Effect of levodopa treatment for parkinsonism in welders: A double-blind study.
BACKGROUND
Manganese is known to cause a parkinsonian syndrome similar clinically to Parkinson disease (PD). L-Dopa responsiveness is a hallmark of PD; however, L-dopa's effect on manganese-induced parkinsonism is not well defined.


OBJECTIVE
To access the efficacy and safety of L-dopa therapy in a double-blind, randomized, placebo-controlled trial.


METHODS
Thirteen patients with manganese-induced parkinsonism were evaluated in a cross-over study with a modified Unified PD Rating Scale (UPDRS), timed walk test, tapping, and global clinical impression scores. Adverse reactions were assessed.


RESULTS
There was no significant difference between placebo and L-dopa for any measure: motor UPDRS, 27.4 vs 28.8; walk time, 16.6 seconds vs 17.7 seconds; tapping right hand, 69.5 vs 64.7; and tapping left hand, 66.8 vs 64.4. There were no differences in the global impression scores. Adverse reactions occurred similarly in the two groups, including headaches, drowsiness, and diarrhea.


CONCLUSIONS
L-Dopa therapy is not effective for the management of parkinsonism in welders. L-dopa unresponsiveness may be useful to distinguish manganese-induced parkinsonism from Parkinson disease.
Department of Neurology, The Mount Sinai School of Medicine, New York, NY, USA. william.koller@mssm.edu
William C
WC
Koller
Kelly E
KE
Lyons
William
W
Truly
D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use*; D008297:Male; D020149:Manganese Poisoning / Q000150:complications* / Q000175:diagnosis; D008875:Middle Aged; D010302:Parkinson Disease, Secondary / Q000175:diagnosis / Q000188:drug therapy* / Q000209:etiology; D014896:Welding
D000978:Antiparkinson Agents; D007980:Levodopa