Mental illness Flashcards
How many types of antipsychotic medications are there?
Two types:
1. ‘first generation’ (older; typical) antipsychotics
2. ‘second generation’ (newer; atypical) antipsychotics
Common indications for 1st generation antipsychotics?
Severe psychomotor agitation
Schizophrenia
Bipolar disorder (particularly in acute episodes of mania or hypomania)
Nausea and vomiting (particularly in palliative care setting)
What is the mechanism of action for 1st generation antipsychotics?
Blocks post-synaptic dopamine D2 receptors in the following pathways:
- mesolimbic (ML)
- mesocortical (MC)
- nigrostriatal (N)
- tuberohypophyseal (T)
How are 1st generation antipsychotics further classified?
High potency -strong antipsychotic effect at low dose
Low potency -does not tightly bind to D2 receptors and can affect other receptors (e.g. alpha-adrenergic, cholinergic, histamine receptors)
Examples of high potency 1st generation antipsychotics?
Haloperidol
Fluphenazine
Prochlorperzine
Trifluoperazine
Examples of low potency 1st generation antipsychotics?
Chlorpramazine
What are the important adverse effects of 1st generation antipsychotics?
Extrapyramidal effects (impaired motor control; N pathway affected)
- acute dystonic reactions such as involuntary parkinsonian movements or muscle spasms
- akathisia (inner restlessness)
- neuroleptic malignant syndrome (rare, but life-threatening; involves rigidity, confusion, autonomic dysregulation, pyrexia)
- tardive dyskinesia (late adverse effect; involves involuntary and repetitive movements)
Drowsiness
Hypotension
QT-interval prolongation (and consequent arrhythmias)
Erectile dysfunction
Hyperprolactinaemia (due to D2 receptors blocked in T pathway; menstrual disturbance, galactorrhoea, breast pain)
Warnings of 1st generation antipsychotics?
Elderly -sensitive to antipsychotics, hence start with lower dose.
Avoid in dementia -increased risk of death and stroke
Avoid in Parkinson’s disease -due to extrapyramidal effects (links to SEs)
Important interactions of 1st generation antipsychotics?
Any drugs that prolong the QT interval (e.g. amiodarone, macrolides)
There are many drugs that interact with antipsychotic drugs, so refer to BNF.
How are 1st generation antipsychotics monitored?
Review pt for control of symptoms and signs.
May take several wks for the drug effects to establish and reach the optimum balance of beneficial and adverse effects.
Response to high doses for acute control of psychotic/violent behaviour is unpredictable, so monitor for neurological, respiratory and cardiovascular effects.
How would you explain to the pt about taking a 1st generation antipsychotic drug?
Antipsychotic medicines aim to block certain chemicals in the brain to help control symptoms.
It may take several wks to establish its effect.
There are several side effects as with any medication, for e.g. impaired motor control, drowsiness, low blood pressure, and erectile dysfunction.
It is important to inform other healthcare professionals involved in your care because there are many medications that can play a role in how the antipsychotic medicine works.
Which 1st generation antipsychotics is commonly used for 1st line?
Haloperidol
Common indications for 2nd generation antipsychotics?
Severe psychomotor agitation
Schizophrenia
Bipolar disorder (particularly in acute episodes of mania or hypomania)
What is the mechanism of action for 2nd generation antipsychotics?
Blocks post-synaptic dopamine D2 receptors in the following pathways:
- mesolimbic (ML)
- mesocortical (MC)
- nigrostriatal (N)
- tuberohypophyseal (T)
Compared to 1st generation, the 2nd generation antipyschotics are:
- more efficacious in ‘treatment resistant’ schizophrenia
- against negative symptoms
- reduces the risk of extrapyramidal symptoms.
This could be due to higher affinity for other receptors like serotonin 2A receptor and a ‘looser’ binding to D2 receptors (e.g. clozapine, quetiapine).
What are the important adverse effects of 2nd generation antipsychotics?
Sedation
Extrapyramidal effects
Metabolic disturbance (wt gain, DM, lipid changes)
Prolong the QT interval, thus cause arrhythmias
Breast pain, swollen, galactorrhoea (men&women)
Sexual dysfunction
Agranulocytosis (low neutrophil count; clozapine effect)
Myocarditis (rare)
Warnings of 2nd generation antipsychotics?
Caution with cardiovascular disease.
Avoid in severe heart disease or hx of neutropenia.
Important interactions of 2nd generation antipsychotics?
Do not use along side:
- dopamine-blocking antiemetics
- drugs that prolong the QT interval (e.g. amiodarone, quinine, macrolides, SSRIs)
How are 2nd generation antipsychotics monitored?
Monitor symptoms and signs for tx efficacy.
Do b/t (FBC, renal, liver) at the start of tx and every week for 18 weeks, then fortnightly for up to one year, and then monthly.
Must monitor closely if pt is taking clozapine due to risk of agranulocytosis.
Monitor blood lipids and wt at baseline, 3 months, then yearly. Wt should be measured frequently during the first 3 months.
Fasting blood glucose measured at baseline, at 4-6 months, then yearly.
Patients taking clozapine should have fasting blood glucose tested at baseline, after one months’ treatment, then every 4–6 months.
How would you explain to the pt about taking a 2nd generation antipsychotic drug?
Antipsychotic medicines aim to block certain chemicals in the brain to help control symptoms.
It may take several wks to establish its effect.
There are several side effects as with any medication, for e.g. impaired motor control, agranulocytosis, breast symptoms, wt gain, and sexual dysfunction.
It is important to inform other healthcare professionals involved in your care because there are many medications that can play a role in how the antipsychotic medicine works.
If pt is taking clozapine, tell pt they need regular b/t monitoring and they need to report infection symptoms immediately.