What is the typical trial period of Sinemet to establish a PD diagnosis? Should improvement be apparent after several days of initiating therapy, or after several months?
If the trial period does not confirm a PD diagnosis, is the Sinemet dose gradually decreased over a period of several days or weeks? If so, are there withdrawal symptoms experienced during this period and what are the most common?
Thank you for any experiences/suggestions in reply to the questions indicated.
Your diagnosis should be made before your Sinemet use
Thank you for responding. Instead of "establish" a diagnosis, "confirm" might have been a more appropriate word. The trial period of Sinemet supposedly "confirms" the clinical diagnosis. My question, therefore, is what is the trial period to "confirm" the clinical "diagnosis"?
As far as I know there is no proscribed length of the “trial” period. The effectiveness of sinemet, or lack thereof, is used to confirm or reject a PD diagnosis.
In the U.K. the doctors advisory group NICE. does not support using a levodopa trial as a diagnostic aid.Even so some doctors continue. DAT scans are also rarely performed
Sinemet (carbidopa/levodopa) is often used as a diagnostic tool for Parkinson's. If you experience symptom relief while taking C/L during a trial period, then it is very likely that you have Parkinson's. Conversely, if you do not experience any symptom relief then you most likely do not.
I am currently in the process of doing this. My instructions were to start with one-half tablet of 25/100 C/L, 3x a day for the first week. Then gradually increase by .5 tablet each week. There is no need to go higher than 3 tablets, 3x a day at week 6. If you are not experiencing any symptom relief, then taking more will not likely provide any benefit, as you probably do not have Parkinson's. If you decide to stop, it is best to slowly decrease the dosage, although it does not have to be as slowly as when increasing the dosage. You can reduce by .5 tablet every 2 or 3 days.
General guidelines for taking C/L are one hour before a meal or two hours after a meal. Daily doses should be a minimum of 3-4 hours apart.
Thank you so very much for your response. My current protocol replicates yours. I gradually titrated (over the course of 7 weeks) to 2 x's 25/100 C/L. Recently, the dosage was increased to 3 x's 25/100 C/L per day. There has been no symptom mitigation. In fact, the rigidity seems even more pronounced. I am supplementing with B-1 (2 g per day) since April.
Therefore, I am pondering stopping the C/L as no benefits have been noted for this period of time. There is no doubt that I have PD! PSP was ruled out by a neuro who specializes in PSP.
Further clarification: The dosage was 2-25//100, two times per day. It has now been increased to three times--for a total of 6 tablets per day.
When it was first suspected I had PD, my neurologist offered the option of trying Sinemet for two weeks. I declined so we never discussed the actual protocol. Fast forward five years when I started on it, I had slowed down significantly. I was prescribed three 25/100 pills a day. I started with two, but the effect was immediate.
Thank you! I hope the effects continue for you.
Our neuro'd protocol was very similar to what PixiePaul describes above. He said four weeks was the normal amount of time (with similar increasing dosages) to measure whether the levodopa (Sinemet) was having a noticeable effect.
Thank you for sharing!
Actually, though, my husband did a second month even higher, and then showed some response. He has an atypical parkinson's. The first month's test proved it wasn't regular Parkinson's, the second month showed he got some relief with a high dose. But we took the dose back down, which is typical--the trial is to see if you respond, but the trial dose isn't necessarily either the med or the dosage the neuro will want you to go on after the test.
I was prescribed c/l on diagnosis and it made me as sick as a dog, after 10 days or so I couldn't work or pretty much move so I stopped. Bradykenesia was bothering me at work so I tried again at a later date, increasing the dosage much more slowly and stuck with it for a month or so, still no effect. Neurologist said I clearly had PD though, gait, stiffness, face, no right arm swing, slight tremor etc. A year or so after that I tried again, this time taking morning dose with domperidone (anti-nausea) and over the weeks increasing it to 2 x 25/100 three times a day and now I have my arm swing back and gait is much faster and more upright. (unfortunately my hands still very slow with bradykenesia)
It's a tricky thing using it as a diagnostic tool. We all want a name for our ailments so we know what we're facing and how to deal with it but I think unless you have something fairly debilitating to the point of stopping you enjoying/working/etc then I wouldn't bother with the c/l at the early stages. Exercise as much as you can, work on retaining those neuro pathways and then when symptoms get bad enough introduce the c/l really slowly increasing.
