📌𝐅𝐨𝐥𝐥𝐨𝐰 𝐨𝐧 𝐈𝐧𝐬𝐭𝐚𝐠𝐫𝐚𝐦:-
Now whenever you are using these particular drugs for a higher dose right whenever you are using this particularly liver dopa at a higher dose there is result of an abnormal cori for moments okay so whenever you are using this particular levodopa at a high dose remember there is an adverse effects which are called as the abnormal cori for moments right abnormal cori
For moments abnormal coil for moments of limbs and this abnormal cori for moments this can be also called as this kind easier right these are also called as this kind easier so this abnormal cori for moments they are not only seen in the limbs now apart from the names this abnormal cori for moments they are seen even within the trunk and this abnormal cori for
Moments they are seen even or the tangle right there seem even over the tongue so this can occur with prolonged high-dose treatment of your levodopa but carbidopa can prevent this honor phenomenon but carbidopa does not prevent or does not decrease this koree form movements remember this point there is a very very important point on a phenomenon can be reduced by
Carbon oppa but this abnormal cori for moments they cannot be reduced by this carbidopa alright now how is this effect response then this particular adverse effects they respond to amantadine and possibly leave it a resettable right so this abnormal cori for moments they respond to two drugs one is amount and the other drug that is leavitt error system so these
Two drugs they will reduce this abnormal cori for moments right and another important adverse effect with this levodopa is levodopa especially in elderly individuals this can cause hallucinations right the other important adverse effects are in elderly patients hallucinations not only hallucinations the presence of vivid dreams but the presence of the vivid dreams
This is these are certain abnormal adverse effects with the levodopa elderly individuals and not only that in elderly individuals they this levodopa can also cause even the sleep disturbance and even psychosis right even psychosis so that is the reason why you remember these points right you remember these points this levodopa it is contraindicated in patients
Who ever are having psychosis right these are contraindicated in whoever are having psychosis all right now these behavioral disturbances they are also not prevented by carbidopa right they are not prevented by carbidopa now what you should do right levodopa induced psychosis the drugs what we use is clozapine and as well as quit yappin right so levodopa induced
Psychosis what we use is we use clozapine and as well as the quit yappin right as well as the quit yappin so these are the two drugs which are used in patients with the levodopa induced psychosis right and the another important thing is this particularly would open the another important adverse effects what you should remember is this will cause mid riis’s that
Is the dilatation of the pupil because it will pass mid reassess this levodopa it is contraindicated in angle closure glaucoma right this is contraindicated in angle closure glaucoma right next i have said you one very important point about the dopa decarboxylase what is the vitamin which is acting as a cofactor for this particular dopa decarboxylase this is
Your pyridoxine so pine dachshund is the cofactor for the dopa decarboxylase so a very important precaution what you should remember is the whitening complexes containing pyridoxine they will decrease the effectiveness of the levodopa because if pyridoxine is given pi rocks will act as a cofactor for dopa decarboxylase and this dopa decarboxylase we convert
Levodopa to the dopamine and thereby the effect of this levodopa will be reduced so remember pyridoxine containing vitamin complexes should not be given whenever you are giving the levodopa to the patient right so pyridoxine containing vitamin complexes should not be given why because if you give pyridoxine containing complexes this file toxin containing vitamin
Complexes they will convert levodopa to dopamine in the periphery itself not allowing the levodopa in the enough quantity to cross the blood-brain barrier so whenever you are giving this vitamin complex containing pyridoxine this results in decreasing levodopa in the center that is within the blood-brain barrier right next coming to this particularly word opa
Whenever you are stopping this particular drug you should never stop these drugs abruptly right you should never stop these drugs abruptly the abrupt withdrawal right abrupt withdrawal remember abrupt withdrawal of this particular drug this will precipitate a syndrome which is called as neuroleptic malignant syndrome you like this will precipitate a syndrome
Which is called neuroleptic malignant syndrome all right now another important thing is levodopa that should be given carefully in patients with the active peptic ulcers and even in patients with the malignant melanoma why it has to be given carefully in patients with the active peptic ulcer is this levodopa it has increased risk of bleeding and why it has to be
Given carefully in patients with the malignant melanoma is levodopa it is a precursor for the melanin so when you are giving this levodopa it will increase the melanin levels in patients with the malignant melanoma so in malignant melanoma and as well as in patients with active peptic ulcers this levodopa it has to be given carefully all right so let me summarize
About the entire levodopa now the dopamine precursors are the levodopa dopamine as such it cannot cross the blood-brain barrier but the precursors of the dopamine that is levodopa this can cross the blood-brain barrier but what is happening is this levodopa in the presence of enzyme dopa decarboxylase is converted into dopamine so the dopamine which is formed
In the periphery it is having and disadvantages because of two important problems number one the dopamine which is formed in the periphery cannot cross the blood-brain barrier and the dopamine which is formed in the periphery will cause postural hypotension or demian and as well as nausea and as well as vomiting now for the formation of the dopamine we require
