Class 3-psychotic disorders Flashcards
INDUCED PSYCHOTIC DISORDERS- MEDICATION
o Dopamine agonists o Chloroquine o Corticosteroids o Fluoroquinolones o Stimulants * Several other drugs suspected in case reports
DOES CANNABIS CAUSE SCHIZOPHRENIA?
o Patients who have genetic predisposition may be at greater risk o Other risk factors : - Earlier age of cannabis use - Frequency of use - THC potency
NEUROTRANSMITTERS INVOLVED with psychotic disorders
- Dopamine
- Serotonin
- Glutamate
- GABA
- Acetylcholine
DOPAMINE (DA)- RECEPTORS
D1 to D5
PHARMACODYNAMICS, which one:
TRANSPORTERS G-PROTEIN-COUPLED RECEPTORS
ENZYMES ION CHANNELS
G-PROTEIN-COUPLED RECEPTORS
Dopamine binds to what receptor
D2 receptors
DOPAMINE PATHWAYS
A. MESOLIMBIC PATHWAY
B. MESOCORTICAL PATHWAY
C. NIGROSTRIATAL PATHWAY
D. TUBEROINFUNDIBULAR PATHWAY
MESOLIMBIC PATHWAY
Pleasure, euphoria, interest, energy, dependance
MESOCORTICAL PATHWAY
Dorsolateral area : intellectual functions
Ventral tegmentum area : integration of emotions
NIGROSTRIATAL PATHWAY
Relay for motor behavior
VOIE TUBÉRO-INFUNDIBULAIRE
Regulates prolactin secretion
MESOLIMBIC PATHWAY- SCHIZOPHRENIA
- «Hyperactivity » or excess dopamine
- Contributes to positive symptoms of schizoprenia
- e.g. hallucinations, delusions
MESOCORTICAL PATHWAY- SCHIZOPHRENIA
- «Hypoactivity » or lack of dopamine
- Contributes to negative symptoms of schizophrenia
1ST GENERATION ANTIPSYCHOTICS
CLASSIFICATION BY POTENCY
HIGH POTENCY
• + incisive, better effect on psychotic symptoms
• E.g. haloperidol: very specific only binds to D2
MEDIUM POTENCY
• E.g. loxapine
LOW POTENCY
• + sedative, better effect on agitation
• E.g. chlorpomazine
1ST GENERATION ANTIPSYCHOTICS- ????? RECEPTOR ????
D2 antagonist
NIGROSTRIATAL PATHWAY- D2 RECEPTOR ANTAGONIST
Variety of movement disorders named extrapyramidal symptoms (EPS)
DYSTONIA
Description: Bizarre, involuntary tonic contractions of skeletal muscle; most common dystonias are buccal spasms, oculogyric crisis, facial grimacing er tics
Onset: - Usually within 24 – 96 h of medication initiation or dose change
- Can sometimes come later during treatment or on
discontinuation of treatment (withdrawal dystonia)
Incidence - 0,6 – 8,3 %
Risk factors /antipsychotics involved
- Younger men
- High potency antipsychotic (e.g. haloperidol) and increased dose
DYSTONIA
PREVENTION
- Start the antipsychotic at a low dose
- Gradually increase the dose
- Plan for the administration of an anticholinergic drug if the patient as an antecedent of dystonic reaction
- e.g. during agitation
DYSTONIA
TREATMENT
- Reduce dose or change antipsychotic
- Mild to moderate symptomss :
- Benztropine 1 – 2 mg PO
- Diphenhydramine 25 – 50 mg PO
- Moderate to severe symptoms :
- Benztropine 1 – 2 mg IM
- Diphenhydramine 25 – 50 mg IM
AKATHISIA
Description: Feeling of distress or discomfort, often referred to legs; inner or motor restlessness, inability to sit or stand still.
Onset - Often within the first 2 to 3 weeks after starting treatment
- 90 % dans les 2 premiers mois
Prevalence - 35 %
Risk factors / antipsychotics involved - Aripiprazole and lurasidone often involved in practice
AKATHISIA
PREVENTION
- Start the antipsychotic at a low dose
- Gradually increase the dose
AKATHISIA
TREATMENT
- Reduce dose or change antipsychotic
- Beta-blocker (e.g. propranolol 10 mg BID)
- Side effects : ↓HR, hypotension
- Benzodiazepines (e.g. lorazepam, clonazepam)
- Use the smallest effective dose
- Anticholinergics less effective than in other EPS
PSEUDOPARKINSONISM
Description Generalized slowing of involuntary movements (bradykinesia/akinesia) with masked facies and reduction in arm movement; most noticeable
signs are rigidity (cogwheel) and tremor at rest
* Bradykinesia : motor retardation
** Akinesia : decrease in spontaneous movements
Onset
- Usually develops several days after treatment initiation
Prevalence - Variable : 20- 35 %
Risk factor / antipsychoticsinvolved
- Female gender
- Increased age
- High potency antipsychotics (mostly FGA) and increased dose
PSEUDOPARKINSONISM
PREVENTION
- Start the antipsychotic at a low dose
- Gradually increase the dose