Comprehensive review of rasagiline, a second-generation monoamine oxidase inhibitor, for the treatment of Parkinson's Disease

Abstract

Background: Inhibitors of monoamine oxidase (MAO) with selectivity and specificity for MAO type B (MAO-B) prolong the duration of action of both endogenously and exogenously derived dopamine. Rasagiline [N-propargyl-l(R)-aminoindan] is a second-generation propargylamine pharmacophore that selectively and irreversibly inhibits brain MAO-B and is specifically designed for the treatment of Parkinson's disease (PD). Objective: The aim of this study was to review the pharmacology, tolerability, and clinical efficacy of rasagiline in the treatment of PD. Methods: MEDLINE (1966-April 2007), the Cochrane Database of Systematic Reviews, and International Pharmaceutical Abstracts (1970-April 2007) were searched for original research and review articles published in English. The search terms were monoamine oxidase, neuroprotection, Parkinson disease, propargylamine, rasagiline, and selegiline. The reference lists of articles were also consulted, as was information provided by the manufacturer of rasagiline. Results: Data from 63 clinical and laboratory studies were analyzed. Based on the results from those studies, we concluded that rasagiline PO QD, at the therapeutic dosage range of 0.5 to 1 rag/d, is effective and well tolerated and completely, selectively, and specifically inhibited MAO-B. Pharmacologically, rasagiline was found to be ≤10-fold more potent than selegiline and was not metabolized to amphetamine derivatives. Rasagiline was effective both as monotherapy in early PD and as adjunctive treatment in patients with advancing PD and motor fluctuations. As monotherapy, rasagiline provided modest yet clinically meaningful benefit. A randomized, double-blind, placebo-controlled study found that, after 26 weeks of treatment, the adjusted effect size for total Unified Parkinson's Disease Rating Scale score was –4.20 (95% CI, -5.66 to -2.73) for rasagiline 1 mg/d versus placebo (P < 0.001). Preliminary long-term data from an open-label study suggest a sustained therapeutic advantage when rasagiline is initiated early (before the need for dopaminergic agents) rather than later. In patients with more advanced disease who received treatment with dopaminergic agents, rasagiline and entacapone were associated with reductions of “off” time significantly greater than placebo (-1.18 and -1.2 vs 0.4 hour; both, P ≤ 0.001). Rasagiline was well tolerated in younger (aged <;70 years) and older (aged ≥70 years) patients with early or advanced PD. Pharmacologically, rasagiline has the potential to augment the vasopressor effects of diet-derived tyramine (ie, the “cheese reaction”). However, clinical challenge studies of tyramine have found this unlikely to occur even with ingestion of supraphysiologic amounts of tyramine. In experimental models, rasagiline has been found to have neuroprotective properties that may be independent of MAO-B inhibition. Conclusions: Based on this review, rasagiline has been found to be well tolerated and effective in the treatment of early PD and as adjunctive treatment in motor fluctuations. Whether rasagiline is associated with clinically significant neuroprotection (ie, disease modification) in PD is the subject of ongoing clinical trials.