Practice Parameter: Treatment of Parkinson disease with motor fluctuations and dyskinesia (an evidence-based review): [RETIRED]

Molecular and clinical prodrome of Parkinson disease: implications for treatment

The development of interventions to slow or prevent progression represents an important aim for current research into Parkinson disease (PD). General agreement prevails that success in this endeavor will depend on a clearer understanding of etiology and pathogenesis, and several important advances have recently been made, particularly in defining the genetic causes of PD. Studies of the biochemical consequences of the mutations that cause familial PD, and postmortem brain studies of idiopathic, sporadic PD, have highlighted mitochondrial dysfunction, oxidative stress, and protein metabolism by the ubiquitin-proteasomal and autophagy systems as being central to pathogenesis. In parallel with advances in etiopathogenesis, a clearer perception has developed of the clinical prodrome of PD, offering an opportunity to identify individuals who are at risk of PD, as well as those in the earliest clinical phase of the disease that might even precede the onset of motor symptoms. These populations are potentially the most suitable in which to test new protective therapies, and to study potential peripheral markers of disease progression. The awareness of the early symptomatic period of PD also raises the possibility of providing treatments that not only improve motor function but might also favorably modify outcome.

Long-term results of a multicenter study on subthalamic and pallidal stimulation in Parkinson's disease

We report the 5 to 6 year follow-up of a multicenter study of bilateral subthalamic nucleus (STN) and globus pallidus internus (GPi) deep brain stimulation (DBS) in advanced Parkinson's disease (PD) patients. Thirty-five STN patients and 16 GPi patients were assessed at 5 to 6 years after DBS surgery. Primary outcome measure was the stimulation effect on the motor Unified Parkinson's Disease Rating Scale (UPDRS) assessed with a prospective cross-over double-blind assessment without medications (stimulation was randomly switched on or off). Secondary outcomes were motor UPDRS changes with unblinded assessments in off- and on-medication states with and without stimulation, activities of daily living (ADL), anti-PD medications, and dyskinesias. In double-blind assessment, both STN and GPi DBS were significantly effective in improving the motor UPDRS scores (STN, P < 0.0001, 45.4%; GPi, P = 0.008, 20.0%) compared with off-stimulation, regardless of the sequence of stimulation. In open assessment, both STN- and GPi-DBS significantly improved the off-medication motor UPDRS when compared with before surgery (STN, P < 0.001, 50.5%; GPi, P = 0.002, 35.6%). Dyskinesias and ADL were significantly improved in both groups. Anti-PD medications were significantly reduced only in the STN group. Adverse events were more frequent in the STN group. These results confirm the long-term efficacy of STN and GPi DBS in advanced PD. Although the surgical targets were not randomized, there was a trend to a better outcome of motor signs in the STN-DBS patients and fewer adverse events in the GPi-DBS group.

Orally disintegrating selegiline in Parkinson patients with dopamine agonist-related adverse effects

OBJECTIVE

To determine whether adding orally disintegrating selegiline (ODS) while decreasing dopamine agonist (DA) dosages would reduce DA-related adverse effects (AEs) of excessive daytime sleepiness (EDS), pedal edema, hallucinations, and impulse control disorders (ICDs) without compromising efficacy in Parkinson disease (PD) patients.

METHODS

This was a 12-week open-label study of 60 PD patients with motor fluctuations and DA-related AEs of EDS, pedal edema, hallucinations, and ICDs. Orally disintegrating selegiline was initiated at 1.25 mg once daily, and down titration of the DA was started with a goal of a 50% reduction by 1 week. At week 6, ODS was increased to 2.5 mg, and further reductions of the DA were allowed if the AEs were not resolved.

RESULTS

The addition of ODS allowed a reduction in the mean daily dose of pramipexole from 2.3 to 0.5 mg and immediate-release ropinirole from 11.2 to 2.9 mg. Most subjects reported a reduction or resolution of DA-related AEs; 94% with EDS (n = 50), 73% with pedal edema (n = 26), 86% with hallucinations (n = 15), and 84% with ICDs (n = 25). Mean activities of daily living and motor scores from the Unified Parkinson's Disease Rating Scale as well as quality-of-life scores were significantly improved without an increase in daily "off" time. The most common AEs, most of which resolved after titration, were worsening of PD, nausea/vomiting, dyskinesia, increased off time, body aches, insomnia, orthostatic hypotension, and increased anxiety and depression.

CONCLUSIONS

In most subjects, the addition of ODS with decreasing dosages of DAs substantially reduced EDS, pedal edema, hallucinations, and ICDs without compromising efficacy.

