The effect of deprenyl washout in patients with long-standing Parkinson's disease

Deprenyl, an irreversible MAO-B inhibitor, is known to have a symptomatic effect in de novo patients with Parkinson's disease (PD). It has, however, not been studied thoroughly in patients with advanced PD and response fluctuations. This study evaluated the effect of washout of deprenyl in patients with long-standing PD. Eleven PD patients who were on chronic treatment with deprenyl (mean age 57 +/- 8 years, mean disease duration 8.4 +/- 2.9 years), seven with response fluctuations, were enrolled in a double-blind study of a novel MAO-B inhibitor. A deprenyl washout period of one month was required prior to initiation of treatment with the trial drug. Patients were evaluated by Unified Parkinson's Disease Rating scale (UPDRS) before and one month after the washout period. Motor function was quantified by computerized tapping speed and movement time test. Results showed that neither total UPDRS scores (22 +/- 16 vs. 18 +/- 16, respectively) nor tapping speed and movement time changed significantly (4.4 - 0.5 vs. 4.2 +/- 0.3Hz and 159 +/- 45 vs. 161 +/- 40 seconds; p > 0.1, respectively). However, eight patients reported various degrees of subjective deterioration, among them were the seven fluctuating patients. Two patients first began to experience response fluctuations during the washout period. It seems that deprenyl has a symptomatic effect, especially in patients with response fluctuations, and it may postpone the appearance of fluctuations in patients with PD. Attempts to discontinue treatment with deprenyl may aggravate disease symptoms.