Ropinirole in the treatment of levodopa-induced motor fluctuations in patients with Parkinson's disease

Switching from bromocriptine to ropinirole in patients with advanced Parkinson's disease: open label pilot responses to three different dose-ratios

Newly introduced dopamine agonists, such as ropinirole, may offer advantages compared to such older drugs as bromocriptine in patients with advanced Parkinson's disease (PD) with response oscillations or waning efficacy. Dose equivalence of these two drugs, however, has not been well established, which may complicate switching in clinical practice. In 23 such patients with advanced PD no longer satisfactorily responsive to prolonged bromocriptine therapy (mean dose: 18.9 +/- 6.5 mg/d), we prospectively switched the medication to ropinirole administered at three different dose-ratios (5:1, 3:1, and 2:1), increased at monthly intervals. Selegiline remained unmodified in all 17 patients receiving this medication. A dose-ratio of bromocriptine to ropinirole of close to 2:1 (1.87; mean ropinirole dose: 10.1 +/- 2.5 mg/d) was the only dose that significantly reduced mean motor Unified Parkinson's Disease Rating Scale (UPDRS) scores ( p = 0.030, analysis of variance). Individually considered, however, four patients (21%) scored worse even at this dose-ratio when compared to baseline assessment on bromocriptine. "Off" time was reduced by 57.3% in fluctuating patients, and the dyskinesia score decreased by 53.8%, although the changes were not statistically significant. Higher bromocriptine to ropinirole dose ratios (i.e., 5:1 and 3:1) resulted in "off"-time increases in half of the patients with fluctuations, and two previously stable patients developed a wearing-off effect and one other patient experienced off-time dystonia. One patient developed dose-dependent dopaminomimetic psychotic symptoms with ropinirole. In conclusion, "off"-time motor scores and possibly "off"-time duration, and severity of dyskinesias in patients with advanced PD with prolonged bromocriptine therapy may improve in a majority of cases by switching to ropinirole, provided that the latter drug is administered at a dose ratio of 2:1 compared to bromocriptine. Higher dose ratios are often ineffective or may even cause a clinical worsening of symptoms in some patients.

Levodopa-induced drowsiness in healthy volunteers: results of a choice reaction time test combined with a subjective evaluation of sedation

The aim of the present study was to assess levodopa (L-Dopa)-induced drowsiness in healthy volunteers using two parameters: choice reaction time and a subjective rating of sedation. Sixteen subjects participated in a randomized, double-blinded, crossover study. A single dose of 200 mg L-Dopa or placebo was administered at 9:00 AM. To limit peripheral side effects connected with L-Dopa, subjects were treated with 20 mg domperidone three times daily. Subjective rating of sedation consisted of visual analogue scale. Reaction time was measured by means of responses to two light-emitting diodes. The illumination of one of these diodes constituted the imperative signal. Manual responses were performed on two buttons located under the right and left index fingers. Results demonstrated a positive correlation between sedation level and reaction time (r = 0.70, p = 0.0026). Adverse events of L-Dopa were nausea (four cases) and excitation (one case). Subjects who did not develop adverse events were faster under L-Dopa than under placebo (p = 0.02), whereas subjects who had nausea or excitation were slower. A single dose of L-Dopa either deteriorated or improved choice reaction time in healthy volunteers according to whether it was sedative and whether it generated disruptive adverse events.

Sleep laboratory studies in periodic limb movement disorder (PLMD) patients as compared with normals and acute effects of ropinirole

Periodic limb movement disorder (PLMD) occurs in a variety of sleep disorders and can cause insomnia as well as hypersomnia with daytime somnolence. The aim of this study was to investigate 12 untreated PLMD patients as compared with 12 normal controls and to measure the acute effects of 0.5 mg ropinirole (Requip((R))) - a non-ergoline dopamine agonist - as compared with placebo. In three nights (adaptation, placebo, ropinirole night) objective and subjective sleep and awakening quality were evaluated. In the target variable 'periodic leg movements per hour of sleep' (PLM/(hTST)) PLMD patients showed an increased value of 42/h (normal 0-5/h) with a greater number of arousals due to periodic leg movements (PLM) in sleep. They further demonstrated an increased number of awakenings, sleep stage S1, S4, stage shifts and decreased S2, but there were no significant differences concerning total sleep time, sleep efficiency (SE), subjective sleep quality and morning measures of mood, drive and drowsiness. However, measures of attention variability, numerical memory, fine motor activity and reaction time performance were impaired. Ropinirole 0.5 mg was shown to significantly improve the index PLM/(hTST) by 64% and arousals due to PLM, increase spontaneous arousals, REM-latency, stage 2 and stage shifts and decrease SREM. In the morning attention variability was attenuated and numerical memory augmented. Thus, ropinirole improved some sleep architecture and early morning measures of performance but specifically all PLM variables, which suggests a dopaminergic pathogenesis in PLMD. Copyright 2001 John Wiley & Sons, Ltd.