The Impact of COMT-inhibition on Gastrointestinal Levodopa Absorption in Patients with Parkinson's Disease

The drug Levodopa (LD) is an efficient compound for the treatment of patients with Parkinson's disease (PD). Its short half life generates plasma behaviour of LD with peaks and troughs. Therefore, following the LD transport into the brain and the conversion to dopamine, an alternating stimulation of nigrostriatal postsynaptic dopamine receptors takes place. In the long term these fluctuations of dopamine concentrations supports onset of motor complications (MC) in PD patients. General opinion is that loss of central compensatory mechanisms of dopamine metabolism is responsible for the development of MC. However, in the periphery, LD troughs are preponderantly associated with the MC wearing off, which is the reappearance of motor symptoms with decreasing drug effect. Addition of the catechol-O-methyltransferase (COMT) inhibitor Entacapone (EN) to LD/carbidopa (CD) improved wearing off, since EN prolongs LD half life and avoids troughs. Plasma LD peaks are mostly related to the clinical manifestation of the MC dyskinesia, which appear as involuntary movements. One time addition of EN to a LD/CD formulation showed no increase of peripheral maximum LD concentration. But repeat combination of EN to each LD/CD intake elevated plasma LD bioavailability and peaks. Therefore switch from a LD/CD–-to a LD/CD/EN regime may also ask for reduction of LD/CD dosing or delay of the next LD/CD intake, to avoid onset of the most common peak dose dyskinesia. In conclusion, pharmacokinetic studies on peripheral LD metabolism and mode of intake underline their importance as peripheral components for MC manifestations in PD patients.

Dyskinesia and the antiparkinsonian response always temporally coincide: a retrospective study

OBJECTIVE

To clinically characterize the temporal relationship between dyskinesia and the antiparkinsonian response when dyskinesia first emerges during long-term levodopa therapy and to determine if it is consistent with the hypothesized mechanism by which dyskinesia develops.

METHODS

Dyskinesia and the antiparkinsonian response to levodopa during 2-hour levodopa infusions were monitored at intervals through the first 4 years of long-term levodopa therapy in 20 subjects with idiopathic Parkinson disease (PD) and previously untreated with levodopa. The onset and offset of the antiparkinsonian response and dyskinesia were compared when dyskinesia first appeared during the 4 years. The findings were compared to 20 subjects with PD on long-term levodopa with dyskinesia and motor fluctuations.

RESULTS

The onset and offset of the antiparkinsonian response and dyskinesia generally coincided when dyskinesia first appeared during the 4 years and did not suggest any temporal dissociation of the 2 responses. Further, the latency to the onsets of dyskinesia and the antiparkinsonian response tended to shorten during long-term levodopa therapy, suggesting that both responses were sensitized by long-term levodopa.

CONCLUSIONS

The similar onsets and offsets of the antiparkinsonian response and dyskinesia when dyskinesia first appears are not consistent with the postulated progressive decrease in threshold for dyskinesia during long-term levodopa therapy. Other mechanisms for the development of dyskinesia need to be considered.

Therapy for dyskinesias in Parkinson’s disease patients

Dyskinesia hampers the quality of life for most Parkinson’s disease patients following several years of therapy. However, the severity of L-Dopa-induced dyskinesia (LID) varies between patients, being quite tolerable in late-onset patients. Understanding the pathogenesis of LID has contributed to the development of a set of therapeutic strategies, including the choice, in early stages, of the least pulsatile regimen of dopamine-receptor activation. In cases where LIDs are already disabling, there is only a limited number of options: the optimization of ongoing DOPA-centered treatment, the utilization of glutamate antagonists and the exploration of the benefits of antipsychotic agents. More radical solutions are provided by deep brain stimulation in the subthalamic nucleus (or internal pallidus). This approach has proved efficacious in reducing LID, largely because it allows a reduction in dopaminergic daily doses. Stereotactic neurosurgery has fuelled several lines of investigation regarding the crosstalk between the basal ganglia and motor cortex. Here, we will present interesting evidence highlighting the potential for repetitive transcranial stimulation in reducing the occurrence of LID. The future may disclose important new avenues for the treatment of LIDs, given the current development of promising agents that might target different facets of dyskinesia, such as the impairment of striatal plasticity and non-Dopaminergic contributors such as adenosine, nitric oxide and the nucleotide cascade.

Pharmacotherapy in Parkinson's disease: case studies

Parkinson's disease is a common neurodegenerative disorder with the particular feature of having various available treatments with proven efficacy. However, no treatment is curative. Recent trial results provided data for the discussion about the potential disease-modifying effect of new drugs as well as of other therapeutic strategies. The changing clinical phenotype following the progression of the disease multiplies the number of treatment targets and makes the application of recommendations from guidelines or other treatment algorithms to the individual patient a complex task. In the present manuscript, we discuss the treatment management of three case studies illustrating different stages of disease with distinct phenomenology. The proposed therapeutic alternatives are discussed based on the best data available; that is, treatment guidelines, clinical trial results or observational data.

Current strategies in the treatment of Parkinson's disease and a personalized approach to management

Parkinson's disease is a progressive, neurodegenerative disorder affecting millions of people worldwide. Given the aging population, the prevalence of the disease is expected to increase substantially. The mainstay of treatment has been dopamine replacement therapy with carbidopa, levodopa, dopamine agonists, monoamine oxidase type B inhibitors, catechol-O-methyltransferase inhibitors and amantadine. Nonmotor features, such as cognitive impairment, mood disorders, autonomic dysfunction, gastrointestinal and genitourinary dysfunction, have a substantial impact on Parkinson's disease patients and their quality of life. This review will provide an overview on medications currently available for management of both motor and nonmotor symptoms of Parkinson's disease. Focus will be placed on recent and evolving studies evaluating symptomatic and neuroprotective effects of medications, and how such studies may impact the future management of Parkinson's disease.

