Levodopa availability improves with progression of Parkinson's disease.
BACKGROUND
Previous pharmacokinetic trials with standard levodopa formulations showed a different behaviour of levodopa degradation in plasma of patients with Parkinson's disease (PD) in various stages.


OBJECTIVE
To investigate associations between levodopa plasma levels in relation to the scored intensity of PD.


METHODS
We administered water soluble 100 mg levodopa and 25 mg benserazide to 50 PD patients, taken off medication for at least 12 hours, and assessed the levodopa plasma concentrations during an 180 minutes period under standardised conditions.


RESULTS
The computed area under the curve (AUC) values of levodopa plasma levels were significant higher in advanced PD patients. PD rating scores significantly correlated to the AUC outcomes and the maximum levodopa plasma concentration.


CONCLUSIONS
Levodopa availability improves with progression of PD. This may result from deteriorated peripheral activity of levodopa metabolising enzymes or an increasing enteric dysfunction with subsequent better duodenal levodopa absorption or both.
Woitalla
Dirk
D
Department of Neurology, St. Josef Hospital, Ruhr University Bochum, Gudrunstr. 56, 44791 Bochum, Germany.
Goetze
Oliver
O
Kim
Jeong I
JI
Nikodem
Alice B
AB
Schmidt
Wolfgang E
WE
Przuntek
Horst
H
Müller
Thomas
T
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000978:Antiparkinson Agents / Q000097:blood* / Q000627:therapeutic use; D019540:Area Under Curve; D002851:Chromatography, High Pressure Liquid; D018450:Disease Progression; D005260:Female; D006801:Humans; D007980:Levodopa / Q000097:blood* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000097:blood* / Q000188:drug therapy; D012720:Severity of Illness Index; D013223:Statistics as Topic; D013997:Time Factors
D000978:Antiparkinson Agents; D007980:Levodopa