Ropinirole for levodopa-induced complications in Parkinson's disease

BACKGROUND

Long-term levodopa therapy for Parkinson's disease is complicated by the development of motor fluctuations and abnormal involuntary movements. One approach is to add a dopamine agonist at this stage of the disease to reduce the time the patient spends immobile or off and to reduce the dose of levodopa in the hope of reducing such problems in the future.

OBJECTIVES

To compare the efficacy and safety of adjuvant ropinirole therapy versus placebo in patients with Parkinson's disease already established on levodopa therapy and suffering from motor complications.

SEARCH STRATEGY

Electronic searches of MEDLINE, EMBASE and the Cochrane Controlled Trials Register. Handsearching of the neurology literature as part of the Cochrane Movement Disorders Group's strategy. Examination of the reference lists of identified studies and other reviews. Contact with SmithKline Beecham.

SELECTION CRITERIA

Randomised controlled trials of ropinirole versus placebo in patients with a clinical diagnosis of idiopathic Parkinson's disease and long-term complications of levodopa therapy.

DATA COLLECTION AND ANALYSIS

Data was abstracted independently by the authors and differences settled by discussion. The outcome measures used included Parkinson's disease rating scales, levodopa dosage, 'off' time measurements and the frequency of withdrawals and adverse events.

MAIN RESULTS

Three double-blind, parallel group, randomised, controlled trials have been conducted on 263 patients. The two phase II studies were relatively small, were conducted over the short term (12 weeks), and used relatively low doses of ropinirole (mean administered doses 3.3 and 3.5 mg/d) in a twice daily regime. In view of this clinical heterogeneity and some statistical heterogeneity, the results of these trials have not been included in a meta-analysis. The conclusions of this review are based on the evidence from a single phase III study which was medium term (26 weeks) and used ropinirole doses in line with the current UK licensed maximum in a thrice daily regime. In view of difficulties in assessing changes in off time in ~~ Leiberman 98~~, caused by the initial imbalance between the arms of the trial, it is unsafe to draw any firm conclusion about the effect of ropinirole on off time. However, as an adverse event, dyskinesia was significantly increased in those who received ropinirole (~~ Leiberman 98~~; odds ratio 2.90; 1.36, 6.19 95% CI; Table 8). Measurements of motor impairments and disability were poor in this study with incomplete information available. Levodopa dose could be reduced in ~~ Leiberman 98~~ with a significantly larger reduction on ropinirole than on placebo (weighted mean difference 180 mg/d; 106, 253 95% CI; Table 2). No significant differences in the frequency of adverse event reports were noted between ropinirole and placebo apart from the increase in dyskinesia with ropinirole. There was a trend towards fewer withdrawals from ropinirole in ~~ Leiberman 98~~ but this did not reach statistical significance.

REVIEWER'S CONCLUSIONS

Ropinirole therapy can reduce levodopa dose but at the expense of increased dyskinetic adverse events. No clear effect on off time reduction was found but this may have been due to the under-powering of the single evaluable trial. Inadequate data on motor impairments and disability was collected to assess these outcomes. These conclusions apply to short and medium term treatment, up to 26 weeks. Further longer term trials are required, with measurements of effectiveness, and also studies to compare the newer with the older dopamine agonists.