Orodispersible sublingual piribedil to abort OFF episodes: a single dose placebo-controlled, randomized, double-blind, cross-over study

S90049, a novel sublingual formulation of the non-ergoline D(2)-D(3) agonist piribedil, has a pharmacokinetic profile promising to provide rapid relief on motor signs in Parkinson's disease (PD). We assessed the efficacy and safety of S90049 in aborting OFF episodes responding to subcutaneous apomorphine in PD patients with motor fluctuations. This was a single-dose double-blind double-placebo 3 x 3 cross-over study. Optimal tested doses were determined during a previous open-label titration phase (S90049 median dose: 60 mg, apomorphine: 5 mg). Primary endpoint was the maximal change versus baseline in UPDRS motor score (Delta UPDRS III) assessed after drug administration following an overnight withdrawal of antiparkinsonian medications. Thirty patients (age: 60 +/- 8 years, PD duration: 12 +/- 6 years, UPDRS III OFF: 37 +/- 15) participated. S90049 was superior to placebo on Delta UPDRS III (-13 +/- 12 versus -7 +/- 9 respectively; estimated difference -5.2, 95% Confidence Interval (CI)[-10.4;0.05], P = 0.05). This was also true for secondary outcomes: number of patients switching from OFF to ON (17 on S90049 vs. 8 on placebo, P = 0.03), time to turn ON (P = 0.013) and duration of the ON phase (P = 0.03). In the 17 patients who switched ON on S90049, Delta UPDRS III was similar on S90049 (-21.2 +/- 10.1) and apomorphine (-23.6 +/- 14.1) (estimated difference: 4.0 95% CI [-2.9;10.9]). S90049 was well tolerated: no serious or unexpected adverse event occurred. A single dose of up to 60 mg of S90049 given sublingually was superior to placebo in improving UPDRS III and aborting a practical OFF in patients with advanced PD. Testing greater doses might improve response rate.

Assessment of Parkinson disease manifestations

Parkinson disease (PD) is a progressive neurologic condition that causes motor and nonmotor manifestations. Treatment provides symptomatic benefit but no current treatment has been proven to slow disease progression. Research studies of PD require a means of rating the severity of disease by measurement of motor manifestations, assessment of ability to perform daily functional activities, and symptomatic response to medication. The most common rating scales are the Unified Parkinson Disease Rating Scale (UPDRS), Hoehn and Yahr staging, and the Schwab and England rating of activities of daily living. Each of these rating scales are described, including detailed instructions on how to implement these ratings. Although these are the most widely applied rating scales of PD, there are still substantial limitations to these scales that must be considered when using them for research. Finally, some common applications of these scales are described.

Deep brain stimulation in Parkinson's disease

During the last 15 years deep brain stimulation (DBS) has been established as a highly-effective therapy for advanced Parkinson's disease (PD). Patient selection, stereotactic implantation, postoperative stimulator programming and patient care requires a multi-disciplinary team including movement disorders specialists in neurology and functional neurosurgery. To treat medically refractory levodopa-induced motor complications or resistant tremor the preferred target for high-frequency DBS is the subthalamic nucleus (STN). STN-DBS results in significant reduction of dyskinesias and dopaminergic medication, improvement of all cardinal motor symptoms with sustained long-term benefits, and significant improvement of quality of life when compared with best medical treatment. These benefits have to be weighed against potential surgery-related adverse events, device-related complications, and stimulus-induced side effects. The mean disease duration before initiating DBS in PD is currently about 13 years. It is presently investigated whether the optimal timing for implantation may be at an earlier disease-stage to prevent psychosocial decline and to maintain quality of life for a longer period of time.

Selegiline shortage: Causes and costs of a generic drug shortage

BACKGROUND

In September 2007, shortages of generic selegiline occurred, forcing patients to either switch to more expensive alternatives or forego treatment. We sought to evaluate prescription trends of generic selegiline and to quantify the economic impact of any resulting drug substitution of more expensive alternatives.

METHODS

We analyzed proprietary data from IMS Health on monthly prescriptions in the United States for selegiline and potential substitutes from February 2002 through December 2007. Linear regression was used to predict the number of expected prescriptions after August 2007 had a shortage not occurred. The main outcome measures were the changes in prescriptions filled and the economic impact of drug substitution.

RESULTS

Prior to the shortage, total prescriptions filled for generic selegiline decreased 42%, and supply consolidated into one company, Apotex Inc., Toronto, Canada, whose market share increased from 41% to 83%. During the first 4 months of the shortage, Apotex Inc. filled 10,500 fewer prescriptions than projected and other selegiline manufacturers filled 7,400 more than projected for a net shortage of 3,100 prescriptions. The number of branded selegiline capsules filled during this period increased by 1,800 above projections, and 1,300 prescriptions for generic selegiline were not refilled or substituted. The societal cost of substituting generic selegiline with branded capsules was $75,000 over the first 4 months of the shortage.

CONCLUSIONS

Generic drug shortages carry economic and health implications. Given ongoing consolidation in the generics drug industry, these shortages may become more common and may require heightened regulatory scrutiny of the generic drug industry.

