Antipsychotics/AntiParkinsons Flashcards
(35 cards)
Describe the mechanism of action of antipsychotics.
They block dopamine receptors (D2).
What is unique about the mechanism of action of clozapine?
It somehow selectively causes dopaminergic inhibition in the mesolimbic pathway where there is too much DA activity. It also blocks 5HT receptors somehow facilitating DA release.
*Good for refractory patients and is better against negative sx
Describe the primary physiologic problems that occur with schizophrenia.
There is too much DA activity in the nucleus accumbens, and not enough in the frontal cortex
What area of the brain is responsible for negative symptoms in schizophrenia?
The frontal cortex, where there is too little DA activity.
What area of the brain is responsible for the positive symptoms of schizophrenia?
The nucleus accumbens where there is too much DA activity
What is the primary physiologic process behind Parkinson’s?
It is caused by progressive degeneration of DA neurons int he substantia nigra. The loss of cells is correlated to clinical severity.
*Also, ACh and DA balance is disrupted.
Blockage of D2 receptors in what area of the brain in treatment of schizophrenia can cause Parkinsonian-like effects?
Blockage of D2 receptors in the striatum. Results in extrapyramidal sx (EPS, aka Parkinsonian sx)
Name the antipsychotics.
AC CHORZ - Aripiprazole, chlorpromazine, clozapine, haloperidol, olanzapine, risperidone, ziprasidone
*Having to do chores without air conditioning makes me crazy!
What is the primary aim for Parkinson’s treatment?
To treat the imbalance between striatal cholinergic and dopaminergic activity via DA replacement, enzyme inhibitors to enhance CNS deliver, MAO-B inhibition to prolong CNS effects, enhancement of DA release and blocked, and use of anticholinergics to restore balance.
What are the early side effects of antipsychotics?
Acute dystonia, akasthesia (motor restlessness), parkinsonism, neuroleptic malignant syndrome (catatonia, stupor, fever, unstable BP - this can be fatal so stop drug), sedation, seizure
What are the late side effects of antipsychotics?
Perioral syndrome (Rabbit syndrome), tardive dyskinesia (will develop in 20% of patients as result of DA receptor supersensitivity)
Describe the main physiologic disposition characteristics of antipyschotics.
Absorption is decreased by food, antacids, and anticholinergics. They concentrate in fatty tissue (good because the brain is fatty) and they’re highly protein bound.
How long does it take to achieve long-term tx of psychosis?
4-6 weeks
Describe the primary drug interactions associated with antipsychotics.
They potentiate CNS depressants, barbiturates enhance their metabolism, and anticholinergics can exacerbate confusion
What is the major drug in tx of schizophrenia?
Haloperidol
What drug is sometimes used in the acute treatment of psychotic episodes?
Chlorpromazine
Which drugs have minimal extrapyramidal symptoms (aka parkinsonian sx)
The atypicals (clozapine, risperidone, olanzapine)
Which antipsychotic was temporarily withdrawn for widened QT intervals?
Ziprasidone
*Hey QT I wanna zip you open wide
Which antipsychotics increase your risk for diabetes?
Pretty much all of them. Also can cause weight gain.
Which antipsychotic increases risk of agranulocytosis?
Clozapine
Describe the mechanism of action of aripiprazole and its clinical use.
It’s a partial D2 agonist.
Good because it decreases DA activity in accumbens where it’s too high and increases it in the frontal cortex
Which antipyschotic increases serum prolactin most markedly?
Haloperidol
Describe the mechanism of action of L-Dopa.
It is DA replacement (L-Dopa is the precursor to dopamine)
What are the side effects associated with L-Dopa?
Psychosis from overdose. In periphery conversion to DA causes nausea, palpitations, and arrhythmias, dyskinesias (from increased DA in striatum), on-off phenomenon