Economic and health-related quality of life considerations of new therapies in Parkinson's disease

The progressive disability of Parkinson's disease results in substantial burdens for patients, their families and society in terms of increased health resource use, poorer quality of life, caregiver burden, disrupted family relationships, decreases in social and leisure activities, deteriorating emotional well-being, and direct and indirect costs of illness. Health-related quality of life (HR-QOL) measures have been used successfully in cross-sectional studies to identify and characterise these burdens; however, there is not yet substantial evidence that these instruments will be responsive to changes in patients over time and that the results will provide patients and health professionals with clinically meaningful information useful in making decisions about treatment strategies. The few studies documenting direct and indirect costs indicate increased use of ancillary health and community services, significant adaptations in home and transportation, increased use of mobility and self-care aids, and lack of access to appropriate healthcare providers. Patients with Parkinson's disease incur higher hospital expenses, have increased number of prescriptions, and experience earnings loss; the latter also applies to family caregivers. The choice, intensity and timing of therapy are determined by a variety of factors: presenting symptoms, age, employment status, comorbidity, cognitive impairment and level of functional impairment. Choices must be individually tailored to a patient's physical and personal needs. To be useful for patients with Parkinson's disease in clinical practice, clinicians should be able to use HR-QOL measures to identify appropriate medical interventions or socio-behavioural modifications to modify the HR-QOL deficits. However, while the interplay of interventions and clinical outcomes are often well understood, the effects of interventions on HR-QOL outcomes have not been studied extensively. Little research has been done that explicitly links the signs and symptoms of Parkinson's disease to the HR-QOL outcomes. The only Parkinson's disease cost-effectiveness study as yet performed indicated higher costs for patients receiving pramipexole than for those not taking the drug, but additional quality life-years were gained. Longer term effectiveness of many treatment strategies, and the usefulness of HR-QOL instruments to assess these treatments for individual patients over time, are critical areas for future research.

Ropinirole: a review of its use in the management of Parkinson's disease

Ropinirole, a non-ergoline dopamine agonist, has selective affinity for dopamine D2-like receptors and little or no affinity for non-dopaminergic brain receptors. Ropinirole is indicated as adjunct therapy to levodopa in patients with advanced Parkinson's disease. It is also indicated, and recent clinical trials have focused on its use, as monotherapy in patients with early Parkinson's disease. In the symptomatic treatment of early Parkinson's disease ropinirole monotherapy was significantly more effective than placebo in 2 multicentre, randomised, double-blind trials of 3 to 12 months duration as assessed by the Unified Parkinson's Disease Rating Scale (UPDRS) motor scores and Clinical Global Impression/Clinical Global Evaluation Scales. In a similarly designed 3-year comparative study with bromocriptine, ropinirole recipients showed a significant improvement in UPDRS- activities of daily living (ADL) scores; however, motor scores were similar between the 2 groups. Ropinirole and levodopa treatments were similar in efficacy as measured by UPDRS ADL scores, although ropinirole recipients showed significantly less improvement on UPDRS motor scores at the 5-year study end-point in a multicentre, randomised double-blind trial. As an adjunct therapy to levodopa in patients with more advanced Parkinson's disease, ropinirole was reported to be as effective as bromocriptine and significantly more effective than placebo. In general in the comparisons with placebo ropinirole allowed a > or =20% reduction in the concomitant dose of levodopa without compromising efficacy in a significant proportion of patients and, in some trials decreased the amount of awake time spent in the 'off' state ('off' state is defined as a gradual return to parkinsonism despite adequate medication). Ropinirole was well tolerated either as monotherapy or as an adjunct to levodopa treatment. Nausea, dizziness and somnolence were the most commonly reported adverse events and were reported at a higher incidence by patients receiving ropinirole than by those receiving placebo. In patients with early Parkinson's disease, ropinirole generally showed a similar overall tolerability profile to bromocriptine although, over a 3-year period nausea was more commonly reported with ropinirole recipients. In a 5-year study, the incidence of dyskinesia was significantly lower with ropinirole than with levodopa regardless of levodopa supplementation. Prior to the addition of supplementary levodopa 5% of ropinirole recipients had experienced dyskinesia compared with 36% of those receiving levodopa.

