Antipsychotics Flashcards
What are the 4 dopamine pathways of the brain?
Mesolimbic
Mesocortical
Tuberoinfundibular
Nigrostriatal
What is the mesolimbic pathway in schizophrenia?
Overactive in schizophrenia due to too much dopamine
- Causes positive symptoms
What is the mesocortical pathway in schizophrenia?
Underactive in schizophrenia due to reduced dopamine
- Causes negative symptoms
When antipsychotics are administered, this affects the tuberoinfundibular pathway, what side-effects are produced?
(Increased prolactin) galactorrhoea, gynaecomastia, amenorrhoea and sexual dysfunction.
Typically due to 2nd gen (atypical antipsychotics).
When antipsychotics are administered, this affects the nigrostriatal pathway, what side-effects are produced?
Extra-pyramidal side effects include:
Parkinsonism
Acute dystonia (muscle spasm)
Akathisia (severe restlessness – fidgeting, pacing, constant need to move)
Tardive dyskinesia (late onset of chorea, lip smacking, pouting of jaw, chewing, sticking tongue out, blinking)
What does blocking of alpha receptors (alpha blockers) lead to?
Orthostatic hypotension
What does blocking of cholinergic receptors (anti-cholinergic drugs) lead to?
Dry mouth
Blurred vision
Constipation
Urinary retention
What does blocking of H1 receptors lead to?
Sedation
Weight gain
Examples of 1st gen (typical) antipsychotics?
Haloperidol
Prochlorperazine
Fluphenazine
Chlorpromazine
Trifluperazine
Mechanism of action for 1st gen antipsychotics?
NON-SELECTIVELY block D2 (D2 antagonists) and other receptors
Benefit of 1st gen antipsychotics in schizophrenia?
Reduce positive symptoms (acting on mesolimbic pathway)
Downside of 1st gen antipsychotics in schizophrenia?
Worsens negative symptoms
Side effects of 1st gen antipsychotics?
Extra-pyramidal side effects (main side-effects)
Gynaecomastia
Galactorrhoea
Amenorrhoea
Sexual dysfunction
Orthostatic hypotension
Anti-cholinergic side effects
Sedation
Weight gain
What is haloperidol commonly used for?
Delirium or psychosis
What are side-effects of specifically haloperidol?
Prolonged QT
Neuroleptic malignant syndrome (pyrexia/fever + muscle stiffness)
Examples of 2nd gen (atypical) antipsychotics?
Olanzapine
Risperidone
Quetiapine
Aripiprazole
Clozapine
Amisulpride
Lurasidone
Mechanism of action for 2nd gen antipsychotics?
Work on D2 and 5HT-3 (serotonin) to reduce side effect profile
Also works on H1, alpha and cholinergic
Benefits of 2nd gen antipsychotics in schizophrenia?
Improves positive symptoms
No worsening of negative symptoms
Less likely to cause extra-pyramidal side effects
What 2nd gen antipsychotic is most likely to cause increased extra-pyramidal side effects and increased prolactin side effects?
Risperidone
Specific side-effects for olanzapine?
Metabolic syndrome (hyperglycaemia, hyperlipidaemia, weight gain and sedation)
Specific side-effects for quetiapine?
Sedation and weight gain
Specific side-effect for risperidone?
Galactorrhoea
Specific side-effects for clozapine?
Agranulocytosis (decreased granulocyes i.e. basophils, neutrophils, eosinophils)
Neutropenia (decreased neutrophils)
Seizures
Metabolic syndrome
Weight gain
Sedation
What 2 tests should be done before starting patient on clozapine?
ECG (since can cause metabolic syndrome and myocarditis so baseline ECG required)
FBC (full blood count)
What antipsychotic is used for treatment resistant schizophrenia?
Clozapine
How often is FBC carried out with clozapine therapy?
FBC every week for 18 weeks then every 2 weeks thereafter
After 1 year of monitoring, check FBC every 4 weeks
What must patient notify clinician about during clozapine therapy?
Patient must notify if started or stopping smoking
Treatment for tardive dyskinesia?
tetrabenazine
Treatment for acute dystonia?
pyrocyclidine
