Bromocriptine and its use in Parkinsonism

Computational study on new natural compound agonists of dopamine receptor

Dopamine receptor, a polypeptide chain composed of 7 hydrophobic transmembrane regions, is a new and vital drug target, especially Dopamine receptor 2(D2). Targeting dopamine receptors, Dopamine receptor agonists are a class of drugs similar in function and structure to dopamine and can directly act on dopamine receptors and activate it. Clinically, Dopamine receptor agonist drugs have achieved significant therapeutic effects on prolactinoma and Parkinson's Disease. In the study, we virtually screened a series of potential effective agonists of Dopamine receptor by computer techniques. Firstly, we used the Molecular Docking (LibDock) step to screen out some molecules that can dock well with the protein. Then, analysis of toxicity prediction and ADME (adsorption, distribution, metabolism and excretion) were carried out. More precise molecular docking (CDOCKER) and 3-Dimensional Quantitative Structure-Activity Relationship Modeling Study(3D-QSAR) pharmacophore generation were implemented to research and explore these compounds' binding mechanism with Dopamine receptor. Last but not least, to assess compound's binding stabilities, we carried out a molecular dynamic analysis. As the results show, two compounds (ZINC000008860530 and ZINC000004096987) from the small molecule database (ZINC database) were potential effective agonists of Dopamine receptor. These two compounds can combine with Dopamine receptor with higher affinity and proved to be no toxic. The cell experiment showed that two compounds could inhibit the proliferation and PRL secretion of MMQ cells (pituitary tumor cells). Thus, this study provided valuable information about Dopamine receptor agonist-based drug discovery. So, this study will benefit patients with prolactinoma and Parkinson's disease a lot.

Bromocriptine/levodopa combined versus levodopa alone for early Parkinson's disease

BACKGROUND

Drugs that mimic dopamine, such as bromocriptine (BR), were introduced as monotherapy or in combination with levodopa (LD) in the hope that this approach would prevent or delay the onset of motor complications in patients with Parkinson's disease (PD). However, hitherto, the role of BR has remained controversial. We present a systematic review of all randomised controlled trials (RCTs) of BR/LD combination therapy compared with LD monotherapy in PD.

OBJECTIVES

To assess the efficacy and safety of BR/LD combination therapy in delaying the onset of motor complications associated with LD monotherapy in patients with PD.

SEARCH STRATEGY

We searched the Movement Disorders Group trials register which includes MEDLINE and EMBASE; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); handsearched appropriate neurology journals, symposia reports, PD handbooks and reference lists of reviews found by the search-strategy. We also contacted Sandoz -now Novartis- (manufacturer of BR) and PPD Pharmaco and contacted colleagues who had co-ordinated trials on BR.

SELECTION CRITERIA

RCTs were eligible for inclusion if they evaluated the efficacy of BR/LD combination therapy for delaying the onset of motor complications compared with LD monotherapy in patients with PD. Outcome measures evaluated included the occurrence and severity of motor complications, impairment and disability scores, side effects and dropouts.

DATA COLLECTION AND ANALYSIS

To determine the feasibility of a quantitative systematic review two independent reviewers evaluated the methodological quality of identified trials and extracted data from the trials.

MAIN RESULTS

The methodological quality of seven trials showed important shortcomings. All studies failed adequately to describe randomisation procedures. Only three were carried out according to a double-blind design. Differences were found between studies concerning the mean age of the participants, the BR titration phase, the maximum achieved daily dose of LD (62.5 to 1000 mg) and BR (5 to 50 mg), and the applied outcomes. Our results show no evidence of consistent differences between treatment groups concerning the occurrence and severity of motor complications, scores of impairment and disability, or the occurrence of side effects.

AUTHORS' CONCLUSIONS

This systematic review revealed no evidence to support the use of early BR/LD combination therapy as a strategy to prevent or delay the onset of motor complications in the treatment of PD.

Bromocriptine/levodopa combined versus levodopa alone for early Parkinson's disease

BACKGROUND

Drugs that mimic dopamine such as bromocriptine were introduced as monotherapy or in a combination with LD in the hope that this approach would prevent or delay the onset of motor complications in patients with Parkinson's disease (PD). However, hitherto, the role of bromocriptine (BR) in this issue has remained controversial. The present study is a systematic review of all randomised controlled trials of bromocriptine/levodopa (BR/LD) combination therapy compared with levodopa (LD) monotherapy in PD.

OBJECTIVES

To assess the efficacy and safety of BR/LD combination therapy in delaying the onset of motor complications associated with LD monotherapy in patients with PD.

SEARCH STRATEGY

Sources including the Cochrane Library, the search strategy of the Movement Disorders Group (includes computerised searches of MEDLINE and EMBASE and hand searching of appropriate neurology journals), reference lists of the reviews found by the MEDLINE and EMBASE search-strategy, Sandoz -now Novartis- (manufacturer of BR), PPD Pharmaco, symposia reports, PD handbooks, contacts with colleagues who had co-ordinated trials on BR and reference lists of all included studies were used to identify randomised controlled trials (RCTs) of interest.

SELECTION CRITERIA

Randomised trials were eligible for inclusion if they evaluated the efficacy of BR/LD combination therapy for delaying the onset of motor complications compared to LD monotherapy in PD patients. Outcome measures that were evaluated included occurrence and severity of motor complications, scores on impairment and disability, and the occurrence of side effects and dropouts.

DATA COLLECTION AND ANALYSIS

To determine the feasibility of a quantitative systematic review two independent reviewers evaluated the methodological quality of identified trials.

MAIN RESULTS

The methodological quality of five trials showed important shortcomings. All studies failed to adequately describe randomisation procedures. Only two were carried out according to a double-blind design. Differences between studies concerning the mean age of the patients, the BR titration phase, the maximum achieved daily dose of LD (62.5-1000 mg) and BR (5-50 mg), and the applied outcomes were found. Our results show no evidence of consistent differences concerning the occurrence and severity of motor complications, scores of impairment and disability and the occurrence of side effects between both treatment groups.

REVIEWER'S CONCLUSIONS

This systematic review found no evidence in support of early bromocriptine/levodopa combination therapy as a strategy to prevent or delay the onset of motor complications in the treatment of PD.

Long-term observation of chronic subcutaneous administration of lisuride in the treatment of motor fluctuations in Parkinson's disease

Twenty-nine patients with advanced Parkinson's disease were treated with subcutaneous lisuride infusion in addition to a basic therapy consisting of levodopa + PDI in all, and deprenyl in some patients. At the time of the report, 13 patients are still receiving lisuride infusion after 5-36 months, while 16 have dropped out after 0.5-30 months: one because of psychosis, three because of insufficient efficacy, three due to death unrelated to treatment, three because of difficulties in handling the pump as outpatients, and six for other reasons. "Off"-periods and Parkinsonian disability in "off" and in "on" were reduced significantly. These improvements remained constant throughout the observation period. Once the optimal dose regimen is established, only minor adjustments of the doses of lisuride and levodopa are required in the individual case.

Result of chronic levodopa therapy and its modification by bromocriptine in Parkinson's disease

15 years' experience with Parkinson's disease treated with levodopa was compared to the 15 years before the advent of levodopa. Progression to severe disability and death was prolonged, at each stage of severity, by 3 to 5 years. At each duration of illness, the percentage of patients with severe disability was reduced significantly. There was some indication that independence was prolonged by early treatment. Life expectancy was increased to approximately that of the unaffected population. However, especially with patients with onset of disease before the age of 50, fluctuations of therapeutic response and severe abnormal involuntary movements interfered with satisfactory therapeutic results. Supplemental bromocriptine produced a smoother therapeutic response and decreased "off" period dystonia and leg pains in over 70% of patients. At dosages below 20 mg daily, it was not particularly effective in severely affected disabled patients. Adverse reactions prevented the use of bromocriptine in less than 20% of patients.

Bromocriptine in the management of end of dose deterioration in Parkinson's disease

Thirty-three patients with advanced Parkinson's disease complicated by end of dose deterioration were treated with bromocriptine. The drug was slowly increased so that by treatment week 24 the mean daily dose of bromocriptine was 22mg and levodopa had been decreased by an average of 15 percent. The majority of improvement in daily fluctuations and Parkinsonian disability score was documented by 8 weeks, at which time the mean daily bromocriptine dose was only 12mg. End of dose deterioration was reduced in 78 percent of the patients (mean 43% improvement). Total Parkinsonian disability score was decreased by 33 percent. Adverse effects were minimal; the most common was mild transient early treatment nausea which occurred in 15 percent of the patients. The slow introduction of small doses of bromocriptine, combined with minimal levodopa reduction, can give Parkinsonian patients significant improvement in end of dose deterioration.

Bromocriptine in Parkinson's disease: results obtained with high and low dose therapy

The results obtained with high and low dose bromocriptine therapy were compared in a review assessing the per cent of patients showing improvement (not taking account of the extent of improvement). It is concluded that the response rate with low dose bromocriptine is as good as that obtained with high dose therapy for both de novo and levodopa treated patients. The incidence of adverse effects is similar in the high and low dose treatment groups. More levodopa reduction results in a higher daily bromocriptine requirement. A statistical analysis of 61 bromocriptine-levodopa treated patients showed no positive correlation between bromocriptine dose and severity or duration of Parkinson's disease.