CONCLUSIONS

In patients with early Parkinson's disease, ropinirole monotherapy was more efficacious than bromocriptine with regard to improvement in activities of daily living, and need for supplemental levodopa. Ropinirole recipients had a higher requirement for levodopa supplementation than levodopa recipients in a 5-year study, but the incidence of dyskinesia was significantly lower with ropinirole than with levodopa (markedly so in the one third of ropinirole recipients who were able to remain on monotherapy with no levodopa supplementation). Thus available data suggest that ropinirole may provide a means of treating early Parkinson's disease while minimising the risk of dyskinesia and delaying the need for supplemental levodopa in some patients. In addition, ropinirole is also efficacious in the management of more advanced Parkinson's disease in patients who are experiencing motor complications after long term levodopa use.

Medical treatment of later-stage motor problems of Parkinson disease

Parkinson disease progression is associated with the development of levodopa short-duration responses and dyskinesias, as well as gait freezing. Levodopa dose adjustment and adjunctive treatment with dopamine agonists form the major therapeutic strategies. Catechol O-methyltransferase inhibitors are also appropriate considerations, whereas other drugs, including selegiline, amantadine, anticholinergic agents, and propranolol, have a more minor role.

Ropinirole and pramipexole, the new agonists

Ropinirole and pramipexole are non-ergoline dopamine agonists which are relatively specific for the D2 family of dopamine receptors. They have side-effect profiles linked to peripheral and central dopaminergic stimulation, amenable to tolerance through a slow titration or the addition of domperidone in sensitive patients. They do not have the uncommon but problematic ergot-related side effects of bromocriptine and pergolide. Ropinirole and pramipexole have both been shown to be efficacious when used as monotherapy in early Parkinson's disease (PD), and have been suggested as being less likely than levodopa to lead to the early development of motor fluctuations and dyskinesias in this clinical setting. They have also been shown to be useful as adjunctive therapy to levodopa in advanced PD and to have a levodopa-sparing effect in these patients. Dose equivalents amongst the available dopamine agonists is difficult to know with certainty but has been estimated as follows: 30 mg of bromocriptine, 15 mg of ropinirole, 4.5 mg of pramipexole, and 3.0 mg of pergolide.

Dopamine agonists: what is the place of the newer compounds in the treatment of Parkinson's disease?

Three new dopamine agonists (cabergoline, pramipexole, ropinirole) have been put on to the market within the past months to treat patients with Parkinson's disease. Like any marketed dopamine agonists, the new compounds bind to the D2-like receptors. Pramipexole and ropinirole appear to be quite close drugs. Both are selective non ergot D2 (and preferentially D3) agonists, with an elimination half-life of 5 to 10 hours. Conversely, cabergoline is an ergot derivative, less selective for the D2 receptors, with a much longer elimination half-life (60 hours or more). In moderately advanced levodopa treated patients with Parkinson's disease and motor fluctuations, cabergoline, pramipexole and ropinirole all do significantly better than placebo in reducing UPDRS motor examination scores, time spent off and daily dose of levodopa. None of the 3 newer agonists proved to do significantly better than bromocriptine in this indication, at the cost of very similar adverse effects. In de novo levodopa naive patients, pramipexole and ropinirole did significantly better than placebo in short-term (few months) follow-up trials, at the cost again of classical dopaminergic adverse effects. Ropinirole was marginally more effective than bromocriptine, while its use induced the same risk of psychosis than the "old" reference agonist. Early treatment with cabergoline, compared with levodopa, in a long-term (5 year) study reduced the relative risk of developping motor complication by more than 50%. A similar study is presently on-going to compare ropinirole and levodopa. Clinical trials to assess putative neuroprotective effects are also on going with ropinirole and pramipexole. Up to now, the available clinical controlled data suggest that the newer dopamine agonists have very similar clinical effects with only minor superiority, if any, versus bromocriptine.

Management of early Parkinson's disease

The two major questions in the treatment of early PD are (1) Does selegiline slow neuronal loss and delay the progression of clinical disability? and (2) Should dopamine agonists be used as initial symptomatic therapy in early disease rather than levodopa/PDI to reduce long-term disability and delay the onset of motor fluctuations and dyskinesia? Selegiline affords neuroprotection for dopamine neurons in cell culture systems and the results of several clinical trials are consistent with the hypothesis that it is neuroprotective in Parkinson's disease. Several clinical trials have found that initial symptomatic therapy with dopamine agonist to which levodopa/carbidopa is later added when needed leads to a lower incidence of long-term motor complications. These strategies are now being tested in prospective, randomized, blinded trials, many of which include PET or SPECT scans to assess the rate of dopamine neuron loss. These trials will provide more definitive answers to guide the early medial management of Parkinson's disease in the future.

