Treatment of Parkinson's disease with agents other than levodopa and dopamine agonists: controversies and new approaches

Real-world pharmacological treatment patterns of patients with young-onset Parkinson's disease in Japan: a medical claims database analysis

INTRODUCTION

Young-onset Parkinson's disease is reported to comprise 5-10% of all Parkinson's disease cases; however, as physicians encounter a limited number of these patients, their treatment patterns are still unclear.

METHODS

We performed a descriptive study using the large Japanese medical claims database to describe the epidemiology and real-world pharmacological treatment patterns of newly diagnosed patients with young-onset Parkinson's disease. Patients aged 21-50 years in whom Parkinson's disease was newly diagnosed between January 1, 2005 and March 31, 2016 were included. We excluded individuals with Parkinson's-related diseases and those using antipsychotics to eliminate the possibility of drug-induced parkinsonism. The patients' demographics, comorbidities, prescribing patterns, and changes in levodopa equivalent daily dose were analyzed.

RESULTS

We identified 131 newly diagnosed young-onset Parkinson's disease patients (median age, 44.2 years). The most common comorbidities were depression (23.7%), hypertension (23.7%), and insomnia (22.9%). Of these patients, 122 were prescribed antiparkinson drugs. During the study period, the proportion of patients who were prescribed dopamine agonists, levodopa, and anticholinergics were 77.1%, 44.3%, and 27.5%, respectively. Dopamine agonists (49.2%) were most commonly prescribed initially, followed by anticholinergics (23.8%), levodopa (19.7%), and others (4.1%). The levodopa equivalent daily dose increased steadily with longer disease duration.

CONCLUSIONS

Dopamine agonists were most frequently prescribed during the study period and were the initial treatment of choice. We also observed a change in levodopa equivalent daily dose over the disease course. This study provides a descriptive overview of real-world prescribing patterns in young-onset Parkinson's disease patients.

Initial treatment of Parkinson's disease in 2016: The 2000 consensus conference revisited

In 2000, a French consensus conference proposed guidelines for the treatment of Parkinson's disease (PD). Since then, new drugs have been concocted, new studies have been published and clinicians have become aware of some drug-induced adverse effects that were little known in the past. This has led us to reconsider the recommendations published 16 years ago. Thus, the aim of the present review is to present the recent data related to the different medications and non-pharmacological approaches available for PD, with a special focus on early-stage PD. Levodopa (LD), dopamine agonists (DAs), catechol-O-methyltransferase inhibitors (COMT-Is), anticholinergics, monoamine oxidase inhibitors (MAOB-Is) and amantadine have been considered, and their efficacy and safety for both motor as well as non-motor aspects are reported here. This has led to our proposal for a revised therapeutic strategy for the initiation of treatment in newly diagnosed PD patients, based on the available literature and the relative benefits/side effects balance.

The monoamine reuptake blocker brasofensine reverses akinesia without dyskinesia in MPTP-treated and levodopa-primed common marmosets

The common marmoset develops motor deficits after MPTP treatment and exhibits dyskinesia after chronic levodopa (L-dopa) dosing and subsequent re-challenge with L-dopa and other dopaminergic agents. We report on the actions of the potent monoamine reuptake blocker brasofensine on motor disability, locomotor activity, and dyskinesia in the 1-methyl-4-1, 2,3,6-tetrahydropyridine (MPTP) -treated marmoset model of Parkinson's disease. Oral administration of brasofensine (0.25, 0.5, 1.0, or 2.5 mg/kg) to MPTP-treated marmosets produced a long-lasting, dose-dependent increase in locomotor activity and reduction in disability scores. In addition, coadministration of the lowest dose of brasofensine (0.25 mg/kg orally) with a threshold oral dose of L-dopa (2.5 mg/kg) caused a marked increase in locomotor activity, greater than that produced by either drug alone. In other MPTP-treated marmosets previously primed to exhibit dyskinesia by repeated L-dopa dosing, brasofensine effectively reversed akinesia with a naturalistic and prolonged motor response without the appearance of dyskinesia or stereotypy. This finding contrasts with the severe dyskinesia, stereotypy, and hyperkinesis produced by equivalent doses of L-dopa. The ability of brasofensine to produce a prolonged and naturalistic antiparkinsonian response without eliciting dyskinesia after previous L-dopa priming may relate to actions on D(1) receptor-linked pathways. These findings suggest that monoamine reuptake blockade may be of value in the treatment of Parkinson's disease, both early in the disease course and when L-dopa-induced dyskinesias complicate treatment.

