Pharmacology
In this video we can discuss about anti-parkinsonian tracks so let’s start with the definition these are the drugs that have therapeutic effect in parkinsonism now what is parkinsonism what is the reason for parkinsonism parkinsonism will occur if there is an decrease in dopamine which is a neurotransmitter in brain so if there are any decreasing dopamine in
Brain it will use to parkinsonism now how can we treat parkinsonism we can treat parkinsonism by either increasing the release of dopamine or by decreasing the degradation of dopamine so what is parkinsonism in the kiana parkinsonic life symptoms in the is it is an extra pyramidal motor disorder which is characterized by rigidity tremor and hypokinesia with
The secondary manifestation like defective posture and jet and mask like face and siloria dementia may accompany along with these side effects so what will happen if it is left untreated if untreated the symptom symptoms will progress over the several years to end stage disease in which patient is rigid unable to move unable to breathe properly and there
Will be a chest infections and embolism and this is the this is due to the deficiency of dopamine in stratum which control usually this dopamine is the main neurotransmitter which will control the muscle tone and coordinate the movement in the body unable to move in like the breathlessness difficulty in doubt in the law okay now coming to the classification of
Anti-parkinsonium tracks it is mainly classified into direct acting in brain dopaminergic system and direct affecting in brain cholinergic system and the drug affecting in the brain dopaminergic system is again classified into dopamine precursors like liver dopa peripheral decarboxylase inhibitors that is carbidopa and benzerazide dopaminergic agonists like
Bromocriptin propyrinel ropinirole and premipixor mono amino oxygenase b inhibitors like selegelini and raza galini catecholamine orthomedial transferase inhibitors like endacapone and total carbon glutamate or n-methyl d-aspartate receptor agonist like amendarin so these are the drugs which will affect on the dopaminergic system and the drugs which will affect
On brain cholinergic systems are central angie cholinergic like tri hexafinity and procycline and bipolarity and antihistamines which are the drugs which will inhibit the histamine receptors like orphanage and promethacin so this is the classification of anti-parkinsonian drugs so this is the classification now coming to the first drug that is livodop so as we
All know uh the parkinsonism is mainly due to the decreasing dopamine in the brain so it is the a deficiency of dopamine in a brain so we can treat by giving the dopamine acids but problem is the dopamine as such will not process blood-brain barrier so in order to close the blood-brain barrier we have to formulate the dopamine as a protect that is libodopa that’s
Why we are using levodopa so that is the first drug libodopper now what are the actions of livorpa in cns hypokinesia and rigidity will resolve first later tremor as well will result secondary symptoms of posture jain handwriting speech facial expression mood self-care and interesting life are gradually normalized due due to the administration of liver dopa for
A period now coming to the action in cardiovascular system peripherally formed dopamine will leads to tachycardia due to its beta adrenergic receptor action but usually there will not be any rise in dp now in chemotrigger zone dopamine will act as an excitatory transmitter and dopamine formed peripherally green access to the chemo trigger zone without hindrance
And it may elicit the nausea and vomiting now in case of endogenous dopamine act as in pituitary mammothropes to inhibit the prolactin release as well as on somatotropes to increase the growth hormone release so these are the actions of libodopa now coming to the adverse drug reactions of liver dopa at the initiation of therapy the side effect can be minimized by
Starting with low dose and the usual adverse drug reaction at the initiation of therapy are nausea and vomiting postural hypertension cardiac arrhythmia exacerbation of angie angina alteration in the thirst and sensation and after prolongation of after prolonged therapy there are some adverse drug reaction legs like abnormal movement or dyskinesia then behavioral
Effects fluctuation in motor performances so these are the adverse drug reactions of liver dopa now coming to drug interaction periodoxin will increase the peripheral decarboxylation of liver dopa and it will leads to decreasing dopamine uh liver dopa action phenotyas in butyrophenone reverse the therapeutic effect of liver dopa by blocking dopaminergic receptor