Zonisamide: in Parkinson's disease

Zonisamide, a widely available antiepileptic drug, has been approved in Japan as adjunctive therapy with levodopa for the treatment of previously treated patients with Parkinson's disease. It is an oral 1,2-benzisoxazole-3-methanesulfonamide and is associated with increased striatal dopamine levels in animal models. In two 12-week, randomized, double-blind, multicentre trials in adult patients with inadequately controlled Parkinson's disease and receiving levodopa, zonisamide 25 mg once daily (the recommended dosage) significantly improved motor function from baseline at final assessment, as assessed by the Unified Parkinson's Disease Rating Scale (UPDRS) Part III total score (primary endpoint), compared with placebo. Zonisamide 25 mg once daily as adjunctive therapy with levodopa was generally well tolerated by patients with Parkinson's disease. The overall incidence of adverse events was not significantly different between zonisamide 25 mg once daily and placebo groups in the phase IIb/III trial.

Greater improvement in quality of life following unilateral deep brain stimulation surgery in the globus pallidus as compared to the subthalamic nucleus

While deep brain stimulation (DBS) surgery is a well-accepted treatment for Parkinson disease (PD) that improves overall quality of life (QoL), its effects across different domains of QoL are unclear. The study reported here directly compared the effects of unilateral DBS in subthalamic nucleus (STN) or globus pallidus (GPi) on QoL in 42 non-demented patients with medication-refractory PD. Patients were enrolled in the COMPARE trial, a randomized clinical trial of cognitive and mood effects of STN versus GPi DBS conducted at the University of Florida Movement Disorders Center. Patients underwent motor, mood, verbal fluency and QoL (Parkinson disease questionnaire: PDQ-39) measures before and 6 months following surgery. Groups experienced motor and mood improvements that did not differ by target. Patients with STN DBS evidenced a slight decrement on letter fluency. On average, all patients endorsed better overall QoL after surgery. However, despite similar motor and mood improvements, GPi patients improved more than STN patients (38 vs. 14%, respectively; P = 0.03). Patients reported better QoL on subscales of mobility, activities of daily living (ADLs), emotional well-being, stigma, cognition and discomfort, but not on those of social support and communication. Improvements on the mobility, ADLs, stigma and social support subscales were greater amongst GPi patients. In regression analyses, only depression changes independently predicted changes in overall QoL as well as emotional well-being and social support changes. Within the STN group only, declining category fluency scores correlated with poorer QoL on the communication subscale. Unilateral DBS in both STN and GPi improved QoL overall and in disparate domains 6 months after surgery. Patients receiving GPi DBS reported greater improvements that cannot be explained by differential mood or motor effects; however, verbal fluency changes may have partially contributed to lesser QoL improvements amongst STN patients.

Cognition and mood in Parkinson's disease in subthalamic nucleus versus globus pallidus interna deep brain stimulation: the COMPARE trial

OBJECTIVE

Our aim was to compare in a prospective blinded study the cognitive and mood effects of subthalamic nucleus (STN) vs. globus pallidus interna (GPi) deep brain stimulation (DBS) in Parkinson disease.

METHODS

Fifty-two subjects were randomized to unilateral STN or GPi DBS. The co-primary outcome measures were the Visual Analog Mood Scale, and verbal fluency (semantic and letter) at 7 months post-DBS in the optimal setting compared to pre-DBS. At 7 months post-DBS, subjects were tested in four randomized/counterbalanced conditions (optimal, ventral, dorsal, and off DBS).

RESULTS

Forty-five subjects (23 GPi, 22 STN) completed the protocol. The study revealed no difference between STN and GPi DBS in the change of co-primary mood and cognitive outcomes pre- to post-DBS in the optimal setting (Hotelling's T(2) test: p = 0.16 and 0.08 respectively). Subjects in both targets were less "happy", less "energetic" and more "confused" when stimulated ventrally. Comparison of the other 3 DBS conditions to pre-DBS showed a larger deterioration of letter verbal fluency in STN, especially when off DBS. There was no difference in UPDRS motor improvement between targets.

INTERPRETATION

There were no significant differences in the co-primary outcome measures (mood and cognition) between STN and GPi in the optimal DBS state. Adverse mood effects occurred ventrally in both targets. A worsening of letter verbal fluency was seen in STN. The persistence of deterioration in verbal fluency in the off STN DBS state was suggestive of a surgical rather than a stimulation-induced effect. Similar motor improvement were observed with both STN and GPi DBS.

Role of rasagiline in treating Parkinson's disease: Effect on disease progression

Rasagiline is a second generation, selective, irreversible monoamine oxidase type B (MAO-B) inhibitor. It has demonstrated efficacy in monotherapy for early Parkinson’s disease (PD) patients in one large randomized, placebo-controlled trial (TVP-1012 in Early Monotherapy for Parkinson’s Disease Outpatients), and has shown ability to reduce off time in more advanced PD patients with motor fluctuations in two large placebo-controlled trials (Parkinson’s Rasagiline: Efficacy and Safety in the Treatment of “Off”, and Lasting Effect in Adjunct Therapy With Rasagiline Given Once Daily). Preclinical data abound to suggest potential for neuroprotection by this compound against a variety of neurotoxic insults in cell cultures and in animals. The lack of amphetamine metabolites provides an advantage over the first generation MAO-B inhibitor selegiline. One large trial has investigated the potential for disease modification in PD patients (Attenuation of Disease progression with Azilect Given Once-daily) and preliminary results maintain some possible advantage to earlier initiation of the 1 mg/day dose. The clinical significance of the difference detected remains a consideration.