Reduction of Parkinsonian signs in patients with Parkinson's disease by dopaminergic versus anticholinergic single-dose challenges

We investigated the effect of an anticholinergic (biperiden) and a dopamine agonist (apomorphine) on tremor, rigidity, and akinesia in patients with idiopathic Parkinson's disease. In a standardized, crossover study design 17 patients received single-dose challenges of 5 mg biperiden intravenously and a previously determined dose of apomorphine subcutaneously on 2 consecutive days. Resting (RT), postural (PT), and action tremor (AT) were assessed using spectral analysis of accelerometer data, and Unified Parkinson's Disease Rating Scale (UPDRS) scores for rigidity and akinesia were determined before and after administration of the study drug. Both single-dose challenges significantly reduced the amplitude of RT, PT, and AT, but only apomorphine significantly reduced UPDRS scores for rigidity and akinesia. In only one patient was tremor reduced by the dopamine agonist but not by the anticholinergic. We found that anticholinergic and dopaminergic agents are both effective in reducing tremor in IPD, and there was no evidence for a selective anticholinergic responsiveness of parkinsonian tremor. Akinesia and rigidity, on the other hand, were not improved by biperiden. We therefore conclude that dopaminergic substances are as effective as anticholinergics in patients with parkinsonian tremor and additionally improve other parkinsonian signs.

GABAergic modulation of striatal cholinergic interneurons: an in vivo microdialysis study

Striatal cholinergic interneurons have been shown to receive input from striatal gamma-aminobutyric acid (GABA)-containing cell elements. GABA is known to act on two different types of receptors, the GABAA and the GABAB receptor. Using in vivo microdialysis, we have studied the effect of intrastriatal application of the GABAA-selective compounds muscimol and bicuculline and the GABAB-selective compounds baclofen and 2-hydroxysaclofen, agonists and antagonists, respectively, at GABA receptors, on the output of striatal acetylcholine (ACh). Intrastriatal infusion of 1 and 10 mumol/L concentrations of the GABAA antagonist bicuculline resulted in a significant increase in striatal ACh output, whereas infusion of 1 and 10 mumol/L concentrations of the GABAA agonist muscimol significantly decreased the output of striatal ACh. Both compounds were ineffective in changing the output of striatal ACh at lower concentrations. Infusion of concentrations up to 100 mumol/L of the GABAB-selective antagonist 2-hydroxy-saclofen failed to affect striatal ACh output, whereas infusion of 10 and 100 mumol/L baclofen, but not 0.1 and 1 mumol/L baclofen, significantly decreased the output of striatal ACh. Thus, agonist-stimulation of GABAA and GABAB receptors decreases the output of striatal ACh in a dose-dependent fashion, whereas the GABAAergic system appears to inhibit tonically the output of striatal ACh via GABAA receptors, but not via GABAB receptors. We hypothesize that although GABAA mediated regulation of striatal ACh occurs via GABA receptors on the cholinergic neuron, the GABAB mediated effects may be explained by presynaptic inhibition of the glutamatergic input of the striatal cholinergic neuron.

Memory and learning in early Parkinson's disease: evidence for a "frontal lobe syndrome"

Fifteen untreated patients in the earliest stages of Parkinson's disease were compared to fifteen age- and intellectually matched control subjects on a number of memory tasks assessing short- and long-term recall of both meaningful and unrelated material, semantic relations in the organization of memory, priming, and source forgetting, and the ability to form new stimulus-response associations under conditions of maximal task interference. While patients demonstrated considerable evidence of preserved function, impaired performance on a subgroup of tasks was consistent with selective frontostriatal system involvement. These findings are discussed with reference to the underlying pathological processes in Parkinson's disease.

