>>Cathy Bradley/Mary G. wrote:
>>Please explain the difference between Sinemet and
>>Sinemet CR<<
Hi CB/MG:
Levodopa is universally recognized by researchers as the
most effective treatment for PD. In order to inhibit the
metabolism of the levodopa outside of the brain, carbidopa is
added. This medication is available as Sinemet in three
ratios: 25/100 (carbidopa/levodopa), 25/250 & 10/100. At
least 75 mg of carbidopa per day is necessary to prevent
metabolism of levodopa outside the brain. If a patient is
being treated with Sinemet and still experiences nausea,
vomiting or light-headedness, additional carbidopa alone may
be necessary.
As the years go by the effects of levodopa in about 50%
of the patient population decline, leading to dyskinesias
(involuntary movements) and dystonia (cramps). If a patient
doesn't get a good response from Sinemet, Drs. usually
combine Sinemet with Sinemet CR, a sustained release
formulation of Sinemet. Sinemet CR gradually releases the
dosage in the stomach which leads to a slower increase in
blood levels, pro-longing the medication and smooths out the
response, reducing the dyskinesias and dystonia.
Other ways of dealing with the side-effects is to change
the interval between dosage, or the timing and size of meals
to increase absorption.
The general consensus of Drs. today [things change] is
that Sinemet CR (25/100 or 50/200) should be given to the
new patient twice daily. If the delay in the onset of
medication (usually 30 minutes to 90 minutes) is a problem,
Sinemet 25/100 can be given with the a.m. dose for a "kick
start." When the patient requires more than 500 to 800 mg
of levodopa daily, most Drs. then add a dopamine agonist
(Parlodel or Permax) .
Many Drs. and patients prefer to begin treatment with
regular Sinemet . . . if their response is okay . . . the cost is
much less.
Last, but not least, researchers have determined that
liquid carbidopa/levodopa improves the effects of the
medication and reduces the motor fluctuations associated
with peak-dose and off-dose periods. The liquid form is
ingested more rapidly and at higher levels. CATCH 22 :
liquid levodopa is not available. Patients can create their
own by crushing or dissolving regular Sinemet tablets in
water. See, Neurology, vol.47, pp. 1493-1495, December
1996.
Good luck. Stephan 52/6
