonists
High potency typical antipsychoics bind to D2 receptor with high affinity
- Higher risk of extrapryamidal side effects
- Includes Fluphenazine, Haloperidol, Pimozide
Low potentcy less affinity for D2 receptors but interact with nondopaminergic receptors resulting in more cardiotoxic aand aticholinergic adverse effects; sedation and hypotension
- examples include Chloropromazine, thioridazine
Describe atypical antipsychotics
Serotonin-dopamine 2 antagonists (SDAs)
Considered atypical in that they affect dopamine and serotonin neurotransmission
examples
- risperidone
- olanzapine
- quetiapine
- aripiprazole
What is the drug of choice in psychotic treatment resistance?
Clozapine
What are adverse effects of antipsychotics?
Tardive dyskinesia; invol muscle movements that may not resolve with drug discontinuation
Neuroleptic Malignant Syndrome; severe muscle rigidity, fever, altered mental status, autonomic instability, elevated WBC, CPK and lfts. potentially fatal
Extrapyramidal side effects; acute dystonia, parkinson syndrome, akahisia
What is akathisia?
Feeling of inner restlessness and inability to stay still
What are agents for EPS?
Extrapyramidal side effects
Anticholinergics i.e. benztropine
Dopamine facilitators i.e. amantadine
Blockers propranolol
Need to watch for anticholinergic SE
What bloods do you need in a treatment naive psychotic person?
Antipsychotics may cause dyslipidaemia, abnormal LFTs and elevated blood sugars
Need;
- LFTs
- fasting lipid profile
- fasting blood sugar
- CBC
What treatement can be given for akathisia?
Need to treat as higher risk of suicide
- anxiolytic
- propranolol
What are anxiolytics?
Used to treat many diagnoses incl. panic disorder, general anxiety, substance related, insomnia and parasomnia
In anxiety disorders often use in combo with SSRIs or SNRIs
Name some anxiolytics
Buspirone
Benzos
What are side effects of benzos?
Somnolence Cognitive deficits Amnesia Disinhibition Tolerance Dependence