Motor fluctuations in Parkinson's disease: pathophysiology and treatment

At the initial stages of Parkinson's disease (PD), levodopa (LD) is able to reduce most motor symptoms and to significantly improve the patient's quality of life. However, in the vast majority of patients with prolonged LD usage, some decline in efficacy occurs and motor complications eventually begin to appear. These complications consist not only of daily fluctuations in the voluntary motor performance often accompanied by involuntary movements, but also of fluctuations in cognitive, autonomic, and sensory functions. Several recent studies on LD complications in PD have led to a better understanding of their pathophysiology and of the possible therapeutic interventions, and a summary of these findings is presented in this review. Different observations now suggest that postsynaptic pharmacodynamic factors play a major role in determining fluctuations in PD. Two explanations are given: chronic intermittent dopaminergic therapy may lead to postsynaptic receptor downregulation in PD; or, receptor changes in the striatum may occur independently of treatment as a result of structural adaptation of the postsynaptic dopaminergic system to the progressive decline of the nigrostriatal pathway. The hypothesis of reversible postsynaptic changes as the main mechanism underlying a fluctuating response to LD lends itself to a possible pharmacological manipulation of the dopaminergic response to reverse, or even avoid, motor fluctuations (initial monotherapy with dopamine agonists and early combination LD/dopamine agonists). The role of peripheral pharmacokinetics factors is also critical and the use of controlled release LD formulations, of monoamine oxidase (MAO)-B and of catechol-O-methyltransferase (COMT) inhibitors may all, to a different degree, improve such phenomena. In the last decade, there has been a resurgence in surgical therapies in advanced PD, due to higher levels of accuracy and safety provided by the new surgical devices, and to a more precise localization of the target areas allowed by the neurophysiological mapping techniques. The surgical procedures currently used in advanced PD are stereotactic brain lesions (internal globus pallidus and subthalamic nucleus), chronic brain stimulation (of the same nuclei) and striatal grafting of dopamine-producing cells. All these procedures have already shown their efficacy in the management of severe fluctuations in PD, but their indications, and relative advantages and disadvantages, are still the subject of considerable debate and controversy.

Clinical pharmacology of dopamine agonists in Parkinson's disease

Oral levodopa is the most effective symptomatic treatment for Parkinson's disease. Dopamine agonists are useful adjuvants to levodopa in the pharmacotherapy of parkinsonian patients. Monotherapy with dopamine agonists in early Parkinson's disease has been advocated in order to delay the occurrence of complications associated with long term administration of levodopa. The use of dopamine agonists alone provides an adequate antiparkinsonian effect in only a minority of patients. In early stages of Parkinson's disease, dopamine agonists can produce a clinical response comparable with levodopa but, thereafter, their efficacy wanes. Early initiation of combination therapy with levodopa and dopamine agonists appears to reduce the severity and delay the appearance of the complications associated with long term administration of levodopa. Currently, dopamine agonists are most commonly used in combination with levodopa in patients in advanced stages of the disease who experience fluctuations of their motor symptoms. Despite their different pharmacodynamic and pharmacokinetic profiles, the ergot derivatives bromocriptine, lisuride and pergolide appear to be very similar in terms of their clinical efficacy. Continuous dopaminergic stimulation by parenteral infusion of water-soluble dopamine agonists such as apomorphine and lisuride can overcome motor fluctuations in advanced Parkinson's disease. Other dopamine agonists such as cabergoline, pramipexole and ropinirole are currently being studied. Further studies with these compounds will be required to determine their efficacy and adverse effects in comparison with the currently available orally active ergot agonists. It has been suggested that oxidative stress resulting from dopamine metabolism may be reduced by the administration of dopamine agonists. These drugs may therefore slow the rate of progression of Parkinson's disease. At present, however, there is no convincing clinical data to support a neuroprotective effect of dopamine agonists.

