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thanks jim fr the short but lucid note for us patients haroon On Thu, Jun 11, 2009 at 2:48 PM, Jim Slattery <[log in to unmask]>wrote: > (Levodopa is only one of the PD medications used to treat PD, but if I > include data on all of them, we will be here all week!) > > Levodopa (L-dopa for short) has been used successfully in the treatment for > Parkinson's Disease for over 30 years. It remains the most effective > treatment for Parkinson's Disease. L-dopa is a natural chemical found in > animals and plants. When L-dopa is formulated for drug use, the generic name > levodopa is used. > > In patients with Parkinson's Disease the cells in the brain that produce > dopamine die. Levodopa works by being taken up by the surviving > dopamine-producing cells in the brain, and is converted by these cells into > dopamine. > > People with Parkinson's Disease can't simply take dopamine tablets or > vegetable products containing dopamine (e.g.fava beans) to replace the > missing dopamine, because dopamine taken by mouth cannot get across the > blood/brain barrier, and is used by parts of the body other than the brain, > and can be "pirated". Levodopa on the other hand does get into the brain > and, once there, it converts to dopamine. Levodopa combined with carbidopa > (Sinemet CR, Sinemet) or benserazide (Madopar) is the main treatment for > Parkinson's Disease. > > Combining carbidopa or benserazide with levodopa has several benefits: > *Carbidopa or benzerazide prevent levodopa from being converted to dopamine > outside the brain. > *They allow more levodopa to enter the brain where it is needed. > *They help to reduce or prevent the side effects of dizziness and nausea. > > Nausea and vomiting can be a problem, as they may result in the dose being > ejected. Any bodily process that delays the passage of the medication to the > small intestine may result in a reduced dose, or even a missed dose. > Constipation is another bodily process that can affect passage of the > medication, and prevent absorption within the "half-life" (approx. 30mins) > of the drug. In PWP, constipation can have several causes, such as taking > opiate-containing medication (eg Codein). > > "Wearing Off" - This happens when Parkinson's symptoms begin to recur > before the next scheduled dose of the drug, due to progression of the > disease. When this happens, it is easy to think that the drug is making your > symptoms worse - for a while after you take the next dose, your symptoms can > continue to worsen until the next dose "kicks in". This happens because the > drug takes a while to be absorbed and reach your brain. > > "On-Off" - These are unpredictable fluctuations in response to drug therapy > that may last up to several hours. They are thought to be due to a > combination of levodopa dosage and progression of symptoms. The dopamine > storage cells may lose their capacity to retain the dopamine delivered by > the medication. > > Dopamine is one of the catecholamine group of neurotransmitters, which > includes adrenaline (epinephrine) and noradrenaline (norepinephrine), the > so-called "fight or flight" hormones. In times of stress, the brain can turn > dopamine into these other hormones, thus depleting the store of dopamine. > > Sorry for the long-winded explanation, but it is as short as I can get it, > and still make sense. > Jim > (Dr. James F Slattery, PhD Soc Sc) > ---------------------------------------------------------------------- > To sign-off Parkinsn send a message to: mailto: > [log in to unmask] > In the body of the message put: signoff parkinsn > -- Haroon Basheer Tel USA : 1-917 251 0657 Asima Haroon Tel USA: 1 917 251 0630 ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn