An update on the use of non-ergot dopamine agonists for the treatment of Parkinson’s disease

ABSTRACT

Introduction

Long-term treatment of Parkinson’s disease (PD) with levodopa is hampered by motor complications related to the inability of residual nigrostriatal neurons to convert levodopa to dopamine (DA) and use it appropriately. This generated a tendency to postpone levodopa, favoring the initial use of DA agonists, which directly stimulate striatal dopaminergic receptors. Use of DA agonists, however, is associated with multiple side effects and their efficacy is limited by suboptimal bioavailability.

Areas covered

This paper reviewed the latest preclinical and clinical findings on the efficacy and adverse effects of non-ergot DA agonists, discussing the present and future of this class of compounds in PD therapy.

Expert opinion

The latest findings confirm the effectiveness of DA agonists as initial treatment or adjunctive therapy to levodopa in advanced PD, but a more conservative approach to their use is emerging, due to the complexity and repercussions of their side effects. As various factors may increase the individual risk to side effects, assessing such risk and calibrating the use of DA agonists accordingly may become extremely important in the clinical management of PD, as well as the availability of new DA agonists with better profiles of safety and efficacy.

KEYWORDS:

• Dopamine agonists
• Parkinson’s disease
• preclinical and clinical findings
• side effects

Article highlights

• Long-term treatment of Parkinson’s disease (PD) with levodopa is hampered by motor complications

• Non-ergot dopamine agonists are extensively used, as standalone treatment in the early phase of PD or as add-on therapy to levodopa in the more advanced stages

• Latest findings confirm the clinical efficacy of dopamine agonists, but a more conservative use is emerging, due to the complexity and repercussions of their side effects

• Various factors may increase the individual vulnerability to dopamine agonists side effects.

• Assessing such risk may become extremely important in the clinical management of PD

• New dopamine agonists with better profiles of safety and efficacy, as well as new formulations granting higher bioavailability are currently being investigated.

This box summarizes key points contained in the article.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This manuscript has not been funded.