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

We reviewed the histories of patients seen in a large Parkinson's disease clinic from 1983 to 1989 to determine if there is a relationship between the timing of initiation of levodopa therapy and the development of motor response fluctuations, dyskinesias, and dementia. There were no factors predisposing to the development of response fluctuations or dementia. Younger age at disease onset predisposed to the development of dyskinesia. Dyskinesias occurred in a greater proportion of patients in whom the initiation of levodopa therapy was delayed by more than 2 years from disease diagnosis than among those in whom treatment was started earlier. We thus failed to identify any adverse consequences of early levodopa treatment in our patient population.
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PMID:"Early" initiation of levodopa treatment does not promote the development of motor response fluctuations, dyskinesias, or dementia in Parkinson's disease. 202 75

Inconsistencies in the response to individual levodopa doses occur in most patients with advanced Parkinson's disease (PD). To investigate the possible development of acute tachyphylaxis, we evaluated the effects of repeated injections of intravenous levodopa in 10 PD patients with motor fluctuations by administering, during a single day, a previously determined optimal levodopa dose repeatedly each time motor function returned to baseline. Peak antiparkinsonian response was lower by 20%, and peak plasma levodopa levels lower by 35% following the first dose compared with all subsequent doses. Neither peak dyskinesia scores nor the duration of motor response changed significantly with successive levodopa doses. These data suggest that pulsatile levodopa administration does not acutely alter dopamine receptor responsiveness, and that other pharmacokinetic and pharmacodynamic factors contribute to the dose-to-dose variability in response to levodopa.
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PMID:Acute effects of pulsatile levodopa administration on central dopamine pharmacodynamics. 202 76

Alterations in the density of dopamine receptor subtypes and behaviors mediated by the D1-selective agonist SKF-38393 were examined in rats treated chronically with reserpine, SKF-38393 or the combination of these drugs. Animals received either vehicle or reserpine (1 mg/kg s.c.) on days 1 to 28 and, in addition, half of each of these groups were treated with vehicle and half were treated with SKF-38393 (5-10 mg/kg s.c.) on days 15 to 29. Quantitative autoradiographic measurement of D1 receptors labeled with [3H]SCH-23390 and D2 receptors labeled with [3H]spiroperidol revealed that chronic administration of reserpine increased the density of both receptor subtypes in the nucleus accumbens and caudate-putamen, but not in the substantia nigra. Chronic administration of SKF-38393 alone did not alter D1 receptor density in any of these regions. However, chronic administration of the agonist in reserpinized animals decreased D1 receptor density in the nucleus accumbens, but not in the caudate-putamen or substantia nigra, demonstrating that this partial agonist can selectively down-regulate D1 receptors when endogenous dopaminergic tone is removed. The chronic drug treatments also altered behavioral responses. Chronic administration of SKF-38393 alone produced sensitization of the oral dyskinesia response elicited by a challenge injection of the agonist, but no significant change in the grooming response. Acute administration of SKF-38393 in rats treated with reserpine for 14 days produced stereotypy which was not altered after chronic administration of the agonist. Surprisingly, chronic administration of reserpine alone produced a spontaneous oral dyskinesia, which was blocked dose-dependently by the D2-selective antagonist spiroperidol. These findings are discussed in terms of their relevance to Parkinson's disease and tardive dyskinesia.
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PMID:Behavioral and neurochemical effects of chronic administration of reserpine and SKF-38393 in rats. 203 24

Urinary retention or incontinence is not an infrequent clinical finding in patients with neuroleptic malignant syndrome. We studied the pathophysiology of this voiding disorder by urodynamic testing. It revealed involuntary bladder contraction and rigidity of external sphincter (dyskinesia). These findings are analogous to those in Parkinson disease patients and support the dopamine deficiency theory as the cause of neuroleptic malignant syndrome.
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PMID:Neurogenic bladder in neuroleptic malignant syndrome. 203 88

Six patients with Parkinson's disease (PD) and therapeutic response fluctuations (RF) on levodopa treatment participated in an open-label trial of L-deprenyl (Eldepryl) in conjunction with Sinemet. Deprenyl (10 mg/day) allowed a slight but not statistically significant 22% reduction of total daily levodopa intake after 4 weeks of treatment, with a significant but unsustained reduction in the number of daily "off" periods and an increase in the portion of waking day spent "on." Pharmacokinetic studies revealed no effect of deprenyl on the plasma levodopa concentration vs. time curve, or the coefficient of variation (C.V.) of plasma levodopa levels measured over an 8-h period. Plasma DOPAC levels were unaffected, suggesting that the majority of peripheral DOPAC is generated by action of MAO-A. For most patients, benefit was not maintained. Two patients have continued taking the drug, and both have enjoyed significant reductions in total levodopa dose. Both have mild end-of-dose failure and little dyskinesia. Since no changes in peripheral pharmacokinetics of levodopa could be demonstrated, any therapeutic action of deprenyl in PD would appear to be due to prolongation of dopaminergic activity within the CNS.
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PMID:L-deprenyl, levodopa pharmacokinetics, and response fluctuations in Parkinson's disease. 210 91

