Antipsychotics Flashcards
What are the 5 main dopamine pathways in the brain?
Mesolimbic pathway mesocortical pathway nigrostriatal pathway tuberoinfundibular pathway hypothalamospinal pathway
What are the dopaminergic side effects?
extra pyramidal side effects + neuroleptic malignant syndrome + hyperprolactinaemia + akathesia/restless legs
What are 3 examples of extra pyramidal side effects?
Acute dystonic reaction
parkinsonism
tardive dyskinesia
Describe acute dystonia presentation?
- onset in minutes
- increasing muscle tone
- energetic
- torticolis (head to one side as neck muscles contracted)
- oculogyric crisis (eye muscles all contract, eyes deviate upwards)
- tongue protrusion
What other drugs other than antipsychotics can cause acute dystonia?
Antihistamines
antiemetics
Describe tardive dyskinesia presentation.
often after years of treatment - permanent
involuntary repetitve oro-facial movements
blinking, grimacing, pouting, lip-smacking common
may involve limbs and/or trunk
Why are anticholinergic drugs used to treat extra-pyramidal side effects of antipsychotics?
to balance out the acetylcholine and dopamine = there is less dopamine as dopamine has been inhibited and so acetylcholine is in excess in comparison to dopamine
List 3 anticholinergic drugs used to alleviate side effects from antipsychotics
procyclidine
trihexyphenidyl
orphenadrine
In neuroleptic malignant syndrome what dopamine pathways are affected?
Hypothalamic
Nigrostriatal
Tardive dyskinesia is treatable. True/false
False - very difficult to treat once caused by antipsychotics
How does neuroleptic malignant syndrome present?
1-3 days onset gradually increasing muscle tone hyperpyrexia autonomic instability often FATAL!! if not treated
How does neuroleptic malignant syndrome lead to death?
increasing muscle tone -> rhabdomyolysis -> Acute renal failure -> coma -> death
What is the key investigation for neuroleptic malignant syndrome?
Creatinine Kinase
What is the treatment for neuroleptic malignant syndrome?
A&E!!!
- Stop antipsychotic
- renal support
- rapid cooling
- skeletal muscle relaxants e.g. dantroline
- dopamine agonists e.g. bromocriptine
What dopaminergic pathway is affected in hyperprolactinaemia side effect of antipsychotics?
Tuberoinfundibular
What dopaminergic pathway is affected in akathisia caused by antipsychotics?
Hypothalamic spinal pathway
How many patients report akathisia?
1/5
How does akathisia present?
within days-weeks pacing rocking from foot to foot unable to sit still bad sleep as result leads to suicide risk
What are the treatments for akathisia?
first line: beta blockers e.g. propranolol
second line: long acting benzodiazepines e.g. clonazepam
What are 3 anti-cholinergic effects?
dry mouth
blurred vision
constipation
What are 5HT2 side effects?
weight gain -> metabolic syndrome -> T2DM
What is an example of anti-adrenergic effect?
Postural hypotension
What neurotransmitter do benzodiazepines enhance?
GABA which is a neurotransmitter that suppresses the activity of nerves
What are 3 other side effects of antipsychotics?
hepatotoxicity
prolonged QTc interval
photosensitivity
Generally first/second generation antipsychotics are thought to cause more weight gain and sedation and first/second generation antipsychotics are thought to cause more extra-pyramidal side effects side effects?
Second gen - weight gain & sedation
First gen - EPSE
approx. what percentage of patients experience neuroleptic malignany
What is the best antipsychotic including for the negative syndrome?
Clozapine
What are the side effects of clozapine?
agranulocytosis - need white cell count monitoring regularly
myocarditis - need ECG monitoring regularly
constipation (most dangerous side effect!!)
weight gain
sedation
sialorrhoea
What approach is used when picking an antipsychotic for treating schizophrenia?
First step: 2nd generation titrate to adequate dose for 6-8wks
If not working, next: 1st/2nd generation titrate to adequate dose for 6-8 wks
Next: check diagnosis, consider psychological input, check compliance
Last: clozapine or combine two antipsychotics
Which are considered first line in treating schizophrenia - typical/atypical? Give two examples of both.
Atypical first
Atypical examples: risperidone, olanzapine
Typical examples: haloperidol, chlorpromazine
Which type (typical/atypical) of antipsychotics are better when treating negative syndrome schizophrenia?
Atypical
Which type (typical/atypical) of antipsychotics are better when treating negative syndrome schizophrenia?
Atypical
What is the main mechanism behind antipsychotics?
Dopamine antagonists - aim to block D2 receptors but block others too
What pharmacological options is there for when a patient with schizophrenia becomes agitated, uncooperative, aggressive?
Benzodiazepines: Lorazepam oral/IM
Antipsychotics: Haloperidol/olanzapine oral/IM
Sedating antihistamines: promethazine oral/IM
