Psychopharmacology - antipsychotics Flashcards
1
Q
Indications for antipsychotics
A
- Schizophrenia
- Schizoaffective disorder
- Bipolar disorder → mood stabilisation +/- psychotic features
- Psychotic depression
- Treatment resistant depression and anxiety → augmenting agent
2
Q
Mechanism of antipsychotics
A
- Affect dopaminergic pathways of the brain
- Nigrostriatal
- Mesolimnic
- Mesocortical
3
Q
Mesocortical pathway
A
- Projection of ventral tegmentum (brain stem) to cerebral cortex
- Symptoms → negative symptoms, cognitive disorders (executive dysfunction)
- Disorder → Caused by too little dopamine
4
Q
Mesolimbic pathway
A
- Ventral tegmentum → limbic system
- Symptoms → positive symptoms (hallucinations, delusion and thought disorders)
- Disorder → too much dopamine
5
Q
Nigrostriatal pathway
A
- Substantia nigra → basal ganglia
- Involved in regulation of movement (dopamine suppresses acetylcholine activity)
- Disorder → dopaminergic hypoactivity
- Symptoms → Parkinsonism (rigidity, bradykinesia, tremors, akathisia, dystonia
6
Q
Tuberoinfundibular
A
- Hypothalamus → anterior pituitary
- Function → dopamine regulates. inhibits prolactin release
- Blocking prolactin → Hyperprolactinemia (gynaecomastia, galactorrhea, lowered libido, menstrual dysfunction)
7
Q
Typical antipsychotics
A
- D2 dopamine receptor antagonist
- High potency
- High affinity to D2 receptor
- Risk of extrapyramidal side effects
- E.g fluphenazine, haloperidol, pimozide
- Low potency
- Low affinity to D2 receptor, interact with nondopaminergic receptors
- Risk of cardiotoxic, anticholinergic side effects
- Chlorpomazine
8
Q
Atypical antipsychotics
A
- Serotonin-dopamine 2 antagonists (SDAs)
- Atypical due tot affinity for serotonin and dopamine in all 4 dopaminergic pathways
9
Q
Risperidone
A
- Regular tab, rapid tab and IM
- Functions like a typical antipsychotic
- Dose dependant extrapyramidal side effects
- Side effects → Hyperprolactinemia, sedation, weight gain
10
Q
Olanzapine
A
- Regular tab, immediate release IM, rapid tab,
- Side effects
- Extreme weight gain (30-50 pounds)
- Hyperprolactinoma
- Hypertriglyceridemia, hypercholesterolemia, hyperglycaemia
- Abnormal LFT’s
11
Q
Quetiapine
A
- Regular form only
- Side effects
- Abnormal LFTs
- Weigh gain
- Hypertriglyceridemia, hypercholestrolemia, hyperglycaemia
- Orthostatic hypotension
12
Q
Aripiprazole
A
- Regular tab, immediate release IM and depo
- Mechanism → D2 partial agonist
- Low extrapyramidal side effects, no QT prolongation, low sedation, weight neutral
- Interactions → CYP2D6 (fluoxetine, paroxetine), 3A4 (carmamazepine)
13
Q
Efficacy
A
- All have similar efficacy
- Choice based on side effect profile
- ⅓ good response, ⅓ some response, ⅓ no response
14
Q
Clozapine
A
- Regular tabs only
- Reserved for treatment resistant patients
- Side effects
- Agranulocytosis
- Risk of seizure (in combo with lithium)
- Sedation
- Weight gain
- Abnormal LFT
- Risk of high triglycerides, cholesterol, glucose → coma and death
15
Q
Adverse effects of antipsychotics
A
- Tardive dyskinesia → involuntary muscle movements, may not resolve after discontinuation
- Neuroleptic malignant syndrome → severe muscle rigidity, fever, altered MS, autonomic instability, elevated WBC/CPK/ LFT
- Extrapyramidal side effects → acute dystonia, Parkinsonism, akathisia