Dopa decarboxylase and the cofactor for that dope a decarboxylase is pyridoxine so now what we do is we give the levodopa along with dopa decarboxylase inhibitors now what are these dopa decarboxylase inhibitors they include the carbidopa and as well as benci reside these are the dopa decarboxylase inhibitors now whenever you use this combination that is levodopa
Plus carbidopa these combinations will reduce all the symptoms of parkinsonism except for the tremors right tremors they are not reduced where much effectively with this combination so that will reduce rigidity and as well as the brady kinesia or akinesia in these patients with the parkinsonism now this particular levodopa whenever you are using in a long term
This will cause the wearing of effect and that is what is called as on-off phenomenon the word on means there are no symptoms that is the effect of levodopa is there the word off means there is full-blown symptoms that will be in a form that there is no treatment given at all now why is this particular wearing of effect or why is this on-and-off phenomenon this
That is mainly because of the short t half of levodopa which is nearly around one to two hours now how can you reduce this on-and-off phenomenon is this on-and-off phenomenon can be reduced by giving the carbidopa along with levodopa and you see the another important adverse effect the dopamine which is formed in the periphery it is causing nausea and as well
As vomiting by stimulating the chemo trigger zone so this particular nausea and vomiting which is formed which is occurring because of the dopamine which is formed in the periphery that can be reduced only by domperidone not by the metoclopramide right not by the metoclopramide all right next now this particularly bored oppa when you are giving this with high
Dose for long term this can cause the adverse effects like abnormal pora for moments in the limbs in the trunk and as well as the tongue and this abnormal cori for moments they are called as this kind easier and this abnormal cori for moments they cannot be reduced by giving carbidopa what we have used for reducing the on/off phenomenon so what are those drugs
Which will reduce this abnormal cori for moments is your amantadine and as well as limit eres attempt the other important adverse effects particularly in elderly patients with the levodopa is that can cause hallucinations vivid dreams sleep disturbance and as well as psychosis and levodopa induced psychosis that can be reduced by the clozapine and as well as the
Whittier thing and another important point what you should remember is whenever you are giving your dopa levodopa it should never be stopped abruptly right he would opa it should never be stopped abruptly abrupt withdrawal of this particularly photo part can cause what is called as neuroleptic malignant syndrome and this levodopa it should be given with utmost care
In patients with the peptic ulcers and as well as malignant melanoma because in peptic ulcers there is risk of bleeding and your liver dopa is a precursor for melanin so it will increase the melanin production in patients with the malignant melanoma now let me discuss all the adverse effects of levodopa and what is the mechanism of those adverse effects and what
Is the treatment what we give for that particular adverse effects now you take the adverse effects that is nausea and as well as vomiting nausea and vomiting that is due to mainly the stimulation of the chemo trigger zone and how do you reduce this nausea and vomiting you will reduce this nausea and vomiting by giving carbidopa right by giving carbidopa and the
Another important adverse effect is the postural hypotension and this postural hypotension is mainly because of the dopamine receptor stimulation and which particular dopamine it is mainly b1 receptor stimulation and this postural hypotension which is occurring due to d1 receptor stimulation this is also reduced by carbon opa and another important adverse effect
Is the athenaeus the arrhenius which are caused by levodopa that is mainly because of the beta 1 stimulation that is beta 1 receptor stimulation and even this are the mirrors which are caused by the stimulation of the beta 1 receptors they are also reduced by carbon opa then another important adverse effect is hypertension and hypertension with this levodopa
Is mainly because of stimulation of the alpha one receptors and how we you reduce this this is also reduced by carbon opa and likely this occurs when combined with mono or minor oxidase inhibitors next the other important adverse effects with the levodopa is mid riis’s that is dilatation of the pupil and why is this material is occurring the mechanism is due to
The stimulation of the alpha-1 receptors so that is the reason why remember this levodopa it is contraindicated in angle closure glaucoma right so the under important eye adverse effect is this kind easier why is this this kind easier this kind easier is mainly because of increase in the activity of dopamine within the brain and remember this particular disc i
Knees here is not reduced by carbon apart this will be reduced by giving amantadine or the limited acetyl next is levodopa induced psychosis that is psychotic symptoms and why is this psychotic symptoms what is the mechanism the mechanism is increase in the activity of dopamine within the brain and even these psychotic symptoms they are not reduced by your
Carbidopa so you have to use clozapine or pity opinion to reduce this levodopa induced psychosis so these are the entire list of adverse effects which is caused by levodopa the mechanisms causing that particular adverse effects and how do you treat that particular adverse effects which are caused by your levodopa so this completely completes the dopamine precursors
Transcribed from video
Dopamine precursors in Parkinson's Disease ( Part 4 ) – CNS Pharmacology By Dr.G Bhanu Prakash Animated Medical Videos