Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

These studies characterise the pharmacology of ropinirole, a selective D-2 agonist. High-affinity human caudate binding revealed a Ki for D2 receptors of 2.9 x 10(-8) M with no affinity for D1 at 10(-4) M in the rat. Ropinirole was weakly active at alpha 2-adrenoceptors and 5-HT2 receptors but inactive at 5-HT1, benzodiazepine and gamma-aminobutyric acid receptors or alpha 1 and beta-adrenoceptors. In rodents, ropinirole, like apomorphine, caused biphasic spontaneous locomotor activity and contralateral circling in 6-OHDA-lesioned mice with no tolerance to the latter after 14 days treatment. Amphetamine caused ipsilateral responses in the lesioned mice. Ropinirole did not cause marked stereotypies. In marmosets ropinirole (0.05-1.0 mg/kg SC or 0.1 mg/kg PO) reversed all motor and behavioural deficits induced by MPTP. This response started 10-20 minutes after dosing, and exceeded 2 hours. No tolerance was seen following chronic b.i.d. treatment. Similar results were obtained with 1-dopa plus benserazide; however, 1-dopa always caused emesis, whereas beneficial effects were shown with ropinirole in the absence of this side effect. These results support the continued clinical assessment of ropinirole for the treatment of Parkinson's disease.
 ...
PMID:Preclinical pharmacology of ropinirole (SK&F 101468-A) a novel dopamine D2 agonist. 167 48

Forty-six patients with Parkinson's disease experiencing motor fluctuations and not optimally controlled on levodopa received as adjunct therapy a new nonergoline dopamine agonist, ropinirole, in a 3-month randomized placebo-controlled trial. Ropinirole significantly reduced the duration of off periods as assessed by self-scoring diary cards. There were more nonserious dopaminergic adverse events in the ropinirole group. More patients withdrew because of adverse events or insufficient therapeutic effect in the placebo group. Ropinirole has beneficial adjuvant effects in parkinsonian patients with moderate motor disability and motor fluctuations.
 ...
PMID:Ropinirole in the treatment of levodopa-induced motor fluctuations in patients with Parkinson's disease. 872 42

Ropinirole is a novel, non-ergoline dopamine agonist chemical name with a very high specificity for dopamine D2-like receptors, currently being investigated for the symptomatic treatment of Parkinson's disease. The efficacy of ropinirole has been investigated in three placebo-controlled studies: one using ropinirole as monotherapy in early Parkinson's disease and two using it as an adjunct to L-dopa in patients who are experiencing fluctuations in motor response. Ropinirole therapy for 12 weeks was an effective symptomatic therapy in both patient groups, as measured by either a significant improvement in the motor score of the UPDRS, reduction of awake time spent "off" or a reduction in the dose of L-dopa. Ropinirole therapy was generally well tolerated, the most frequent adverse events being nausea and vomiting which are typical of all dopamine agonists, but unlike other dopamine agonists, CNS side-effects were of the same magnitude as found patients receiving placebo.
 ...
PMID:Ropinirole in the symptomatic treatment of Parkinson's disease. 874 30

The use of dopamine agonists as monotherapy or in combination with levodopa in the treatment of Parkinson's disease (PD) allows for reduction or limitation of the levodopa dose, potentially delaying the onset or reducing the severity of late motor complications. Ropinirole is a new nonergoline dopamine agonist that binds specifically to D2-like receptors with a selectivity similar to that of dopamine (D3 > D2 > D4). The chemical structure of ropinirole has the potential to maintain a structure-activity relationship similar to that of dopamine and other effective dopamine agonists without producing ergot-related adverse effects. Ropinirole has demonstrated efficacy in two standard preclinical models of PD and has shown a very low propensity to induce dyskinesia in these studies. This latter property is of potential clinical importance for pharmacotherapy of early PD. This article will present the importance of pharmacologic specificity of dopamine agonists along with the basic pharmacologic characteristics of ropinirole that may contribute to its efficacy in the treatment of PD.
 ...
PMID:Pharmacologic profile of ropinirole: a nonergoline dopamine agonist. 922 75

A prospective, randomized, placebo-controlled, double-blind, parallel-group, 6-month study assessed the efficacy and safety of ropinirole, a nonergoline D2-dopamine agonist, in patients with early Parkinson's disease (n = 241; Hoehn & Yahr stages I to III) with limited or no prior dopaminergic therapy. Patients (mean age, 62.8 years), stratified by concomitant use of selegiline, were randomized to ropinirole (n = 116) or placebo (n = 125). The starting dose of ropinirole was 0.25 mg tid with titration to at least 1.5 mg tid (maximum dose, 8 mg tid). Primary efficacy endpoint was the percentage improvement in Unified Parkinson's Disease Rating Scale (UPDRS) motor score. Ropinirole-treated patients had a significantly greater percentage improvement in UPDRS motor score than patients who received placebo (+24% vs -3%; p < 0.001). Ropinirole was well tolerated and patient withdrawals were infrequent. Most adverse experiences were related to peripheral dopaminergic activity. Ropinirole monotherapy is an effective and well-tolerated therapeutic option for treatment of early Parkinson's disease.
 ...
PMID:Ropinirole for the treatment of early Parkinson's disease. The Ropinirole Study Group. 927 May 67

In contrast to levodopa (L-dopa), de novo administration of the D2-like receptor agonist bromocriptine to patients with Parkinson's disease (PD) or to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated subhuman primates is not associated with the onset of significant dyskinesia. We now compare the ability of the novel D2-like selective dopamine agonist ropinirole with that of bromocriptine and L-dopa to induce dyskinesia in MPTP-treated common marmosets. MPTP-treated common marmosets were treated with placebo, L-dopa plus carbidopa, ropinirole, or bromocriptine daily for 30 days (n = 4 per group) in doses that were titrated to similarly increase locomotion and improve motor disability. L-dopa rapidly induced dyskinesia of moderate to severe intensity, whereas ropinirole and bromocriptine produced mild dyskinesia over the course of the study that was significantly less severe than in the L-dopa-treated group (p < 0.05). However, in a separate group of marmosets previously primed with L-dopa to exhibit dyskinesia, ropinirole administration elicited severe dyskinesias comparable with that of L-dopa in a dose-dependent fashion. Ropinirole, in common with bromocriptine, has a lesser tendency than L-dopa to produce dyskinesia while similarly improving motor performance in drug-naive MPTP-treated marmosets. However, in common with other dopamine agonists, ropinirole will elicit comparable dyskinesia once L-dopa priming has occurred. These results predict a similar response to ropinirole and other long-acting dopamine agonists in L-dopa-naive patients with PD and emphasize the importance of avoiding initial dyskinesia induction through early use of dopamine agonist drugs.
 ...
PMID:De novo administration of ropinirole and bromocriptine induces less dyskinesia than L-dopa in the MPTP-treated marmoset. 953 35

Ropinirole is a novel, nonergoline, selective D2-type dopamine agonist developed to treat Parkinson's disease. Safety data from therapeutic studies involving 1364 patients receiving ropinirole are reported (mean daily dose 8.7 mg, early therapy; 8.2 mg adjunct therapy). In early therapy, the emergent adverse experiences more common with the ropinirole group compared with placebo were nausea, somnolence, leg edema, abdominal pain, vomiting, dyspepsia, and hallucinations. In adjunct therapy, they were dyskinesia, nausea, hallucinations, and confusion. Most adverse experiences were mild and associated with a similar withdrawal rate compared with the placebo group. Except for hallucinations, the incidence of emergent adverse experiences decreased with time, despite increasing doses. Long-term adverse experiences particularly associated with ergoline-type dopamine agonists have so far not been observed with ropinirole. Only 1.2% of patients receiving ropinirole developed dyskinesia compared with 11.2% receiving L-dopa in early therapy over a mean period of 17 months. There were no clinically significant changes in cardiovascular parameters or laboratory data. The incidence of adverse experiences in the bromocriptine group was low, possibly because of a slow titration scheme and low average dose. Overall, the safety profile of ropinirole appears similar to that of other dopamine agonists. Clinical studies are continuing to assess the long-term safety and efficacy of ropinirole.
 ...
PMID:The safety of ropinirole, a selective nonergoline dopamine agonist, in patients with Parkinson's disease. 961 8

Ropinirole, 4-[2-(dipropylamino)ethyl]-1,3-dihydro-2H-indol-2-one, is a potent anti-Parkinson's disease drug developed by SmithKline Beecham Pharmaceuticals. Capillary zone electrophoresis (CZE) was used for the determination of the dissociation constants of ropinirole and five structurally related impurities, potentially formed during its synthesis and for separation and quantification of these substances. The dissociation constants obtained from the CZE measurements were confirmed by UV spectrophotometry for some of the test compounds, obtaining a good agreement between the values. Careful optimization of the running buffer composition permitted base-line resolution of the six compounds in a borate buffer containing acetonitrile and magnesium sulfate (a 100 mM borate buffer containing 30 mM MgSO4 and 20 vol.% of acetonitrile). It was shown that CZE can determine the level of these impurities, down to a level of 0.05% of the main component within 15 min.
 ...
PMID:Determination of the dissociation constants of ropinirole and some impurities and their quantification using capillary zone electrophoresis. 989 82

The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, dosage and administration, and formulary considerations of ropinirole are reviewed. Ropinirole is a nonergoline dopamine agonist that binds to dopamine D2-receptors; the drug is indicated for use in the symptomatic treatment of early and late Parkinson's disease (PD). Ropinirole is rapidly absorbed after oral administration and undergoes extensive hepatic metabolism to active metabolites. The elimination half-life averages about six hours. Ropinirole has a low potential to interact with other drugs likely to be administered to PD patients. In patients with early PD, initial monotherapy with ropinirole was more effective than placebo or bromocriptine in the absence of selegiline and was as effective as bromocriptine in the presence of selegiline. Ropinirole was as effective as levodopa in patients with earlier stages of PD. In one subset of patients with advanced PD not adequately controlled by levodopa, adjunctive ropinirole was more effective than placebo and bromocriptine. Ropinirole was more effective than bromocriptine in patients previously given high-dose levodopa and was as effective in patients previously given low-dose levodopa or adjunctive dopamine agonist therapy. The most frequent adverse effects are nausea, somnolence, and dizziness; the dosage should be increased gradually to minimize adverse effects. Ropinirole is less expensive than bromocriptine and pergolide and similar in cost to pramipexole. Ropinirole appears to be a useful addition to existing therapeutic approaches to PD and is approved for both early and later stages of the disease.
 ...
PMID:Ropinirole: a dopamine agonist for the treatment of Parkinson's disease. 1003 May 5

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.
 ...
PMID:Dopamine agonists: what is the place of the newer compounds in the treatment of Parkinson's disease? 1033 91


1 2 3 4 5 6 7 Next >>