We investigated the short-term effects of a single dose of levodopa (L-dopa) on 
micturition function in PD patients with wearing-off phenomenon. Eighteen PD 
patients who had median Hoehn and Yahr scores of 5 during the off phase and 3 
during the on phase were recruited. We carried out urodynamic studies before and 
about 1 hour after the patients had taken 100 mg of L-dopa with 
dopa-decarboxylase inhibitor (DCI). After taking the L-dopa/DCI, urinary urgency 
and urge incontinence aggravated, whereas voiding difficulty was alleviated in 
all 12 patients. When compared to the baseline assessment, urodynamic study 
results after taking 100 mg of L-dopa/DCI showed aggravated detrusor 
hyperreflexia; decreased maximum bladder capacity (P = 0.006); an increased 
maximum Watts Factor value (P = 0.001), reflecting the detrusor power on 
voiding; an increased Abrams-Griffiths number (P = 0.042), reflecting urethral 
obstruction on voiding; decreased residual urine volume (P = 0.025); and 
increased static urethral closure pressure (P = 0.012). One hundred milligrams 
of L-dopa/DCI worsened detrusor hyperreflexia, producing worsened urinary 
urgency and urge incontinence during the storage (bladder-filling) phase. It 
also increased detrusor contractility much more than it did urethral obstruction 
in the voiding phase, producing overall lessening of voiding difficulty and 
improving voiding efficiency in our PD patients with the wearing-off phenomenon.