Antipsychotic drugs Flashcards
List typical/first generation antipsychotic drugs
Haloperidol and -azine drugs:
-chlorpromazine/haloperidol
What is the main mechanism of action for first generation antipsychotic drugs?
-dopamine receptor blockade (D2 receptors)
What are the side effects of first generation antipsychotic drugs? (7)
- Cardiac: Long QT interval
- Anticholinergic effects: blurred vision/dry mouth/urinary retention
- Antihistamine effect: sedation/inc. appetit
- Anti-alpha1 effect: orthostatic hypotension
- Dopamine blockade on tuberoinfudibular pathway: hyperprolactinaemia (osteoporosis/amenorrhea/galactorrhea/gynaecomastia/sexual dysfunction)
- Dopamine blockade in basal ganglia: Extrapyramidal symptoms
- Neuroleptic malignant syndrome
What is neuroleptic malignant syndrome? when does it occur? what to treat?
Either initiation of neuroleptics or withdrawal of antiparkinsonian medication
-fever/hyperthermia
-muscular rigidity (lead pipe)
-alteration in mental status e.g. confusion
-autonomic dysfunction e.g. pallor, tachycardia, fluctuating blood pressure, excessive sweating/salivation, tremor and incontinence.
Treat with dantrolene
What causes the extrapyramidal side effects that occur with first gen. antipsychotics?
dopamine blockade on the nigrostriatal pathway
Describe the extrapyramidal side effects that occur with first generation antipsychotics in:
- hours to days
- days to weeks
- weeks to months
- month to years
ADAPT
Hours to days: Acute Dystonic rxn - sustained muscle contraction, treat with IM diphenhydramine or benztropine
Days to weeks: Akathisia (restlessness)
Weeks to months: Parkinsonism (tremor/ cogwheel rigidity/hypokinesia)
Months to years: Tardive dyskinesia
Treat by switching FGA-SGA or SGA-Clozapine
Give some examples of second generation antipsychotic drugs
- aripripazole
- apines e.g. quetiapine/clozapine/olanzapine
- idones e.g. respiradone
What is the mechanism of action of second generation antipsychotic drugs compared with first? (apart from clozapine)
-weaker D2 blockade and serotonin agonism except aripripazole which is a partial D2 agonist
What side effects are associated with second generation antipsychotics compared with first generation?
- Delay cardiac conduction (Long QT)
- less anticholinergic and extrapyramidal side effects
- apines cause metabolic syndrome (weight gain/diabetes/hyperlipidaemia)
What two side effects does clozapine cause? Therefore how are patients monitored?
- paralytic ileus: can cause gastric perforation
- Agranulocytosis: FBC weekly for 1st 6months, fortnightly 2nd 6mths, four weekly thereafter
What is the mechanism of action of clozapine?
- D4 receptor blockade
- little effect on D2 receptors - little/no extrapyramidal SE
- potent muscarinic M4 receptor agonist = Drooling
When is clozapine indicated?
Refractory to 2 different antipsychotics.
