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.
>
>
>
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