Which one of the following regarding buspirone is true? It is:
D. Buspirone is a partial agonist at 5HT1A. It is used in generalized anxiety disorder and as an augmenting agent to treat resistant depression. It does not have an action on the GABA receptors; hence it is free from interaction with alcohol and benzodiazepines. It does not lead to dependence or withdrawal symptoms with long-term use. It has a delayed onset of action similar to antidepressants.
Reference:
Which of the following drugs stabilizes dopamine release through its action on dopamine receptors?
A. Aripiprazole has been dubbed a dopamine system stabilizer due to its partial agonist action. It acts as an agonist where dopamine is depleted and acts as an antagonist where there is an excess of dopamine, making the availability of dopamine ‘just right’ for normal function.
Which one of the following is NOT a cholinesterase inhibitor?
E. Memantine acts by partially blocking NMDA receptors, thereby preventing cell death related to calcium-mediated excitotoxicity. Donepezil is a non-competitive, reversible acetyl cholinesterase inhibitor (AChI). Rivastigmine is a non-competitive inhibitor for both butyryl cholinesterase and acetyl cholinesterase. Gallantamine is a competitive, reversible inhibitor which modulates nicotinic receptors. Tacrine is a non-competitive, non-selective, reversible inhibitor which acts both centrally and peripherally. It is no longer used because of high hepatotoxicity. Organophosphates are often used in pesticides and have acetyl cholinesterase-inhibiting properties.
Which of the following drugs is NOT metabolized by CYP3A4?
E. Among the antipsychotics, typical antipsychotics are mostly metabolized through CYP2D6. Risperidone is metabolized by CYP2D6. Clozapine and olanzapine are primarily metabolized through CYP1A2, and to a lesser extent, through the CYP 3A4 enzyme system. Olanzapine is also metabolized through the CYP3A4 enzyme system. The other antipsychotics listed in Question 24 are metabolized through the CYP3A4 system.
Select one side-effect of antipsychotics that appears earlier than the others when initiating treatment:
B. Akathisia occurs within hours to days after onset of antipsychotic treatment in most vulnerable cases. Prevalence is thought to be around 25%. It has both a subjective component of inner restlessness and an objective motor restlessness, manifested as constant pacing, shuffling, or inability to stand still. A specific rating scale to measure akathisia is the Barnes Akathisia Rating Scale. It is to be distinguished from psychotic agitation as akathisia has been linked to suicide and violence. Akathisia can also be caused by serotonergic antidepressants that stimulate 5HT2 receptors. A slow-developing form of akathisia, called tardive akathisia, may be particularly difficult to treat. There is also some evidence to say that persistent akathisia (especially the tardive variant) may predict the development of tardive dyskinesia in the future. Dystonic reactions can occur within minutes of administration of injectable antipsychotics in vulnerable individuals. They are less common with the atypical antipsychotics compared to highly potent, typical antipsychotics (prevalence 10%).
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