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PubMed1978

Comparison between lergotrile and bromocriptine in parkinsonism.

The therapeutic and adverse effects of two ergot derivatives, bromocriptine and lergotrile, were compared in idiopathic parkinsonism. At both low (50 mg daily) and high (150 mg daily) dosage there was a similar but not identical profile of response. Initially, lergotrile tended to induce more severe but always transient hypotension. At higher doses, bromocriptine caused more dyskinesia. Neurological deficits improved with increasing doses up to an average daily level of 80 to 150 mg of ergot derivatives combined with levodopa, 450 to 1,150 mg, and carbidopa, 45 to 115 mg. However, efficacy often declined at the highest doses of antiparkinsonian agents. Adverse effects caused by ergot derivatives are more common with dosages greater than 100 mg per day. In general, the best overall therapeutic results with bromocriptine and lergotrile were obtained in the dose range of 50 to 100 mg daily for each. It is concluded that bromocriptine and lergotrile are similar in their therapeutic properties and that both are comparable in efficacy to levodopa plus carbidopa (though optimal results are commonly obtained by combining submaximal doses of levodopa with ergot derivatives). The role for each drug in the treatment of parkinsonism is likely to be determined by factors such as cost (bromocriptine) and hepatotoxicity (lergotrile).

Acetonitriles↗
PubMedDate not supplied

Pharmacokinetics and pharmacodynamics of bromocriptine in the rat.

The absorption, distribution, and excretion of bromocriptine were studied following oral and parenteral administration of non-radioactive and 14C-labelled drug in the rat. Total radioactivity was measured in blood, tissues, and excreta by liquid scintillation counting while the parent drug was determined in plasma and selected tissues by radioimmunoassay. The pharmacokinetic observations were compared with the time course of drug-induced hypothermia in cold-room acclimatized rats. The results indicated that oral doses of bromocriptine were rapidly, though incompletely (32-40 per cent), absorbed, but underwent extensive first-pass metabolism, resulting in an absolute bioavailability of only 6 per cent. The bioavailability increased to approximately 22 per cent in rats pretreated with the hepatic microsome inhibitor proadifen, thus suggesting the liver as the principal site of biotransformation. Absorbed bromocriptine showed preferential distribution into the tissues, although no apparent accumulation of drug-related material occurred in the body. The drug was eliminated almost exclusively by metabolism and biliary excretion into the faeces. Comparison of the pharmacodynamic and the pharmacokinetic profiles indicated a dose relationship between hypothermia and plasma bromocriptine concentrations but not total radioactivity levels. The hypothermic response was also intensified by proadifen pretreatment, thus confirming the parent drug as the pharmacologically active entity. It is believed that the previously reported delay in the onset of bromocriptine activity is not pharmacokinetic in nature, but is related to the properties of the receptors at the target site or to the pharmacologic events that result in the observed effects.

Animals↗
PubMedDate not supplied

Influence of estradiol on accessory reproductive organs in the castrated male rat. Effects of bromocriptine and flutamide.

Estradiol partially maintained the weights of the dorsolateral prostate and seminal vesicles in castrated adult male rats. One group of animals received subcutaneous injections of estradiol (0.01 mg/kg) daily, while a second group of animals received estradiol plus bromocriptine (4.0 mg/kg). Changes in weights of accessory reproductive organs were correlated with serum prolactin levels. Estradiol significantly increased serum prolactin levels while concomitant treatment with bromocriptine caused serum prolactin to remain at castrate levels. Bromocriptine slightly decreased, but did not abolish, the effect of estradiol on weights of the dorsolateral prostate and seminal vesicles. To determine if the effect of estradiol was mediated by androgen receptors in the dorsolateral prostate and seminal vesicles, a third group of animals was treated with flutamide. Flutamide, at a dosage (20 mg/kg) that abolished the effects of dihydrotestosterone on the weights of these tissues, produced no alternation of the effects of estradiol. Treatment of animals with a combination of flutamide, bromocriptine, and estradiol did not significantly alter organ weights from the results obtained with bromocriptine and estradiol. Scatchard plot analysis of the effect of estradiol treatment on cytosol binding of estradiol demonstrated increased quantities of estradiol binding in dorsolateral prostate and seminal vesicles which correlated with the changes in weights noted. Although part of the effect of estradiol on regression of male accessory reproductive organs of castrated rats may be mediated by prolactin, the principal effect appears to be a direct action on responsive tissues.

Anilides↗
PubMed2006

The Parkinson-Control study: a 1-year randomized, double-blind trial comparing piribedil (150 mg/day) with bromocriptine (25 mg/day) in early combination with levodopa in Parkinson's disease.

Dopamine agonists have been recommended as early treatment for Parkinson's disease (PD), alone or combined with levodopa. Piribedil is a non-ergot selective D(2)/D(3) agonist with alpha(2) antagonist properties shown to be effective in the treatment of PD. This 12-month international, randomized, double-blind trial aimed to assess the efficacy of piribedil 150 mg versus bromocriptine 25 mg, in early combination with levodopa in Stage I to III PD patients. Motor efficacy was assessed using the Unified Parkinson's Disease Rating Scale (UPDRS III, Items 18-31) as improvement from baseline. Response rate was defined as a 30% improvement. Among the 425 randomly assigned patients, 178 were also included in a substudy on cognitive follow-up evaluated by a dysexecutive syndrome oriented battery. A relevant improvement in UPDRS III over the 12-month study duration was observed both in the piribedil and bromocriptine groups (-7.9 +/- 9.7 points from baseline versus -8.0 +/- 9.5; not significant [n.s.]) with a response rate of 58.4% and 55.3% (n.s.), respectively. Piribedil and bromocriptine resulted in similar improvement on all UPDRS III subscores. Piribedil patients required less levodopa dose increase than those on bromocriptine. Cognitive performance remained generally unchanged in both groups, with a significant effect of piribedil limited to the Wisconsin Card Sorting Test. An overall good tolerability of piribedil was observed. Early combination of piribedil 150 mg with levodopa resulted in significant long-term improvement of all motor symptoms in PD patients insufficiently controlled by levodopa alone. Taking into account both efficacy and acceptability in the long-term, piribedil proved in this bromocriptine controlled study to be an effective and safe treatment for PD.

Adult↗
PubMed1986

The effect of single and repeated administration of bromocriptine on monoamine metabolism in rat brain and [3H]spiroperidol binding to striatal membranes.

Administration of a single high dose of bromocriptine decreased synthesis and release of dopamine and serotonin in several brain regions, most notably in the striatum. Bromocriptine modified the kinetics of [3H]spiroperidol binding to striatal membranes, but these changes were not prominent 2 h after injection when modifications of monoamine metabolism were evaluated. After injection of the same dose of bromocriptine daily for 10 days, the decrease in dopamine synthesis persisted, while other aspects of monoamine metabolism, presumably controlled by dopamine autoreceptors, returned to normal values. This adaptation was not caused by decreased blood levels of bromocriptine, since bromocriptine accumulated in plasma after repeated drug administration. This study provides evidence that different aspects of dopamine cell function, presumably controlled by autoreceptors, show different patterns of adaptation after chronic administration of dopamine agonists.

Animals↗
PubMed1998

De novo administration of ropinirole and bromocriptine induces less dyskinesia than L-dopa in the MPTP-treated marmoset.

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.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1994

Attenuation of the locomotor-sensitizing effects of the D2 dopamine agonist bromocriptine by either the D1 antagonist SCH 23390 or the D2 antagonist raclopride.

Injections of the selective D2 dopamine agonist bromocriptine (5.0 mg/kg, IP) produced progressively stronger locomotion over 10 days of repeated testing. Concurrent treatment with either the D1 antagonist SCH 23390 (0.01 or 0.1 mg/kg, IP) or the D2 antagonist raclopride (0.1 or 1.0 mg/kg, IP) suppressed bromocriptine-induced locomotion on treatment days and attenuated or blocked the progressive increases in locomotion that accompanied repeated injections of bromocriptine alone. The fact that D1 and D2 antagonists each block the acute actions of bromocriptine and attenuate the development of bromocriptine sensitization is suggested to imply a striatal rather than a ventral tegmental mechanism for the sensitization produced by repeated treatments with direct dopamine agonists.

Animals↗
PubMed2001

Bromocriptine administration lowers serum prolactin and disrupts parental responsiveness in common marmosets (Callithrix j. jacchus).

The influence of prolactin on parental responsiveness was investigated in eight unpaired, parentally inexperienced common marmosets (Callithrix jacchus; 6 female, 2 male). The marmosets were prescreened with infants (1-10 days of age) and required to exhibit short latency retrieval and infant carrying in at least three consecutive pretests as criterion for inclusion in this study. The marmosets were then administered the dopamine agonist bromocriptine (0.5 mg/0.5ml vehicle subcutaneously) and the vehicle alone (0.5 ml 10% ethanol solution) twice daily for 3 consecutive days in random order. Bromocriptine treatment reduced circulating prolactin to nondetectable levels. Bromocriptine treatment eliminated infant retrieval in four of the eight marmosets and was associated with significantly increased retrieval latencies and significantly reduced carrying durations in the four monkeys that continued to retrieve following bromocriptine treatment. When given the vehicle alone, the marmosets retrieved infants significantly faster than during pretests, suggesting a handling effect of the injection series. Bromocriptine treatments were associated with significantly increased movement during the tests. The results of this study indicate that prolactin and/or its regulatory neurotransmitters are involved in the control of the spontaneous display of parental responsiveness in common marmosets.