Parkinson's disease: a conceptualization of neuropsychological deficits within an information-processing framework

Parkinson's disease patients are frequently impaired in a variety of neuropsychological tasks involving memory, perceptual motor performance and cognitive flexibility. Although various theories have been forwarded to explain specific impairments, few attempts have been made to account for all the deficits within a single theoretical framework. Furthermore, the frequent occurrence of dementia, the adverse side effects of medication and the motor symptoms of the disease tend to interfere with neuropsychological performance. This has hindered the clear delineation of the neuropsychological profile of Parkinsonian patients. The present paper examines the evidence for intellectual deficits in non-demented Parkinson's disease patients. A number of problems inherent in cognitive research on Parkinson's disease are discussed. The contribution of dementia, motor symptom severity and medication in the expression of these intellectual impairments is examined. It is suggested that many of the neuropsychological deficits described in Parkinson's disease may result from a common underlying deficit in some aspect of information processing. Although it is not possible to pinpoint the precise mechanism(s) involved on the basis of the available evidence, several possibilities are suggested by cognitive and electrophysiological data.

Amantadine: evaluation of reinforcing properties and effect on cocaine self-injection in baboons

The ability of amantadine to maintain self-injection behavior and to alter self-administration of cocaine was examined in baboons using a standard intravenous cocaine self-injection procedure. Responding was maintained under a FR 80- or 160-response schedule of intravenous cocaine delivery (0.32 mg/kg per injection). Each drug injection was followed by a 3-h time-out allowing a maximum of 8 injections/day. Vehicle or amantadine doses were substituted for cocaine for a period of 15 or more days. Evaluation of a wide range of amantadine doses (0.32-32 mg/kg per injection) showed that this compound did not maintain self-administration behavior above vehicle control levels. In another experiment using the cocaine self-injection baseline, amantadine (10 or 32 mg/kg per day) was administered via a chronic intravenous infusion. Cocaine self-injection behavior was maintained and re-initiated during chronic amantadine exposure, suggesting that the reinforcing efficacy of cocaine was not modified by chronic amantadine administration.

Conditioned rotational behavior in rats with unilateral 6-hydroxydopamine lesions of the substantia nigra

Rats with unilateral 6-hydroxydopamine lesions of the substantia nigra were given drug treatments which induced rotational behavior either ipsilateral (2.0 mg/kg D-amphetamine) or contralateral (0.5 mg/kg apomorphine) in a classical conditioning paradigm. Four days after four drug-environment pairings the rats rotated ipsilateral in the amphetamine-associated environment and contralateral in the apomorphine-associated environment. 6-OHDA-lesioned rats which received only drug or environment exposure exhibited a slight tendency to rotate ipsilateral in each environment. This conditioning of drug-induced rotational behavior may offer a useful model for the study of brain mechanisms in classical conditioning.

Bornaprine vs placebo in Parkinson disease: double-blind controlled cross-over trial in 30 patients

The study covers 30 patients with idiopathic Parkinson disease, 13 men and 17 women, aged between 50 and 70, on stabilized L-Dopa and/or bromocriptine, which failed to ensure adequate control of the symptoms, especially tremor. To this regimen was added Bornaprine/placebo in randomized sequence. The patients were tested according to the Webster Rating Scale before, during and after each stage of the treatment. Statistical analysis of the results showed the superiority of Bornaprine over the placebo in reducing tremor (p less than 0.01) and, to a lesser degree, some other parkinsonian symptoms. No noteworthy side effects were found apart from dryness of the mouth, which was more frequent with Bornaprine.

The treatment of Parkinson's disease

In the management of Parkinson's disease physicians now have at their disposal a number of useful therapeutic tools (Figure 3). (Formula: see text) Anticholinergic drugs and amantadine suffice in the early stages of the disease when little disability is present. Levodopa combined with a peripheral decarboxylase inhibitor is the treatment of choice thereafter, and with the appearance of fluctuations it is necessary to increase the frequency of dosage of levodopa and to consider adding bromocriptine. Stereotactic surgery is useful in patients with severe tremor which is unresponsive to drug therapy.