Acute vs chronic effects of l-dopa on bladder function in patients with mild Parkinson disease.

OBJECTIVE: To compare acute and chronic effects of l-dopa on bladder function in levodopa-naive Parkinson disease (PD) patients who had urinary urgency.

METHODS: We evaluated 26 l-dopa-naive PD patients at a university-based PD center with a first urodynamic session with a double examination: in the off treatment condition and 1 hour after acute challenge with carbidopa/l-dopa 50/200 mg; then, a chronic l-dopa monotherapy was administered (mean dose 300 +/- 150 mg). Two months later, patients underwent a second urodynamic session with a single evaluation 1 hour after the acute carbidopa/l-dopa challenge.

RESULTS: The first acute l-dopa challenge significantly worsened bladder overactivity (neurogenic overactive detrusor contractions threshold [NDOC-t; 32% of worsening] and bladder capacity [BC; 22% of worsening]); on the contrary, l-dopa challenge during chronic administration ameliorated the first sensation of bladder filling (FS; 120% of improvement), NDOCT-t (93% improvement), and BC (33% of improvement) vs the values obtained with acute administration. An 86% significant improvement of FS in comparison with the basal value was observed.

CONCLUSIONS: The acute and chronic l-dopa effects may be due to the different synaptic concentrations or to the activation of postsynaptic mechanisms obtained by chronic administration.