Course and Duration of Therapy with Parkinsonian Drugs and Withdrawal Syndromes

Abstract

Current strategies for the treatment of Parkinson's disease (PD) are still mainly based on the use of dopaminergic medications such as L-dihydroxyphenylalanine (L-DOPA) and dopamine agonists to stimulate striatal dopamine receptors. Indeed, therapeutic intervention with these drugs has improved the prognosis of patients with PD over the last 50 years. However, it is still inconclusive as to which medication is the best for the initial treatment of PD and whether these medications have disease-modifying effects in the long clinical course of PD. In addition, long-term treatment with these drugs can cause complications that induce motor and non-motor symptoms, including withdrawal syndrome, in patients with PD. These symptoms are refractory to L-DOPA therapy and dominate the late-stage disability, which features some clinical milestones to the end of the disease. It is important to consider the influences of parkinsonian drug treatments on the clinical course of PD. In this chapter, therapy with parkinsonian drugs and their pharmacological properties, including adverse effects and influence on disease progression, will be discussed in detail.