Attitudes and barriers to clinical practice guidelines in general and to the guideline on Parkinson's disease. A National Survey of German neurologists in private practice

Although much progress has been made in the development of clinical practice guidelines (CPGs), there are few strategies for dissemination and implementation of these guidelines. This study examines the attitudes of neurologists to CPGs and barriers to CPG implementation, with a particular focus on the Parkinson's disease CPG (PD-CPG). A cross-sectional survey was performed in 2007 with a representative sample of 213 neurologists in private practice in Germany. The main outcome measures were the Tunis Attitudinal Scale and barrier assessment of CPGs. In addition, the awareness, applicability, and usefulness of the PD-CPG were assessed. Most of the neurologists agreed that CPGs are intended to improve the quality of care (82.2%; n = 171), are good educational tools (59.4%; n = 120), and are an unbiased synthesis of expert opinion (58.9%; n = 119). The main barriers to guideline implementation were lack of time (39.3%; n = 81), inability to reconcile patient preferences with guideline recommendations (34.3%; n = 71), and lack of awareness (32.5%; n = 67). A total of 187 (88.2%) of the neurologists were aware of the PD-CPG, of whom 163 (92.6%) found it "beneficial" and 173 (94.6%) applied it in daily practice. Nevertheless, only 51 (28.8%) of neurologists considered that the guidelines led to an improvement in the quality of care. However, 63 (32%) favored a special guideline for patients. Qualitative data analysis revealed more positive than negative aspects of the PD-CPG; positive comments included "treatment facilitation", "a stepped therapy schema" and "increasing self-efficacy". Criticism mostly concerned the lack of relevance to everyday practice and the rigidity of the guidelines. Neurologists in private practice have a generally positive attitude to guidelines. The PD-CPG is well-known and often used, but its impact on quality of care is considered to be only modest. Thus, further research is needed to address issues of daily practice in future versions of the PD-CPG and to investigate the effects of implementation at the physician and patient levels.

Tolcapone: review of its pharmacology and use as adjunctive therapy in patients with Parkinson's disease

Levodopa has been the gold standard therapy for the motor symptoms of Parkinson’s disease for more than three decades. Although it remains the most effective treatment, its long-term use is associated with motor fluctuations and dyskinesias that can be disabling for patients and difficult for physicians to manage medically. In the last 10 years, the catechol-O-methyltransferase (COMT) inhibitor tolcapone has been studied for its efficacy as an adjunctive treatment to levodopa plus a dopa decarboxylase inhibitor. Adjunctive therapy with tolcapone can significantly reduce the dose of levodopa required. Moreover, treatment with tolcapone significantly reduces wearing off and on-off periods in fluctuating patients and improves ‘on’ time in patients with stable disease. Tolcapone has assumed a new place in the arsenal of medications for Parkinson’s disease. This paper reviews the pharmacology, safety and efficacy of tolcapone in patients with advanced Parkinson’s disease. After some initial concerns about its safety, tolcapone has been shown to be safe if used and monitored according to guidelines regarding liver function. Tolcapone produces expected dopaminergic side effects, including headache, nausea, insomnia, as well as diarrhea; however, these side effects are generally mild and as a rule do not result in discontinuation of therapy.

A review of ropinirole prolonged release in Parkinson's disease

Ropinirole prolonged release is a once-daily, 24-hour formulation of ropinirole, a non-ergot dopamine agonist. It is approved as monotherapy and as an adjunct to levodopa in the treatment of Parkinson's disease (PD). Several potential advantages of ropinirole prolonged release compared to the immediate release formulation include maintaining more consistent dopaminergic activity with steadier plasma levels, increased tolerability, greater compliance from a simpler once-daily dosing regimen and ease in dose titration. In a randomized, double-blind, non-inferiority, crossover study, ropinirole prolonged release was shown to have comparable efficacy and tolerability to immediate release ropinirole in early PD patients, with significantly greater compliance. Subjects were converted overnight between ropinirole formulations without loss of efficacy and with good tolerability. In a randomized, double-blind, placebo-controlled study in advanced PD, daily "off" time was reduced by an average of 2.1 hours with ropinirole prolonged release compared to 0.4 hours with placebo. Patients on ropinirole prolonged release were also more likely to require less daily levodopa. Ropinirole prolonged release is well tolerated with a similar adverse effect profile to other non-ergot dopamine agonists. The most common adverse effects include dyskinesia, nausea, dizziness, hallucinations, somnolence, abdominal pain or discomfort and orthostatic hypotension. Ropinirole prolonged release is a safe and effective treatment option for both early and advanced PD. This manuscript briefly reviews the current pharmacological treatment options for PD and provides a more detailed review of the currently available data regarding ropinirole prolonged release as a treatment option for PD.

Ropinirole prolonged release: in advanced Parkinson's disease

Ropinirole prolonged release is a non-ergoline dopamine receptor agonist that is indicated for the treatment of Parkinson's disease. * Once-daily ropinirole prolonged release and three-times-daily ropinirole immediate release have similar exposure over 24 hours. The prolonged-release formulation is associated with fewer fluctuations in plasma ropinirole concentrations. * Two well designed, placebo- or active comparator-controlled trials examined the efficacy of ropinirole prolonged release in patients with advanced Parkinson's disease suboptimally controlled by levodopa. In the placebo-controlled trial, 24 weeks' therapy with ropinirole prolonged release 6-24 mg once daily reduced hours of 'off' time (primary endpoint) to a significantly greater extent than placebo. In the active comparator-controlled trial, significantly more ropinirole prolonged-release recipients than ropinirole immediate-release recipients maintained a >or=20% reduction from baseline in 'off' time at week 24 (primary endpoint). *Ropinirole prolonged release 6-24 mg once daily was generally well tolerated in patients with advanced Parkinson's disease; adverse events were generally typical of non-ergoline dopamine receptor agonists.