In five levodopa (L-dopa)-treated patients with Parkinson's disease with severe fluctuations of motor performance, plasma L-dopa as well as dopamine levels were measured during 2 days, first under optimal standard L-dopa with peripheral decarboxylase inhibitor (PDI) and then after a dose adjustment period using slow-release L-dopa/benserazide (Madopar HBS) in an open inpatient trial. Three patients benefited from the slow-release preparation; two patients deteriorated with a tendency to have an unpredictable response, a delay to turn "on" with the first dose in the morning, as well as an increase in dyskinesia corresponding to L-dopa cumulation during the day. These problems were subsequently also seen during the follow-up period of 1 year in those patients who benefited from Madopar HBS as inpatients. This might indicate that patient compliance is more difficult with the new formulation. After 1 year all patients had returned to their previous standard L-dopa/PDI treatment. L-Dopa levels continued to fluctuate, but to a lesser degree with Madopar HBS. The equivalent L-dopa dosage had to be increased by 56% (29-100%) with Madopar HBS while mean dopamine levels increased in four patients (by 47-257%) without the occurrence of peripheral side-effects. This implies that with the new formulation more L-dopa is metabolized to dopamine and explains the necessity to increase the equivalent L-dopa dosage.
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PMID:Controlled-release levodopa/benserazide (Madopar HBS): clinical observations and levodopa and dopamine plasma concentrations in fluctuating parkinsonian patients. 218 Oct 74

Madopar Hydrodynamically Balanced System (HBS), a new sustained-release levodopa preparation, was used to control severe nightly disabilities in 15 outpatients suffering from Parkinson's disease in an advanced state and with long-term levodopa therapy. This medication was given ante noctem in addition to an otherwise unchanged daily regimen of levodopa administration. In 13 patients a considerable diminution in nocturnal akinesia and in the frequency of waking up was reached with a mean dosage of 308 mg of Madopar HBS. Early morning akinesia was only slightly alleviated in four patients. The nocturnal off-period pain disappeared in one patient. Adverse effects consisted of nocturnal dyskinesia in two patients and early morning dystonia in another two patients. The regular use of sleeping pills was clearly reduced after Madopar HBS therapy.
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PMID:Madopar HBS in nocturnal symptoms of Parkinson's disease. 223 93

Fifty four patients with idiopathic Parkinson's disease receiving levodopa therapy were studied. Thirty three of these patients displayed peak-dose dyskinesia. Neither the duration of Parkinson's disease nor the duration of levodopa therapy discriminated between patients with and patients without peak-dose dyskinesia. Consequently, these criteria could not determine whether the first appearance of peak-dose dyskinesia depends on the duration of Parkinson's disease--a factor that is related to the severity of the disease--or on the duration of levodopa therapy. A subgroup of nineteen patients with unilateral or unequivocally asymmetrical peak-dose dyskinesia was examined 12 hours after withdrawal of levodopa. A levodopa testdose provoked unilateral or unilateral preponderant peak-dose dyskinesia which always involved the most severely affected side and which also happened to be the side of onset of the disease. This demonstrates that the severity of Parkinson's disease is the main risk factor for peak-dose dyskinesia.
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PMID:Severity of Parkinson's disease is a risk factor for peak-dose dyskinesia. 232 54

A retrospective study of variations of therapeutic response (dyskinesia and on-off phenomenon) in Parkinson's disease was conducted on 278 patients treated with levodopa for at least 6 months and hospitalized at National Neurological Institute "C. Besta" of Milan between 1974 and 1984. Variations of therapeutic response (TRV) were present in 105 of 278 patients; in this group, age at illness onset was significantly lower, while duration of levodopa treatment and also duration of illness were longer than in the group of patients without TRV. Multiple logistic regression analysis showed that the most important variables were age at illness onset and duration of treatment, but they were only modestly predictive. Other factors connected with progression of disease must also contribute to the TRV.
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PMID:Variation of therapeutic response in Parkinson's disease: a retrospective study. 237 40

Intermittent treatment with L-dopa over a 2-year period induced abnormal involuntary movements in MPTP-treated squirrel monkeys. Dyskinesias included a choreic and dystonic component. Dose-response curves for chorea and dystonia revealed that the same dose of L-dopa (30 mg/kg) induced the highest score for both dyskinesias: however, the severity was much greater for chorea. Choreic movements were always most prevalent at the time of peak effect, whereas dystonia was apparent at the time of peak effect and at "end-of-dose", and was occasionally observed spontaneously. Our findings indicate that squirrel monkeys treated with MPTP develop L-dopa-induced dyskinesias which closely resemble those observed in Parkinson's disease. This species provides a valuable animal model to develop improved therapeutic agents.
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PMID:Characterisation of dyskinesias induced by L-dopa in MPTP-treated squirrel monkeys. 239 4


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