Antipsychotic Medications Flashcards
Name some typical antipsychotics
Haloperidol
Chlorpromazine
Sulpiride
Thioridazine
What occurs at high doses of the typical antipsychotics?
Immobility, rigidity and sleep i.e. Neurolepsis
What occurs at low doses of typical antipsychotics?
An antipsychotic effects especially treating the postive symptoms. May even make negative symptoms worse
What is the mechanism of the typical antipsychotics?
They have 100 fold more potent as D2 receptors over D1 and act to antagonise them.
What is the clincal efficacy of an typical antipsychotic correlated to?
The affinity to D2 receptors over D1
What percentage of patients show no improvement on typical Aps?
25-30%
What percentage of patients show partial respite to typical antipsychotics?
25%
What are the ADRs to typical antipsychotics?
Extrapyramidal side effects Sedation Hypotension Tachycardia Neuroleptic malignancy syndrome (idiosyncratic reactions) Prolonged QT (haloperidol) Hyperprolactinaemia
Name the extrapyramidal side effects?
Akinesia
Acute dystonia
Tardative dyskinesia
Parkinsonism
What is akinesia and how many patients of typical APs get it?
~20%
Restlessness in mainly lower legs and drive to move
Slow onset
What is tardative dyskinesia and how many patients get it on typical aPs?
Involuntary movements of the Lower face muscles and tongue (80%) and limbs
It is irreversible and due to long term typical AP therapy
~50% get this
What is acute dystonia and how many patients get it?
Contraction of muscle group to maximum which is normally self limiting. Onset is within hours and reminds to anticholingeric medication (procyclidine)
~10% get this
What are the characteristic symtoms f Parkinson’s induced by typical APs how many patients get this?
Most common EPSE with onset in days/months
Tremor, bradykinesia, rigidity
~50% get severe but ~100% get mild
Why does Parkinsonism occur in typical AP treatment?
Decreasing dopamine within the brain also affects the nigrostriatal pathway. Thus, modulation of striatal outputs from the SNc is impaired.
What are the effects of typical APs in the tubuloinfundibular pathway?
Dopamine normally inhibits prolactin release. Therefore, typical APs = hyperprolactinaemia which causes sexual dysfunction, lactation and infertility.