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Tom Berdine(or anyone): Is there info available on the beta-CIT radioactive dye and SPECT camera. Can this be used to diagnose PD or is it just helpful in assessing dopamine uptake? Thanks for any help. ----- Original Message ----- From: "tOM bERDINE" <[log in to unmask]> To: <[log in to unmask]> Sent: Saturday, November 23, 2002 2:06 AM Subject: Wearing-Off Effects > The levodopa response duration decreases over time, and many patients > eventually develop wearing-off fluctuations. Wearing off occurs during > the day, characterized by a gradual return of parkinsonian symptoms > before the next dose takes effect, usually one to three hours after the > last dose. Initially, a practical approach would be to give smaller and > more frequent levodopa doses. However, at some point this will no longer > be effective. Use of Sinemet CR can be helpful in reducing clinical > fluctuations because levodopa is slowly released from a special matrix, > producing a more sustained clinical effect. > > Adding a dopamine agonist such as bromocriptine or pergolide in > combination with levodopa can help improve wearing-off effects. These > agents should be initiated at subtherapeutic dosages and then very > gradually increased over a period of weeks to therapeutic doses. This > gradual buildup will help reduce adverse effects such as nausea, > hallucinations, hypotension, and sedation. Bromocriptine can be > initiated at 1.25 mg twice daily and then gradually increased, according > to response, to a usual dose of 10-25 mg daily (some require 50-75 mg > daily). Pergolide can be initiated at a dose of 0.05 mg daily and then > can be titrated slowly over a period of weeks to a usual dose of 2-3 mg > (5 mg daily is the maximum). As the dose of the dopamine agonist is > increased, the levodopa dose is usually lowered to reduce dopaminergic > toxicity. > > Another treatment option is amantadine, which can prolong the action of > levodopa and produce some mild improvement in wearing-off effects. > However, amantadine can increase the risk of cognitive impairment in the > elderly, and dosages should be adjusted in patients with impaired renal > function. Initially, amantadine can be given at a dose of 100 mg daily > for one to two weeks before attempting to increase the dose to 100 mg > b.i.d. Doses greater than 200 mg daily are usually not recommended in > the elderly. > > Selegiline is another alternative. Selegiline increases the duration of > levodopa effects by preventing its breakdown, and it has been used > successfully to improve wearing-off effects.3,23 When selegiline is > added to levodopa, it should be started at a low dose and slowly > increased (5-10 mg per day is usually effective) to minimize side > effects.1 The addition of selegiline can exacerbate the side effects of > levodopa and, consequently, a reduction of the levodopa dose by 10%-30% > is usually necessary. The psychiatric side effects of selegiline may not > be tolerated by the elderly. > > For those patients who develop severe wearing-off fluctuations that do > not respond to the above measures, the use of liquid carbidopa/levodopa > is another option. One study showed benefits when this solution was > taken at regular intervals.24 Preparing a carbidopa/levodopa solution is > relatively easy and inexpensive, but the product must be prepared on a > daily basis since it is stable for only 24 hours.20 Use of this solution > sidesteps problems with gastric emptying because it does not need to be > digested before being emptied into the small intestine. Another > advantage to the solution is that it provides more flexibility in > titrating the levodopa dose. The solution can be prepared by grinding up > 10 tablets of carbidopa 25 mg/levodopa 100 mg along with 2g of ascorbic > acid, and adding it to 1 liter of tap water to produce a solution of 1 > mg/mL levodopa, 0.25 mg/mL carbidopa, and 2 mg/mL ascorbic acid. The > ascorbic acid helps to prevent the oxidation of levodopa.24 Some > clinicians recommend dissolving the tablets in Tang fruit drink as a way > to add ascorbic acid to the solution.25 The solution must be shaken well > before use. The presence of black particles indicates that levodopa has > broken down, and a solution with this type of precipitate should be > discarded. > > > > --- > Outgoing mail is certified Virus Free. > Checked by AVG anti-virus system (http://www.grisoft.com). > Version: 6.0.408 / Virus Database: 230 - Release Date: 10/24/2002 > > > ---------------------------------------------------------------------- > To sign-off Parkinsn send a message to: mailto:[log in to unmask] > In the body of the message put: signoff parkinsn ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn