Okay you guys my presentation is on carbidopa and levodopa that was a drug that our group was assigned and for absorption it’s very well absorbed from the gi tract and after taking it orally forty to seventy percent is absorbed for its peak plasma time if it you’re taking an immediate release then it’s gonna be half an hour and if you’re taking an extended-release
Tablet then it’s gonna be two hours and the absorption is decreased when it’s taken with food so that’s just one thing that’s important to let people know when they’re taking this med and for distribution carbidopa is widely distributed and the body tissues except for in the central nervous system and the reason that it’s paired with lava dopa is because it helps
Break prevent the breakdown of levodopa long enough for it to distribute across the blood-brain barrier and then levodopa can be distributed into breast milk and then distribution is determined by the rate of levodopa transport from the gut of the blood and from the blood to the brain for metabolism carbidopa is not very metabolized in the body because it’s whole
Job is to prevent the metabolism of levodopa and the periphery and to keep it in its precursor state so it can cross the blood-brain barrier and then levodopa is highly metabolized in the periphery by dopamine decarboxylase and catechol o methyl transferase and then levodopa is carried across the blood-brain barrier by an amino acid transporter and gets turned
Into dopamine inside the brain by dopa decarboxylase and then this is a video that we found that just kind of shows that let’s see if it pulls up and then if you don’t want to watch the video on my screen i also have the powerpoint me just so that you can watch them in this lecture we were gonna cover the pharmacology of drugs for parkinson’s disease so let’s
Get it right into it parkinson’s disease is a neurological disorder that results in a progressive loss of coordination and movement now the neurons responsible for coordinating movement are located in a part of the brain called striatum which receives information from two major sources the neocortex any region known as a substantial the cortex relays is sensory
Information as well as plans for future action while the substantia sends dopamine that helps to coordinate all of the inputs now parkinson’s disease develops when the neurons connecting the substantial to that video that you’re not more into it it’s kind of long but it explains all about that drug so that’s a really good one okay so moving on closes for excretion
And the primary excretion for this drug is gonna be renal and done by the kidneys and then 30% is excreted unchanged by the kidneys within 24 hours and then carbidopa increases amount of levodopa it excreted by 6% for pharmacodynamics and mechanism of action levodopa it’s converted to dopamine in the central nervous system where it is used as a neurotransmitter and
Then carbidopa is given in conjunction with levodopa in this pair because it inhibits the enzyme dakar box d carboxylase which i talked about earlier that breaks down and destroys levodopa peripherally so that’s why it can stay in the system longer and then in addition carbidopa helps prevent the premature conversion of levodopa to dopamine in the stream which
Allows more of the levodopa to cross the blood-brain barrier which results in a higher dose in higher dopamine concentrations in the brain adverse effects of this drug is gonna be nausea vomiting dizziness if they have trouble sleeping experience anorexia lightheadedness headache and then or saliva urine and sweat it may turn dark in color and then it may cause
Worsening of tremors hallucinations or depression for special considerations there aren’t usually any problems taking carbidopa or levodopa with meals but some people have decreased absorption have taken on full on a stomach full of protein so kind of how i talked about earlier taking it with food could alter its absorption and if taking for advanced parkinson’s
It is recommended to take it 30 to 60 minutes before meals for the best absorption and then here are references
Transcribed from video
Carbidopa/Levodopa Presentation By Emma Fong
