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.