So all these are antipsychotic tracts which will block on d2 receptor so effectively would opera will be blocked and postural hypertension may be caused by acting accumulated by a high in the hypertensive so these are the some important drug interactions of liver dog so main uses to for the treatment of uh angie parkinsonism or i use it as an anti-parkinsonism
Trek now coming to next drug that is the peripheral decarboxylase enzyme or enzyme inhibitor like carbidopa and benzerrasis so as we mentioned before uh we are using liver dopa as a prodrug of dopamine in order to close the blood brain barrier but the problem while using liver dopa is dope levodopa may be decarboxylased by this decarboxylase enzyme peripheral
Decarboxylation same before it penetrating into the blade brain barrier so in order to proven this decarboxylation we have to use carbidopa or benzerras which is peripheral decarboxylase inhibitors along with the dopamine in order to prevent the decarboxylation peripheral decarboxylation and thereby it will penetrate the blood-brain barrier and this carbidopan
When sarah said will not penetrate into the blood-brain barrier and do not inhibit the conversion of levodopa to dopamine down their problems uh uh okay so what is the advantages of this peripheral decarboxylase inhibitors so it is usually administered along with the liver dopa thereby we can increase its half-life we can increase the half-life of liver dopa in
The periphery and also it can make more available to close the blood brain barrier and it will reaches its sight of action and thereby it can we can reduce the dose of liver dopa up to one fourth if we are using liver dopamine usa okay now coming to next direct that is dopaminergic again is like bromocriptin so uh this dopamine agonist can act on striatal dopamine
Receptor even in advanced patients who have largely lost the capacity to synthesize store and release dopamine from the liver dopa so that is the dopaminergic agonist now coming to next class of truck that is my ob inhibitor like salicyline monoamino oxygenase inhibitor this is a selective and irreversible mono amino oxygenase b inhibitors so uh the degradation of
Liver dopa dopamine can be prevented thereby it can increases the amount of neurotransmitter like dopamine now what are the adverse drug reactions of ob inhibitors postural hypotension nausea confusion and accumulation of liver dopa induced involuntary movement and psychosis partly metabolized by liver into amphetamine which sometimes cause insomnia and agitation
And celegenin is contraindicated in patient with convulsive disorder so this is the maopi inhibitor now coming to next class of direct that is glutamate or nmda receptor antagonist or dopamine facilitator like amanda so these amandarin are developed as an antiviral drug which is used for the prophylaxis of influenza a2 but it was found serendipitously to benefit
The parkinsonism it will act rapidly but lower efficacy than lipodopa which is equivalent to or higher than the anticholinergic flux now what are the adverse drug reactions of amanda insomnia restlessness confusion nightmare anticholinergic effects and rarely hallucination a characteristic side effect due to the local release of catecholamines is resulting in
Post-capillary vasoconstriction in liver libido rusticularis and edema of angles these are the important adverse drug reactions of amanda now coming to uh centrally acting tricks these are the drugs which will act on cholinergic tricks like triaxial phenidine or benzexol it is usually used it is used only effective in drug-induced parkinsonism are usually this
Drug-induced parkinsonism are caused by the prolonged use of anti-psychotic tracts which will block the dopamine receptor d2 receptor blocking so a chlor promising like drugs typical uh conventional and the psychotic drugs will cause drug induced parkinsonism if it is treated for a long period of time so it will not alter the basic pathology of parkinsonism
A disease progression will be continued it will only provide systematic symptomatic relief and give more most of the patient an additional three to six year of happier and productive life life so that is the uh centrally acting trek or regarding on cholinergic receptor like benzexol so that is all about anti-parkinsonium drugs this is caused by deficiency of
Dopamine so we can treat by either giving dopamine as a precursor or by decreasing the degradation of dopamine and that is all about parkinsonism track hope it is clear thank you for watching this video
Transcribed from video
ANTIPARKINSONIAN DRUGS: Pharmacology: Levodopa: Carbidopa: Selegiline: Amantadine: Benzhexol By AsHiF’s Pharma Classes
