Antipsychotics Flashcards
What are examples of first-generation antipsychotics?
Haloperidol, chlorpromazine, pericyazine
Typical antipsychotics MOA?
Post-synaptic blockade of the D2 receptor
Pharmacology of typical antipsychotics?
Extensively metabolised by CYP450 system thus susceptible to hepatic impairment and drug-drug interactions.
Highly lipophilic, protein and tissue bound, with a large volume of distribution thus effect is variable and unpredictable in different patients.
Side effects of typical antipsychotics?
My Cute Cat Makes The Purring Sounds:
Metabolic syndrome Cardiovascular (QT prolongation, hypotension) Motor symptoms (rigidity, bradykinesia) Tardive dyskinesia Prolactin elevation Sexual dysfunction
What are examples of second-generation antipsychotics?
Risperidone, olanzapine, quetiapine, aripiprazole, clozapine (CROAQ)
Atypical antipsychotic MOA?
Post-synaptic blockade of the D2 receptor. Has some affinity for the 5HT2A receptor; inhibition of serotonin increases dopamine release (which may account for the decrease EPSE)
Pharmacology of atypical antipsychotics?
Variable activation by CYP450 system therefore some drugs are susceptible to hepatic impairment and drug-drug impairment.
Side effects of atypical antipsychotics?
Metabolic syndrome QT prolongation Cardiovascular effects Motor symptoms Tardive dyskinesia (to a lesser extent than FGA) Prolactin elevation Sexual dysfunction.
What are the differences between atypical and typical antipsychotics, and why?
Atypical antipsychotics are associated with lower rates of motor symptoms and tardive dyskinesia. This is likely to due to the fact that atypical antipsychotics have some affinity for the 5HT2A receptor, which causes an increase in dopamine release.
What are the indications for clozapine?
Schizophrenia or schizoaffective disorder not responsive to other antipsychotics
What is included in the pretreatment assessment of clozapine?
Complete blood count
Weight, BSLs, lipids
What monitoring is required for clozapine?
Neutrophil counts due to risk of neutropenia within 10 days of first administration, every week for the first 18 weeks, and every four weeks thereafter. This is a legal requirement.
What are the side effects of clozapine?
Myocarditis Cardiomyopathy Gastrointestinal hypomotility Metabolic side effects Neutropenia
When would clozapine levels be taken?
To assess adherence or in the case of poor clinical response. This is because therapeutic levels are highly individual.
What are the problems that can occur due to switching antipsychotics?
Rebound psychosis Cholinergic rebound Dystonia Akathisia Histamine rebound
What is myocarditis?
Inflammation of the heart muscle, usually occurs in the first two months of use.
What is cardiomyopathy?
Weakness of the heart muscle/heart failure
What is GI hypomotility?
Slowing down of peristalsis in the GI tract which causes constipation.
According to the Porirua Protocol, what are the steps of managing Clozapine-induced constipation?
Laxsol 2 tabs nocte and monitor
Then increase by one tab of laxsol every 2 days
Then inspect for fecal impacting and add macrogol sachet
Finally discuss with specialist for individual regime (usually includes macrogol and enema)
What is rebound psychosis and how is it managed?
When psychosis symptoms reemerge following change in therapy. Managed with benzos and antipsychotic
What is cholinergic rebound and how is it managed?
Re-emergence of EPSEs. In mild cases wait for it to resolve. In severe cases add on an anticholinergic.
How is dystonia/parkinsonism managed?
Add or restart anticholinergic and slow down titration
What is akathisia and how is it managed?
Restlessness and agitation. Managed with beta blockers (e.g. propranolol) or benzos
What is histamine rebound and how is it managed?
Reemergence of histamine-induced symptoms (e.g. allergy), treated with benzos or antihistamines.
What antipsychotics are best for the treatment of schizophrenia and why?
Aripiprazole: second generation therefore less risk of EPSE, most tolerable ADR profile thus recommended.
What makes antipsychotics beneficial for the treatment of bipolar?
Antagonism of dopamine and serotonin receptors can reduce psychotic symptoms in mania
Which antipsychotics are best for treating bipolar?
Quetiapine, olanzapine.
