Hi,
A bit of history first:
I have had PD for many years, my first symptom showed, believe it or
not, in 1946 when I was 23
years old. Of course, I didn't identify the painful cramping of the
toes of my right foot as a
aymptom until many years later after I received the proper diagnosis
of PD. Anyway, I am
interested in your discussion of the dyphasic reaction to levodopa
because I first noticed that I had
a different reaction to medication than others in our support group
way back in the late '70's. My
neurologist at the time told me I was definitely confused because
what I described was impossible.
Then, in 1982 in an issue of Clinical Neuropharmacology , edited by
Dr. Stanley Fahn on the
management of PD, I read for the first time of the DID response.
This is what Dr. Joseph
Jankovic, noted PD research neuro from Baylor University Medical
School in Houston, Texas
wrote speaking of an experiment evidently done by Dr. Manfred D.
Muenter and his colleagues to
determine levodopa therapy:
"...observed two distinct responses: parkinsonism-improvement-
dystonia-improvement-
parkinsonism (I-D-I response) and parkinsonism-dystonia-improvement-
dystonia-parkinsonism
(D-I-D response). The IDI is analogous to the peak-dose dyskinesia
described earlier. The
dystonia usually occurred 20 min. after each dose, lasted 1 to 3 h.
and preceded and followed
improvement without dystonia. It correlated well with high
concentrations of plasma levodopa.
During the peak levels, some patients also experienced postural
hypotension and drowsiness in
addition to the dystonia...with the DID pattern of response the
dystonia occurred approximately
10 min. after the dose of levodopa, lasted only 5 min. and was
followed by a dramatic
improvement for up to 3 -1/2 h. The second phase of dystonia
occurred after this period of
improvement and lasted up to 1 h., followed by baseline parkinsonian
symptoms. This biphasic
dystonia tends to occur in younger parkinsonian patients, and the
second of the two phases
appears to be longer and more severe...In patients with the DID
response, the postsynaptic
sensitivity may be much greater. With higher doses of levodopa, this
neuronal system, which
mediates the dystonic response, develops depolarization block and
dystonia occurs in a biphasic
manner. The IDI and DID responses can be eliminated by giving very
small doses of levodopa at
short intervals, although an increase in the total levodopa dose has
also been proposed."
This excerpt was referring to an experiment dosing 39 PD patients,
only 5 of whom had the DID
response. After years of dealing with this phenomenon I wish I had
some satisfactory answer to
it, but I don't, nor have the neurologists, as far as I know. My
longevity with PD makes me very
sensitive to meds. I only take five 25/100 Sinemet a day + 1 Eldepryl,
, 1 amantadine, one 2.5
bromocriptine. Fortunately I can still function pretty well part of
the day. It's taken me hours to
write this...
BTW, do any of you notice a build-up of Sinemet reaction in the form
of dyskinesia every five
weeks or so? This happens to me and I get almost a whole day of
dyskinesia. It's exhausting!
Riding my stationary bike like mad is my only recourse to wear off
the energy.
Hope this isn't too boring, didn't mean to go on so long. Bev in
southern Calif
