Antipsychotics Flashcards
examples of typical antipsychotics
haloperidol (high potency)
chlorpromazine (low potency - so also binds to histamine, alpha adrenergic and muscarinic receptors)
examples of atypical antipsychotics
Olanzapine Clozapine Risperidone Quitiepine Aripiprazole
how to typical antipsychotics work
by blocking all D2 receptors in the brain
what effect do typical antipsychotics have on the mesolimbic pathway (via D2 receptor blockage)
reduce positive psychotic symptoms
-delusions, hallucinations etc
what effect do antipsychotics have on the mesocortical pathway (by D2 receptor blockage)
mesocortical pathway controls motor movement
D2 blockade causes extrapyramidal side effects
- tardive dyskinesias
- parkinsonism
what effect do antipsychotics have on the tuberoinfundibulnar pathway (by D2 receptor blockade)
causes increase in blood prolactin levels
this is bc dopamine regulates prolactin release from the pituitary gland
causes:
- galactorrhoea
- gynecomastia
- sexual dysfunction
what is the difference between typical and atypical antipsychotics
typical - just block D2 receptors
atypical - block D2 receptors and serotonin receptors, serotonin also blocks dopamine, so by blocking serotonin you can reduce the side effects caused by excess dopamine blockade
what receptors do atypical antipsychotics bind to other than D2
muscarinic receptors
histamine receptors
serotonin 2 receptors
alpha 1 adrenergic receptors
what is the effect of blocking alpha 1 adrenergic receptors
orthostatic hypotension
which antipsychotics block alpha 1 adrenergic receptors causing side effects
Clozapine
Risperidone
what are the side effects of serotonin 2 receptor blockade
metabolic side effects
- weight gain
- hyperglycaemia
- dyslipidaemia
which atypical antipsychotics block serotonin 2 receptors
Olanzapine
Clozapine
what are the side effects of blocking H1 histamine receptors
sedation
weight gain
which atypical antipsychotics block H1 receptors
clozapine
Quitiepine
olanzapine
which atypical antipsychotic has the strongest affinity for D2 receptors and therefore has the highest potential to cause extrapyramidal side effects and elevated prolactin
risperidone
which antipsychotic can cause agranulocytosis
Clozapine
what are the side effects of muscarinic receptor blockade
anti-cholinergic effects
blurred vision
constipation
urinary retention
dry mouth
which antipsychotics are most likely to cause anti-cholinergic side effects
haloperidol
chlorpromazine
if a patient has missed 2 doses of clozapine how do you restart it
if treatment is missed for >48 hours then restart titration to reduce the risk of side effects
start at 12.5 mg and titrate up to effect
what are the main side effects of clozapine
agranulocytosis/neutropenia myocarditis and cardiomyopathy tachycardia seizures hypersalivation
what drug can be co-prescribed with clozapine to increase white cell count
lithium
risk factors for neuroleptic syndrome
rapid antipsychotic dose increase IM route medical illness male gender dehydration
presentation of neuroleptic malignant syndrome
hyperthermia (v high temp) muscle rigidity decreased conscious level labile blood pressure (easily changing) elevated creatinine kinase leucocytosis abnormal LFTs myoglobinuria
treatment of neuroleptic malignant syndrome
stop antipsychotic
supportive treatment
dopamine agonists (to reverse the anti-dopaminergic effects and muscle spasms)
