Psychoses Flashcards
(39 cards)
What do antipsychotic medicines do?
Relieve positive psychotic symptoms e.g. thought disorder, hallucinations and delusions and prevent relapse.
Usually less effective on negative symptoms, such as apathy and social withdrawal
Mechanism of action of first generation antipsychotics
Block dopamine D2 receptors in the brain. Not selective for any of the four dopamine pathways so can cause range of side effects, including EPSE and elevated prolactin.
Types of 1st gen antipsychotics
Phenothiazine derivatives:
GROUP 1- chlorpromazine, levomepromazine, promazine
Pronounced sedative effects, moderate antimuscarinic and EPSE
GROUP 2- pericyazine
Moderate sedative effects, fewer EPSE than groups 1+3
GROUP 3- fluphenazine, perphenazine, prochlorperazine, trifluoperazine
Fewer sedative effects and antimuscarinic effects but more pronounced EPSE
Butyrophenones- benperidol and haloperidol (like the Group3 phenothiazines)
Thioxanthenes- flupentixol and zuclopenthixol- moderate sedative, antimuscarinic and EPSE
Diphenylbutylpiperidines- pimozide- and the substituted benzamides- sulpiride- have reduced sedative effects, moderate antimuscarinic and EPSE.
Antipsychotic medicines in elderly
Elderly patients with dementia- increased risk of mortality, stroke or TIA
Initial doses should be reduced
Wary of hypotension and hypo/hyperthermia
Extrapyramidal side effects
Parkinsonian symptoms- including tremor
Dystonia- abnormal face and body movements
Dyskinesia
Akathesia (restlessness)
Tardive dyskinesia (rhythmic, involuntary movements of the jaw, tongue or face) This may occur after withdrawal of the drug and may be irreversible.
Why does hyperprolactinaemia occur?
Dopamine inhibits prolactin release so increase in prolactin concentration occurs in first and second gen antipsychotics to some extent.
Aripiprazole
Reduces prolactin as it is a partial agonist of the dopamine receptor
Negligible effect on QT interval
Which antipsychotics are most likely to cause hyperprolactinaemia?
Risperidone
Amisulpride
First gen antipsychotics
Symptoms of hyperprolactinaemia
Sexual dysfunction Reduced bone mineral density Menstrual disturbances Breast enlargement Galactorrhoea
Causes of sexual dysfunction
Reduced dopamine and hyperprolactinaemia- reduce libido
Antimuscarinic effects- disorders of arousal
Alpha- adrenoceptor antagonists- erection and ejaculation problems in men
Antipsychotics that commonly cause sexual dysfunction in men
Risperidone
Haloperidol
Cardiovascular side effects with antipsychotics
Tachycardia, arrhythmias and hypotension
Which antipsychotics are more likely to cause QT prolongation?
Pimozide and haloperidol
Also more likely with intravenous use
Which antipsychotics commonly cause hyperglycaemia and sometimes diabetes?
Clozapine
Olanzapine
Risperidone
Quetiapine
Which antipsychotics commonly cause weight gain?
All antipsychotics may cause weight gain but clozapine and olanzapine do more commonly.
Which antipsychotics may cause postural hypotension?
Clozapine
Chlorpromazine
Lurasidone
Quetiapine
What is neuroleptic malignant syndrome?
Rare but potentially fatal side effect of all antipsychotics
Discontinuation essential
Bromocriptine and dantrolene have been used for treatment
Usually lasts for 5-7 days after drug discontinuation but can be worsened if depot preparations are used.
Symptoms of neuroleptic malignant syndrome
Hyperthermia Fluctuating level of consciousness Muscle rigidity Autonomic dysfunction with pallor Tachycardia Labile blood pressure Sweating Urinary incontinence
Negative symptoms of schizophrenia
Second gen antipsychotics may be better at treating the negative symptoms.
Which pathway is responsible for extra pyramidal side effects?
Blockade of the striatal dopamine pathway
Of the second gen antipsychotics, which are least likely to cause EPSE?
Clozapine
Olanzapine
Quetiapine
Amisulpride
Schizophrenia and diabetes
Schizophrenia is associated with insulin resistance and diabetes.
First gen are less likely to cause diabetes than second gen.
Which antipsychotics are least likely to cause diabetes?
1st gen- Fluphenazine + Haloperidol
2nd gen- Amisulpride + Aripiprazole
Antipsychotics with the lowest risk of sexual dysfunction
Aripiprazole and quetiapine