Hey guys welcome to pill reaction in this video we will see why levodopa is given in combination with carbidopa and also we’ll see what are the side effects of levodopa if given alone this liver dopa is a inactive form of dopamine is given in parkinson’s disease this is because in parkinson’s disease degeneration of dopaminergic neurons in substantia is seen
Resulting in dopamine deficiency in simple words we can say that there is an imbalance between dopamine and acetylcholine due to this imbalance in neurotransmitters in parkinson’s disease symptoms like tremors slowness of movement speech change flatulence and loss of smell is seen now let’s have a quick reference of levodopa livo dopa is a dopamine precursor
Used in the treatment of idiopathic parkinsonism let’s understand the mode of action of levodopa first point to understand here is dopamine does not cross the blood-brain barrier hence this is the reason of giving libodopa which is a immediate precursor of dopamine now the levodopa crosses the blood-brain barrier and is converted to dopamine by the enzyme dopa
Decarboxylase now this dopamine interacts with the d2 receptors and relieves the symptoms of parkinson’s disease until this everything seems well and good right but the problem is the enzyme dopa decarboxylase is not only present in the blood-brain barrier but it is also present in the periphery hence when we take lyodopa before crossing the blood-bend barrier
It gets metabolized in the periphery itself thereby releasing the dopamine in the periphery we know that dopamine cannot cross the blood-brain barrier hence the dopamine which is formed in the periphery shows no therapeutic activity in the substantia in turn this dopamine is the source of many side effects in the periphery like vomiting and hypotension hence
These are the main areas of liver dopa here the problem is peripheral dopa decarboxylase which is converting all the livodopa into dopamine in the peripheral right hence to overcome this carbidopa is given along with levodopa this carbidopa inhibits the peripheral dopa decarboxylase now if we see the advantages of the combination therapy of livodopa and carbidopa
We can see the increased bioavailability of dopamine in the basal ganglia hence the dose of liver dopa can be reduced by 75 percent and reduction in the incidence of side effects such as nausea and vomiting tachycardia and hypotension and we can see a better patient compliance these are the reason of not giving levodopa alone but it is given in combination with
Carbidopa thank you for watching if you think this video helped you gain knowledge then please consider sharing it let’s learn together for more such pill reaction videos subscribe to our channel and stay tuned
Transcribed from video
Levodopa | ADR | Why Levodopa is given in combination with Carbidopa? By Pill Reaction