Adding a dopamine agonist to preexisting levodopa therapy vs. levodopa therapy alone in advanced Parkinson's disease: a meta analysis

BACKGROUND

To perform a meta analysis of randomised placebo-controlled trials evaluating the use of dopamine agonist (DA) or placebo to preexisting levodopa therapy for the treatment of advanced Parkinson's disease (PD). We focused on clinically important efficacy [Unified Parkinson's Disease Rating Scale (UPDRS) activities of daily living (ADL) and motor scores as well as change in 'off' time and levodopa dose] and safety outcomes (withdrawal because of adverse drug events (ADEs), dyskinesias, hallucinations and mortality).

METHODS

A systematic literature search was performed between January 1990 and July 2007. The primary outcome measures assessed were the reduction in scores of Unified Parkinson's Disease Rating Scale (UPDRS) activities of daily living (ADL) and motor scores as well as reduction in 'off' time and reductions in levodopa dose from baseline. Safety end-points were also evaluated.

RESULTS

A total of 15 trials (n = 4380 subjects) were included in the meta analysis. Adjunctive DA use resulted in greater improvement as measured by the UPDRS ADL [weighted mean difference (WMD) -2.20, 95% confidence interval (CI) -2.64 to -1.76; p < 0.0001] and motor score reduction (WMD -5.56, 95% CI -6.82 to -4.31; p < 0.0001) as well as reduction in 'off' time measured in hours/day (WMD -1.20, 95% CI -1.78 to -0.62; p < 0.0001) and reduction in levodopa dose (WMD -128.5 mg, 95% CI -175.0 to -82.1; p < 0.0001) vs. placebo. Incidence of dyskinesia and hallucinations was higher with DAs [odds ratio (OR) 3.27, 95% CI 2.65-4.03; p < 0.0001] and (OR 3.34, 95% CI 2.44-4.58; p < 0.0001). Non-ergot DAs were qualitatively better, although both ergot and non-ergot DAs showed statistically significant improvements in all UPDRS scores.

CONCLUSION

Adjunctive DA use to levodopa is superior to levodopa alone in reducing PD symptoms in patients not controlled with monotherapy. DAs seem especially useful amongst PD patients with wearing-off phenomenon from levodopa therapy, but can cause some adverse events.

Levodopa-related wearing-off in Parkinson's disease: identification and management

BACKGROUND

Levodopa is currently the most effective treatment for Parkinson's disease (PD); however, long-term levodopa therapy often results in motor complications, such as motor fluctuations and dyskinesia. The initial complication is commonly wearing-off, which is the re-emergence of motor and non-motor symptoms before the next scheduled levodopa dose.

OBJECTIVE

The purpose of this article was to review published literature that discusses wearing-off, focusing on the role of the healthcare professional, including the primary care physician, in the effective management of wearing-off.

METHODS

An electronic literature search was conducted using MEDLINE and EMBASE to find articles discussing wearing-off and its management using the following keywords: 'Parkinson's disease'; 'wearing-off'; 'levodopa'; 'primary care'.

FINDINGS AND CONCLUSIONS

Current evidence indicates that a consistent delivery of levodopa should improve long-term symptomatic efficacy and may prevent or delay motor complications. A number of therapeutic options are available to optimize therapeutic outcome, including modification of the levodopa dose or dosing schedule,switching to another levodopa formulation and the use of adjunct therapies, such as catechol-O-methyl transferase inhibitors, dopamine agonists and monoamine oxidase-B inhibitors. The management of wearing-off is dependent upon the early identification of symptoms and the initiation of effective treatment. Key issues are the need to educate patients and to facilitate good communication with both primary and secondary healthcare professionals. In most cases, patients with PD initially present to primary healthcare professionals who may refer the patient to a neurologist once disease management becomes more complex. However, in many cases, especially in rural areas where neurologists may not be widely available, the primary healthcare professionals may manage the patient throughout the disease course. Limitations of this review include the restricted search criteria and selected search period.

L-dopa therapy for Parkinson's disease: past, present, and future

Dopamine (DA) supplementation therapy by l-dopa for Parkinson's disease (PD) was established around 1970. The dose of l-dopa can be reduced by the combined administration of inhibitors of peripheral l-amino acid decarboxylase (AADC), catechol O-methyltransferase (COMT), or monoamine oxidase B (MAO B). DA in the striatum may be produced from exogenously administered l-dopa by various AADC-containing cells, such as serotonin neurons. The long-term administration of l-dopa in PD patients may produce l-dopa-induced dyskinesia (LID), which may be due to chronic overstimulation of supersensitive DA D1 receptors. l-dopa may be used in combination with various new strategies such as gene therapy or transplantation in the future.

How do you treat motor complications in Parkinson's disease: Medicine, surgery, or both?

The motor complications associated with levodopa therapy, namely, fluctuations in motor response and dyskinesias, occur in the majority of Parkinson's disease patients. These complications can impair a patient's quality of life and even cause pronounced disability. "Off" states that result in freezing of gait and falling are disabling for many patients. Dyskinesias most commonly occur at peak dose and typically alternate with the wearing-off state. Once these problems appear, they usually persist, and the physician needs to make continual adjustments in medications to minimize these problems. Medical treatments should be attempted before treatments such as deep brain stimulation are considered because of the potential adverse effects that are associated with surgery. The timing of surgery, however, is also important because younger patients and less advanced patients tend to have a better outcome. There is thus a need for experienced and knowledgeable physicians and surgeons who are able to handle these motor complications. This review discusses available medications and surgical approaches, and their outcomes.

Pharmacologic treatment of advanced Parkinson's disease: a meta-analysis of COMT inhibitors and MAO-B inhibitors

OBJECTIVE

To perform a meta-analysis of randomized placebo-controlled trials evaluating catechol-O-methyltransferase (COMT) inhibitors or monoamine oxidase type B (MAO-B) inhibitors in addition to levodopa versus levodopa alone for the treatment of advanced Parkinson's disease (PD).

METHODS

A systematic literature search was performed between 1990 and October 2007. The primary outcome measures assessed were the reduction in scores of Unified Parkinson's Disease Rating Scale (UPDRS) total, activities of daily living (ADL) and motor scores from baseline. Other efficacy and safety endpoints were also evaluated.

RESULTS

A total of 13 trials (n=3775 subjects) were included in the meta-analysis. As compared to placebo, COMT and MAO-B inhibitor use resulted in greater improvement in UPDRS total score (weighted mean difference [WMD] -2.13, 95%CI -0.46 to -0.20; and WMD -5.03, 95%CI -7.38 to -2.68) ADL scores (WMD -0.99, 95%CI -1.56 to -0.43; and WMD -1.48, 95%CI -2.13 to -0.83) and motor scores (WMD -1.50, 95%CI -2.70 to -0.30; and WMD -3.19, 95%CI -4.57 to -1.80) as well as increase in "on" time, reduction in "off" time and decreased need in levodopa dose compared to placebo. Incidences of dyskinesia were significantly higher with the COMT and MAO-B inhibitors compared to placebo.

CONCLUSION

The use of COMT or MAO-B inhibitors plus levodopa is superior to levodopa alone at reducing PD symptoms in patients with advanced PD. While combination therapies with COMT or MAO-B inhibitor plus levodopa seem especially useful amongst PD patients with wearing-off phenomenon, they are associated with more adverse events.

Risk of valvular heart disease associated with the use of dopamine agonists in Parkinson's disease: a systematic review

A literature review was conducted to assess risk of cardiac valve regurgitation (CVR) associated with use of ergot-derived and non-ergot dopamine agonists (DAs) in patients with Parkinson's disease (PD).

INCLUSION CRITERIA

case-control/observational studies of >10 patients with PD treated with DAs, including a control group and assessment of incidence/risk of CVR. Of the 166 publications identified, 14 met all inclusion criteria and included 1,750 patients. In 11 of the studies, a significant increase in CVR frequency of any severity (at the aortic, mitral or tricuspid valve) in the ergot group vs. the non-ergot or control group was described. No study reported increased risk of CVR for non-ergot DAs, compared with controls. In the studies identified in the literature, the use of ergot-derived DAs (pergolide and cabergoline) in patients with PD was associated with increased risk of CVR. Increased risk of CVR was not associated with the use of non-ergot DAs.

A decision tool to support appropriate referral for deep brain stimulation in Parkinson's disease

BACKGROUND AND OBJECTIVE

Although Deep Brain Stimulation (DBS) has been proven to be an effective treatment for patients with advanced Parkinson's disease (PD), it may be difficult for general neurologists to identify appropriate candidates for this procedure. We developed an electronic decision tool that can assist neurologists in deciding which PD patients should be referred for DBS consideration.

METHODS

Using the RAND/UCLA Appropriateness Method, an international expert panel assessed the appropriateness of referral for 972 theoretical patient profiles. Panel results were embedded in an electronic decision support tool which displays the panel statement on referral (appropriate, inappropriate and uncertain) after completion of the patient profile.

RESULTS

Referral was considered appropriate for 33% of the theoretical profiles. Logistic regression showed excellent internal consistency of the ratings (predictive value 92%). Symptom severity (OFF-symptoms, dyskinesias, refractory tremor) and PD duration were positively associated with the panel judgment that referral is appropriate. Presence of levodopa-resistant axial symptoms, age >or= 70 years and presence of cognitive impairment showed the strongest negative impact.

CONCLUSIONS

The RAND/UCLA method proved to be useful in determining the appropriate criteria for DBS referral. Validity and applicability of the decision tool (accessible via http://test.stimulus-dbs.org) in clinical practice need to be further determined.

Levodopa-induced dyskinesias and their management

This paper reviews the epidemiology, pathophysiology, clinical features and rationale for managing dyskinesias associated with Parkinson's disease. These are a common clinical problem occurring in up to 90% of patients and more frequently affect those with early-onset. Dyskinesias have a negative impact on quality of life and are an important cause of disability. Their precise etiology is still poorly understood, although it is recognized that dopaminergic pre-synaptic and post-synaptic mechanisms are involved together with extra-dopaminergic factors. The phenomenology of dyskinesias encompasses a variable mixture of two prevalent features: dystonia and chorea. We have studied their time course following a single acute levodopa challenge and have found that dystonia occurs throughout the duration of the on period, whereas choreiform movements occur only at the peak of therapeutic dopaminergic motor responses. This allows a schematic relationship to be drawn between a short duration motor response and the occurrence of dystonia and chorea. There is currently no satisfactory treatment for dyskinesias. Managing the therapeutic window does not provide an adequate solution due to the appearance of a dyskinesia threshold dose that narrows the therapeutic margin. High frequency stimulation of the subthalamic nucleus probably has some specific anti-dyskinetic action, but is limited by the small number of patients who are candidates for this treatment. Research efforts are currently focused on the development of specific anti-dyskinetic medications. Their availability will certainly change the current clinical practice and will widen again the therapeutic window of dopaminergic medications that has now become too narrow.

Medical management of motor fluctuations

Given the magnitude of the problem of motor fluctuations in patients who have Parkinson's disease treated with levodopa, a significant effort has been expended by physicians, researchers, and pharmaceutical manufacturers over the years to find effective treatments. This article briefly reviews the medical options for managing motor fluctuations that are in common use in the United States or that are expected to be available soon.

Tolcapone in elderly patients with Parkinson's disease: a prospective open-label multicenter non-interventional trial

Safety and efficacy of tolcapone was studied in 237 patients with advanced Parkinson's disease (PD) in a prospective, open-label, multicenter, non-interventional trial. Main outcome measures were tolerability (adverse events=AE) and safety parameters (liver enzymes). A subgroup analysis was performed for patients at < 70 years and > or = 70 years of age. Improvement of symptoms based on investigator global assessment was reported in 84% of all patients: 14.8% greatly improved, 42.6% improved, and 27% slightly improved. Slight worsening was reported in only 2.6% of subjects. There were no significant differences concerning the treatment efficacy between the age subgroups (p=0.74). The incidence of AE was slightly higher in the subgroup of patients > or = 70 years than in the subgroup of patients < 70 years (relative risk, RR=3.03; 95% confidence interval, CI=1.04-8.96; p=0.03), but AE judged as potentially related to tolcapone were equally distributed among both groups (8.5% vs. 2.9%, RR: 2.91; CI=0.82-10.27; p=0.08). Diarrhea was the most common potentially tolcapone-related AE in both groups. Elevations of liver enzymes (aspartate aminotransferase=AST, and alanine aminotransferase=ALT) above the upper limit of normal were observed in 19% (CI=8.3-23.4) of all patients with slightly but not statistically significant higher percentages in the young patients group compared to older patient group (RR=0.54; CI=0.28-1.04; p=0.06). This observational study provides evidence that tolcapone can be effectively and safely used for the treatment of response fluctuations in elderly patients with PD.

Cognitive declines one year after unilateral deep brain stimulation surgery in Parkinson's disease: a controlled study using reliable change

Conflicting research suggests that deep brain stimulation surgery, an effective treatment for medication-refractory Parkinson's disease (PD), may lead to selective cognitive declines. We compared cognitive performance of 22 PD patients who underwent unilateral DBS to the GPi or STN to that of 19 PD controls at baseline and 12 months. We hypothesized that compared to PD controls, DBS patients would decline on tasks involving dorsolateral prefrontal cortex circuitry (letter fluency, semantic fluency, and Digit Span Backward) but not on other tasks (Vocabulary, Boston Naming Test), and that a greater proportion of DBS patients would fall below Reliable Change Indexes (RCIs). Compared to controls, DBS patients declined only on the fluency tasks. Analyses classified 50% of DBS patients as decliners, compared to 11% of controls. Decliners experienced less motor improvement than non-decliners. The present study adds to the literature through its hypothesis-driven method of task selection, inclusion of a disease control group, longer-term follow-up and use of Reliable Change. Our findings provide evidence that unilateral DBS surgery is associated with verbal fluency declines and indicate that while these changes may not be systematically related to age, cognitive or depression status at baseline, semantic fluency declines may be more common after left-sided surgery. Finally, use of Reliable Change highlights the impact of individual variability and indicates that fluency declines likely reflect significant changes in a subset of patients who demonstrate a poorer surgical outcome overall.

Viral parkinsonism

Parkinson's disease is a debilitating neurological disorder that affects 1-2% of the adult population over 55 years of age. For the vast majority of cases, the etiology of this disorder is unknown, although it is generally accepted that there is a genetic susceptibility to any number of environmental agents. One such agent may be viruses. It has been shown that numerous viruses can enter the nervous system, i.e. they are neurotropic, and induce a number of encephalopathies. One of the secondary consequences of these encephalopathies can be parkinsonism, that is both transient as well as permanent. One of the most highlighted and controversial cases of viral parkinsonism is that which followed the 1918 influenza outbreak and the subsequent induction of von Economo's encephalopathy. In this review, we discuss the neurological sequelae of infection by influenza virus as well as that of other viruses known to induce parkinsonism including Coxsackie, Japanese encephalitis B, St. Louis, West Nile and HIV viruses.