In my case it doesn't seem to help. The following paper also confirms this.
What is your experience?

http://www.springerlink.com/content/w320115652210q61/
Alessandro Agnoli1, Massimo Casacchia1, Stefano Ruggieri1, Federico Volante1 and Neri Accornero1

(1) 1a Clinica delle Malattie Nervose e Mentali, State University of Rome, Rome, Italy

Received: 27 March 1972
http://www.springerlink.com/content/w320115652210q61/
Summary Tremor is among the parkinsonian symptoms one of the most difficult to control. Even the treatment by l-DOPA does not give satisfactory results. According to recent biochemical hypothesis, a loss of functional balance of cerebral serotonin and histamine seems to be responsible for the symptom. The results obtained by the administration of antihistaminic, antiserotoninic, antiaminic and acetylcholinic drugs were quantitatively compared by using a piezoelectric accelerometer. The antihistaminic drug is found to be very active but unfavourable side effects are present, while the antiaminic drug is not less active, with the advantage of being free of such effects.
Key words Parkinson-Tremor - Tremor in Parkinson - Antiaminic Drugs - l-DOPA