This is a brief video on antipsychotics, also called neuroleptics, including their mechanisms, their indications, and side effects
This is going to be a brief video on antipsychotics drugs that are also called neuroleptics and prove again there’s an image here that’s an old advertisement for thorazine which is an anti-psychotic a first-generation antipsychotic back when psychosis had a stigma of violent outbursts so let’s start with first generation antipsychotics like thorazine first generation
Antipsychotics are also called typical antipsychotics this group consists of drugs that end in a zine ac i and ii as well as haloperidol the highly potent first generation antipsychotics are haloperidol tri fluo para zine and flu phenazine the medium potency first generation antipsychotics are parfum is een and the low potency first generation antipsychotics are
Chlorpromazine and theo red is een the mechanism of action for these are that they have a high affinity for the d2 dopamine receptor and they antagonize that receptor meaning that they inhibit dopamine from hitting that receptor this in turn leads to an increase in norepinephrine because dopamine and norepinephrine are kind of in balance with each other and high
Nor for nephron increases the concentration of cyclic am p some indications for using first generation antipsychotics are schizophrenia of course specifically the positive symptoms of schizophrenia like the delusions also all the diseases that go under that schizophrenia umbrella including brief psychotic disorder schizophrenia form disorder and also skis though
Affective disorder there’s other psychosis that you would use first generation antipsychotics for delirium tourette’s and huntington’s as well but mainly schizophrenia and other psychoses some side effects of these typical antipsychotics are that they delay cardiac conduction this is a side effect come in to both first and second gen antipsychotics they delay
Cardiac conduction by prolonging the qt interview which puts you at risk for two torsades which can eventually progress to v-tach and then v-fib so that’s that’s a pretty dangerous the first generation antipsychotics also have anticholinergic effects this includes blurred vision constipation dry mouth and urinary retention if you think about a parasympathetic versus
Sympathetic reaction these all align with the sympathetic reaction the fight-or-flight and that makes sense because acetylcholine is the neurotransmitter involved in parasympathetic reactions so if you have anticholinergic effects they’re going to be sympathetic like blurred vision constipation dry mouth urinary retention which are all fight or flight rather than rest
And digest these anticholinergic effects are worse with lower potency antipsychotics so a high potency anti psychotic like haloperidol will have milder anticholinergic effects there’s an inverse relationship between the potency of the anticholinergic effects and the potency of the antipsychotic so haloperidol is a strong antipsychotic a high potent antipsychotic and
It has milder anticholinergic effects these typical antipsychotics also have an antihistamine effect like sedation that’s like typical and like benadryl as well an antihistamine that gets into your brain causes sedation they also have anti alpha 1 receptor effects which is like orthostatic hypertension causes vasodilation and orthostatic hypertension they have some
Endocrine side effects like hypo prolactin ‘ya and a list of other endocrine related side effects that would result from hyperprolactinemia this is caused by the d2 blockade of the tubero infundibular pathway and then there are extra pyramidal symptoms there extrapyramidal symptoms and neuroleptic malignant syndrome we’re going to be talking about those in greater
Detail in the next couple slides so extra pyramidal symptoms these are caused by d2 blockage of the nigrostriatal pathway now these kind of progressed differently depending on the time course within a few hours 2 days you might get an acute dystonic reaction which is sustained muscle contractions you can treat this with diphenhydramine or stripping which is an anti
Muscarinic drug so that’s an acute dystonic reaction it just means muscle contractions that you cannot control your muscles contract and they stay contracted within days two weeks you get a kasya which is restlessness then from weeks to months you get parkinsonian ism which is indistinguishable from idiopathic parkinson’s disease you get the tremor the cogwheel
Rigidity the hypokinesia this can be treated as well with diphenhydramine or ben’s trippi just like the acute dystonic reaction and then in months to years usually six plus months you can get tardive dyskinesia which is a weird hyperkinetic atypical movement of your head trunk or limbs it’s often common around your face called perioral tardive dyskinesia and that’s
Where your tongue your face and your lips kind of make a it’s worth looking up on youtube tardive dyskinesia of the mouth of perioral tardive dyskinesia you make like a repetitive motion where you’re opening your mouth and puckering and grimacing interesting to see but that’s what happens that’s an extra pyramidal side effect after using the typical antipsychotics
For a long time these this tardive dyskinesia can then be reduced or be treated by either switching from a first-generation antipsychotic to a second-generation antipsychotic and if you’re ready on a second-generation antipsychotics specifically switching to clozapine which is a one of this one of the second-generation antipsychotics that’s particularly potent so
This is kind of the time course of the extra pyramidal side effects that are that are all resulting from d2 blockade on the nigrostriatal pathway one mnemonic to help you remember these in order of khem the progress in which they appear are the underlined letters on this slide so adapt ad apt and you can kind of kind of look at that that might help you remember
The progression of the extra pyramidal side effects another major side effect is neuroleptic malignant syndrome neuroleptics of course are another name for antipsychotics so this is a malignant syndrome resulting from using neuroleptics this is an idiosyncratic reaction presenting with confusion vital signs autonomic instability hyperpyrexia or high fever rhabdo
My lysis which causes myoglobin area renal failure and cardiovascular collapse so it’s pretty urgent mnemonic here is fever so of course you present with fever you present with encephalopathy you present with unstable vitals high blood pressure high heart rate your enzymes increase things aren’t looking in the blood and you have rigidity of the muscles this
Neuroleptic malignant syndrome often presents with or often presents similarly to malignant hyperthermia and it might be worth looking up a table to help you differentiate between those nonetheless it’s important to distinguish that you have nms neuroleptic malignant syndrome because as specific treatment of dantrolene so again don’t confuse that with malignant
Hyperthermia they often look the same they both have high fevers and they the drugs that bring them on or a little different it’s also commonly confused with serotonin syndrome – which also has the high fever and some of the some of the autonomic instabilities so it’s worth being able to differentiate between those and lastly we’re going to talk about the atypical or
Second-generation antipsychotics these are drugs that either end in a peon i’d own and then there’s the irregular every prep result so here’s the list of them you can read through a sin opinion clozapine olanzapine they all end in a peon i’d own or azole a peon i don’t or asel and if we go back to the first generation antipsychotics we can be reminded that those
Were haloperidol and ending in a zine so contrast a zine from the first generation antipsychotics with the second generation antipsychotics which end in 18 and i don’t so a zi and e is first gen api and e is second gen so there’s your list mechanism of action here that they have weaker dopamine antagonism but they’re also agonists of serotonin specifically the
5h t – a receptor indications here are schizophrenia and they’ve been shown to work for both positive and negative symptoms side effects here are delayed cardiac conduction as we said last time for long qt risk of torsades which can progress to v-tach in v-fib there’s less anticholinergic and eps effects here so that’s why i explained those earlier you also have
Metabolic syndrome here as a side effect which is your typical weight gain diabetes high lipid count and those are specific to the aps – the ones that ended an ap ime a granulocyte ptosis is a serious side effect of clozapine and it’s kind of a trade off class beam is probably the most potent antipsychotic the the most effective at reducing psychosis but it does have
A serious side effect of agranulocytosis so you constantly have to be doing blood counts and looking at the leucocyte level looking at neutrophils in particular because if neutrophils drop that’s a sign of a granulosa ptosis very serious side effect of a drug that’s otherwise very useful so high risk high reward for clozapine and lastly you also see hyperprolactinemia with risperidone
Transcribed from video
Antipsychotics (neuroleptics) By MedLecturesMadeEasy
