Antipsychotics Flashcards
What is the mechanism of action of typical antipsychotic drugs?
Dopamine D2 receptor antagonists:
blocking dopaminergic transmission in the mesolimbic pathways
What is the MOA of atypical antipsychotic drugs?
Block:
dopamine D2 receptors
serotonin 5-HT2A receptors
What are the common SE of typical antipsychotics?
Extrapyramidal side-effects: dystonia, akathisia, parkinsonism, tardive dyskinesias
Hyperprolactinaemia: galactorrhea, gynaecomastia, amenorrhoea
What are the SE of atypical antipsychotics?
Metabolic: weight gain, impaired glucose tolerance
EPSE + hyperprolactinaemia less common
Why do atypical antipsychotic drugs have fewer side effects than typicals?
Weaker D2 antagonism
What class of drug is the first line treatment in schizophrenia?
Atypical antipsychotics
In the elderly, what extra risk do antipsychotic drugs carry?
Increased risk of stroke + VTE
Recall 2 examples of typical antipsychotics
Haloperidol
Chlorpromazine
Recall 4 examples of atypical antipsychotics
Clozapine
Risperidone
Olanzapine
Quetiapine
Aripiprazole
What is akathisia?
Severe restlessness
What is tardive dyskinesia?
Rhythmic involuntary movements of the mouth, face, limbs + trunk e.g. chewing + pouting of jaw
IRREVERSIBLE
Give 2 examples of acute dystonia
Torticollis
Oculogyric crisis
List 4 anti-muscarinic symptoms caused by antipsychotics
Dry mouth
Blurred vision
Urinary retention
Constipation
Describe how the dosage of clozapine is controlled
Start low + go slow
If >48h missed medication, need to start again
Recall one caution of using clozapine
If patient stops smoking suddenly, clozapine levels will suddenly rise
Which typical antipsychotic in particular is associated with a prolonged QT interval?
Haloperidol
Which class of antipsychotics has a greater association with reduced seizure threshold?
Atypical
Give 3 significant side effects to remember for clozapine
AGRANULOCYTOSIS
Neutropenia
Reduced seizure threshold
Which antipsychotic has a generally good side-effect profile, particularly for prolactin elevation?
Aripiprazole
Which antipsychotic is particularly associated with obesity and dyslipidaemia?
Olanzapine
What is thought to cause neuroleptic malignant syndrome?
Dopamine blockade induced by antipsychotics triggers massive glutamate release and subsequent neurotoxicity and muscle damage
Describe the onset of neuroleptic malignant syndrome
hours-days of starting an antipsychotic
Give 5 features of neuroleptic malignant syndrome
Pyrexia
Muscle rigidity
Autonomic lability: HTN, tachycardia + tachypnoea
Agitated delirium with confusion
Seizures
What makes neuroleptic malignant syndrome different to serotonin syndrome?
NMS: normal pupils + hyporeflexia
SS: dilated pupils + hyperreflexia
What is the treatment for neuroleptic malignant syndrome?
Dantrolene
What physiological markers change in neuroleptic malignant syndrome?
Raised Creatine Kinase
+/- AKI secondary to rhabdomyolysis if severe
+/- leukocytosis
Describe the monitoring process for patients who take antipsychotic medications
FBC, U+Es, LFTs: at start, annually
Lipids, weight: at start, 3m, annually
Fasting blood glucose, prolactin: at start, 6m, annually
BP: baseline + frequently during dose titration
ECG: baseline
CVD risk assessment annually
When should an FBC be done in a patient taking clozapine?
At frequent intervals for monitoring + every time there’s an infection as need to check there’s no agranulocytosis
What extra monitoring is required for clozapine?
Monitor leucocyte + differential blood counts.
Differential WCC monitoring weekly for 18w
Then fortnightly for up to 1y
Then monthly
