pharmacology of antipsychotics Flashcards
what causes positive symptoms in schitzophrenia?
Positive symptoms are caused by too much dopamine in the mesolimbic pathway
(subcortical dopamine hyperactivity)
Mesolimbic pathway is from:
Ventral Tegmental Area (VTE) -> Nucleus Accumbens (NA)
what is the mesolimbic dopamine pathway?
from the Ventral Tegmental Area (VTA) -> Nucleus Accumbens (NA)
What causes negative symptoms in schitzophrenia?
Negative symptoms are caused by a reduction of dopamine in the mesocortical pathway
(frontal dopamine hypoactivity)
Mesocortical pathway is from:
Ventral Tegmental Area (VTE) -> Cortex
what is the mesocortical pathway?
from the Ventral Tegmental Area -> Cortex
what is used to treat positive symptoms?
Dopamine antagonist antipsychotics
-because positive symptoms are due to dopamine hyperactivity in the subcortical area (mesolimbic pathway from VTA-> nucleus acumbens)
what dopamine pathway is involved in movement?
Nigrostriatal pathwy
Substantia Nigra -> Striatum (caudate + putamen)
What is the nigrostriatal pathway?
Dopamine pathway controlling movement
From Substantia Nigra -> Striatum (caudate + putamen)
What affect can antipsychotics have on the nigrostriatal pathway and how may it present?
Antipsychotics decrease dopamine levels in the nigrostriatal pathway and can induce Parkinsonism (extrapyramidal motor symptoms)
What is the tuberoinfindibular pathway?
Hypothalamus -> Pituitary gland
what releases prolactin?
pituitary gland
what is the relationship between dopamine and prolactin?
inverse relationship
increase in dopamine leads to a decrease in prolactin
what affect can antipsychotics have on the tuberoinfundibular pathway and how may this present?
Antipsychotics decrease levels of dopamine in Hypothalamus causing increase levels of Prolactin in Pituitary
Increase Prolactin:
-Decrease FSH and lead to Amenorrheoa
-Galactorrhoea
examples of typical/ first generation antipsychotics?
-Haloperidol
-Chlorpromazine
-Zuclopenthixol
-Flupentixol
-Trifluoperazine
-Prochlorperazine
MofA of antipsychotics?
Antagonists of:
-Dopamine (D2) Receptor
-Histamine (H1) Receptor
-Adrenoceptors (alpha 1) Receptor
-Muscarinic (M1) Receptor
Dopamine - most obvious
HAM- these people be going ham so give them an antipsychotic!
SE of histamine (H1) receptor antagonist?
weight gain + sedation
SE of adrenoceptor (alpha 1) receptor antagonist?
-hypotension
-priapism (prolonged erection)
SE of muscarinic (M1) receptor antagonist?
anticholinergic SE:
-dry mouth
-constipation
-dilated pupils
What type of antipsychotics are more likely to give you extrapyramidal symptoms?
1st generation AKA typical
Examples:
-Haloperidol
-Chlorpromazine
-Zuclopenthixol
-Flupentixol
-Trifluoperazine
-Prochlorperazine
what type of antipsychotics are more likely to cause Neuroleptic Malignant Syndrome?
1st generation AKA typical
Examples:
-Haloperidol
-Chlorpromazine
-Zuclopenthixol
-Flupentixol
-Trifluoperazine
-Prochlorperazine
examples of 2nd generation AKA atypical antipsychotics?
-Clozapine
-Olanzapine
-Quetiapine
-Risperidone
-Paliperidone
-Lurasidone
-Ariprazole