Thank you! Five years ago I refused the C/L. However, the progression warrants pharmaceutical intervention at this time. The fact that there has been no noticeable effects from the C/L is concerning.
I know just how you feel, I found it frustrating myself. What symptoms do you have that you most want relief from? One thing I meant to add was that I finally had some positive relief from symptoms when I took the c/l away from meals, so I have them at 7, 11 and 3 now. I don't bother with the evening one as I sleep OK now.
I am experimenting with taking the C/L two hours after a meal, instead of one hour. Originally, I was told to take C/L after a full meal. The symptoms that I had hoped would be improved are severe bradykinesia, rigidity, balance, in-coordination and brain fog. The tremor in my right hand is apparent but not as bothersome.
Thank you for your thoughtful reply. I hope you continue to experience positive effects.
Interesting, I hardly have a tremor either. We seem to be a small subset of people who don't have much of a positive reaction to c/l.
Grower and Syncletica
I think you are right Grower, from conversations with others and from my observations I have the impression that people with gait dominant problems rather than tremor dominant don't have as marked a response to C/L. It doesn't seem to give them the profound on offs that some of us have. However it seems to still make enough of a difference to keep taking as you found.
hikoi---i had severe bradykinesia, but no tremor. and i had dramatic results with my first dose of c/l. within the hour, i was like a new person. i have been taking c/l for 16 yrs, and have very little off time - only about 15 min a day. i am taking 1 tablet of 25/100 every 2 hrs, but it is worth it to be able to be myself again.
Thankyou so much for this information. Though what i have noted is true for many there is yet another group it seems. Tell me have you lost your sense of smell? And just curious how many doses do you take in 24 hours?
7 doses total a day. i start at 6 am, last dose at 6 pm. and im in bed by 9 pm. i used to have to take a half tablet during the the night to prevent morning dystonia, but since ive been taking the thiamine, i dont get the dystonia anymore, so i can go the whole night without the c/l. i did lose my sense of smell, but it returned after i started taking mannitol.
i was prescribed 2 tablets of c/l 25/100 and noticed positive results within the hour. however that dose was too high. i had exaggerated movements, so i reduced it to one tablet, and that was the right dosage for me.
Thank you for referencing your experience. Wishing you the best..
I tried it as a diagnostic tool when I first got symptoms three years ago. Did nothing, but made me kinda nauseated. Went right off two weeks later. Still don't take it. Symptoms about the same today. (Take supplements, eat crazy diet)
I guess when my symptoms get worse I will try it again. :o)
Thank you! I hope your symptoms remain stable.
My positive response was within hours but I was also extremely nauseous. It took about 6 months for me to realize I needed to take the extended release version on an empty stomach 3 times a day at least an hour before eating.
I wonder why the extended version is not prescribed as the first choice. I have not been nauseous. However, for the first 7 weeks, I was told to take the C/L after a full meal. Now I am experimenting with the suggestion by Paul above to take the C/L an hour before or 2 hours after eating.
Extended release is not generally favoured and that goes internationally. I think it is harder to monitor, it is variable in its effective time.
my neuro told me the extended release doesnt really work well as extended release, and that i will have alot of off time. he said i could try it if i wanted to. i did, and he was right - alot of off time. the immediate release is so much easier to adjust to what works best for the individual, as far as timing and dosage.
Thank you for taking time to explain!
Thanks, Hikoi!
I'm remembering they said take sinemet with carbohydrates, which I don't eat, so that was probably a big part of my nausea.
Does Sinemet cause anyone else intense yawning? 
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