Antipsychotics Flashcards
What are antipsychotics indicated for?
- Psychosis
- Schizophrenia
- BiPolar Disorders
Name 2 typical Antipsychotics
- Haloperidol (Haldol)
- Flupentixol Decanoate (Depixol)
Name 5 A-typical Antipsychotics
- Olanzapine
- Quetiapine
- Risperidone
- Aripiprazole
- Clozapine
Talk to me about the DA theory of Sz?
- Based on the Dopamine Theory of Schizophrenia that Sz caused by high levels of DA
- discovered by accident (amphetamine psychosis and parkinson medication Levadopa which lead to increased DA showed similar side effects)
- BUT neurochemical changes in brain occur immediately after taking APs, yet it can take days/weeks to see observable (‘behavioural’) changes (epigenetics?)
What is the mechanism of action of Typical Antipsychotics?
- Act predominantly by blocking (antagonising) D2 receptors in the brain.
- Not selective for any of the four dopamine pathways in the brain, hence side effects.
What is the mechanism of action of Atypical Antipsychotics?
- Similar to Typical APs
- However do not exclusively block DA but act on a range of receptors, including;
- D1, D2, 5-HT, H-1 R and alpha-adrenoceptor antagonists
- This could explain why Atypicals have an effect on negative symptoms when typicals do not
Which Atypical Antipsychotic has a slightly different mechanism of action?
Aripiprazole is a partial D2 agonist;
- acts as an antagonist where high concentration of DA
- acts as an agonist where low concentrations of DA
It also has weak 5-HT partial agonism
What is specific to Olanzapine and Clozapine?
- Mechanism of action; also antagonise muscarinic receptors (Acetylcholine-GPCRs, excitatory/inhibitory)
- increased risk of metabolic syndrome (more than just via increase in body weight)
What are the shared side effects of Antipsychotics, and main differences between the two types?
- Sleepiness and feeling ‘slowed down’ in thinking
- Constipation
- Hypotension (and linked dizziness)
- Main concern with Typicals is EPSEs
- Main concern with Atypicals is metabolic syndrome
- but both share both!
What are the shared side effects of Typical Antipsychotics?
- EPSEs
- Sexual side effects (reaching climax, difficulty achieving arousal for both)
- Hyperprolactinaemia (sexual dysfunction, reduced bone density, menstrual disturbances)-n.b. DA inhibits prolactin release!
What are the shared side effects of Atypical Antipsychotics?
- dry mouth
- weight gain (suggested average long term weight increase of >25%)-NOT Aripiprazole
- increased risk of metabolic syndrome (more than just via increase in body weight)-particularly Olanzapine and Clozapine
What are some of the side effects specific to Aripiprazole?
- Insomnia
- blurred vision
- restlessness
What are the four main types of Extra Pyramidal Side Effects?
- Dystonia (sudden involuntary movement and muscle contractions, hypersalivation, mouth/tongue movements, abnormal eye rolling ‘oculogyric crisis’). Usually within 1st week
- Akathisia (motor restlessness, inability to sit still)
- Pseudo Parkinsonism (cogwheel rigidity, drooling, shuffling gait, tremors). stop if drug withdrawn.
- Tardive Dyskinesia (irregular/jerky movements, lip smacking, chewing, slow and aimless arm movements). Usually after 6+ months and are hard to reverse
What are the nursing actions for EPSEs?
For Dystonia/Akathesia/Pseudo Parkinsonism;
- Reducing dose
- Switching to atypical
- anticholinergic medication-procyclidine
- use of a benzodiazepine
Diskenesia
- discontinuation
- increase vitamin e
Dangerous complications of all Antipsychotics
- High risk of cardiac complications
- Neuroleptic Malignant Syndrome