Characterization of enhanced behavioral responses to L-DOPA following repeated administration in the 6-hydroxydopamine-lesioned rat model of Parkinson's disease

Long-term treatment of Parkinson's disease with dopamine-replacing agents such as L-3,4-dihydroxyphenylalanine (L-DOPA) is compromised by many side-effects, most notably involuntary movements, L-DOPA-induced dyskinesia. Acute challenge with dopamine-replacing drugs elicits a rotational response in the 6-hydroxydopamine (6-OHDA)-lesioned rat model of Parkinson's disease. This rotation is contraversive to the lesion and is considered to represent an antiparkinsonian effect. More recently, it has become clear that the rotational response shows plasticity and that repeated L-DOPA or apomorphine therapy is accompanied by a marked enhancement in this response. In this study, we demonstrate that the enhanced behavioral response to repeated dopamine-replacement therapy seen in the 6-OHDA-lesioned rat has pharmacological characteristics similar to L-DOPA-induced dyskinesia seen in MPTP-lesioned primates and man. Thus, the magnitude and rate of development of the enhanced response to L-DOPA treatment is related to both the number of doses and the size of the dose of L-DOPA administered. In contrast, de novo administration of dopaminergic drugs that are associated with a lower incidence of dyskinesia, e.g., bromocriptine or lisuride, does not lead to an enhanced behavioral response following repeated treatment. However, following a single "priming" administration of apomorphine, the rotational response elicited by subsequent bromocriptine administrations is enhanced with repeated treatment. Once established, the enhanced behavioral response to repeated L-DOPA-administration (6.5 mg/kg, twice daily) can, like L-DOPA-induced dyskinesia in man and MPTP-treated monkeys, be selectively reduced by coadministration of L-DOPA with the alpha2-adrenergic receptor antagonist yohimbine (10 mg/kg, -95%), the 5-HT uptake inhibitor 5-MDOT (2 mg/kg, -90%), or the beta-adrenergic receptor antagonist propranalol (10 mg/kg, -35%). While these rats do not exhibit symptoms of dyskinesia per se, this rodent model does exhibit behaviors, the underlying mechanism of which is likely to be similar to that underlying L-DOPA-induced dyskinesia and may prove useful in studying the molecular and cellular mechanisms of L-DOPA-induced dyskinesia in Parkinson's disease.

Effect of food on the pharmacokinetics of ropinirole in parkinsonian patients

AIMS

Ropinirole is a specific non-ergoline dopamine D2-receptor agonist with antiparkinsonian properties. The pharmacokinetic parameters of ropinirole taken in the fasted condition were compared with those when it was co-administered with food.

METHODS

This was an open, randomized, two sessions cross over study in 12 patients with Parkinson's disease, comparing the steady-state pharmacokinetic profiles of ropinirole on two different study days: 'fasted' and 'fed'.

RESULTS

The mean Cmax was lower in the 'fed' regimen than in the 'fasted' one (-25%, P=0.002). The median tmax was observed 2.6 h later in the 'fed' regimen than in the 'fasted' regimen (P<0.05). There was a slight but significant decrease in AUC(0,8 h) in the 'fed' regimen (P=0.03).

CONCLUSIONS

Food decreases the rate of absorption of ropinirole, but has little effect on the extent of absorption.

Ropinirole in the treatment of early Parkinson's disease: a 6-month interim report of a 5-year levodopa-controlled study. 056 Study Group

The efficacies of ropinirole and levodopa were compared after 6 months of treatment in a planned interim analysis of a 5-year, double-blind, randomized, multicenter study of patients with early Parkinson's disease requiring dopaminergic therapy. The percentage of improvement in the Unified Parkinson's Disease Rating Scale total motor examination score was significantly higher for levodopa (44%) than for ropinirole (32%). The proportion of "responders" (Unified Parkinson's Disease Rating Scale improvement of at least 30%) did not differ between groups (levodopa, 58%; ropinirole, 48%). There was no difference between the groups for improvement on the Clinical Global Impression scale in patients with Hoehn and Yahr stages I, I.5, or II, but a significantly higher proportion of patients with Hoehn and Yahr stages II.5 or III showed Clinical Global Impression score improvement with levodopa. Emergent adverse events occurred in 84% of patients in both treatment groups, the principal symptom in each group being nausea. The incidence of serious adverse events was low (8% for ropinirole, 9% for levodopa). The results suggest that ropinirole and levodopa are equally effective in less severe Parkinson's disease; in more advanced Parkinson's disease, levodopa is superior.