Limitations of long term use of antiparkinson drugs.

Effective control of parkinsonian symptoms can be achieved in a substantial number of patients by the judicious use of dopaminergic agents. To a considerable extent these drugs produce optimal therapeutic effects during the first 3-5 years of their use. Subsequently, efficacy diminishes with reemergence of parkinsonian symptoms as well as a number of untoward responses. The nature, frequency and mechanisms underlying the limitations of long term use of presently available anti-parkinson agents are discussed in this presentation.