Aging↗
PubMed1986

Pharmacokinetics of a long-acting bromocriptine preparation (Parlodel LA) and its effect on release of prolactin and growth hormone.

The pharmacokinetics and endocrine actions of a long-acting form of bromocriptine (Parlodel) were examined in a controlled study in 10 healthy volunteers receiving a single i.m. injection of 50 mg. Six further subjects took bromocriptine 1.25 mg t.i.d. for 3 days p.o. In the subjects given the slow release preparation, the plasma bromocriptine concentrations increased sharply to a maximum of 1.65 mg/l 2 h after injection. This fast release process was followed by slow clearance with a half-life of 16 days. The substance was still detectable in plasma 35 days postinjection. Plasma prolactin (PRL) fell rapidly from a mean of 5.6 ng/ml to reach significantly lower levels at 60 and 120 min. Inhibition was maintained for up to 35 days, when plasma PRL was still significantly below the values recorded at baseline and in the control group. Plasma GH peaked at 3.6 ng/ml at 120 min and subsequently declined slowly to stabilize between 1.4 and 2.2 ng/ml for about 12 h, falling to below the 1 ng/ml limit for the remainder of the study period. In contrast, individuals receiving oral bromocriptine exhibited a significant elevation following the first dose and an equivalent increment after the morning dose on Day 3. Thus, the results show a prolonged inhibitory effect on PRL of this long-acting bromocriptine preparation in parallel with its slow plasma clearance. The stimulant effect on GH secretion is short lived, presumably due to desensitisation of specific receptors.

Adult↗
PubMed1992

The effects of dopamine, haloperidol and bromocriptine on intraocular pressure.

In a double-blind randomised, prospective single dose study, we measured intraocular pressure (IOP), pupil diameter, systemic blood pressure and heart rate in 43 ocular normotensive subjects before (baseline) and 2, 4, and 6 hours after topical instillation of the following drugs: dopamine 2% (n = 11), a dopamine receptor blocking drug, haloperidol 0.5% (n = 11), a dopamine receptor stimulating drug, bromocriptine 0.05% (n = 11) and 0.1% (n = 10). In the groups receiving dopamine or haloperidol, there were no significant differences in IOP compared with baseline values (p > 0.01). But, a significant decrease in IOP compared with the baseline values was found in both bromocriptine groups (p < 0.001). With the 0.05% and 0.1% concentrations, maximum reductions in intraocular pressure were 22.0% +/- 5.8% and 28.4% +/- 9.8%, respectively. No significant differences in mean pupil diameter, systemic blood pressure and heart rate were detected in all of these groups. In addition, in the group receiving bromocriptine 0.1%, there was no change in serum prolactin levels. These results suggest that topically administered bromocriptine has satisfactory intraocular pressure lowering capacity without serious ocular or systemic side effects. Consequently we conclude that, an ophthalmic formulation of bromocriptine may have substantial clinical potential for the treatment of glaucoma.

Adult↗
PubMed1995

Changes in the ultrastructural distribution of prolactin and growth hormone mRNAs in pituitary cells of female rats after estrogen and bromocriptine treatment, studied using in situ hybridization with biotinylated oligonucleotide probes.

The expression and distribution of prolactin (PRL) mRNA and their alterations induced by estrogen and bromocriptine were investigated using non-radioisotopic in situ hybridization (ISH) at the electron microscopic (EM) level. Our EM-ISH studies using biotinylated oligonucleotide probes showed that estrogen induced whirling changes of the rough endoplasmic reticulum (RER) of female rat PRL cells and increased transcription of PRL genes located on the polysomes of the whirling RER. The presence of mammosomatotroph cells in the rat pituitary gland was also verified in our EM-ISH studies. After bromocriptine administration, PRL cells contained many secretory granules due to the inhibition of secretion. Pre- and post-embedding EM-ISH and northern hybridization studies revealed that bromocriptine induced the distorted, vesiculated, and dilated RER, and also the suppressed PRL mRNA expression. The activity of protein kinase C (PKC), which mediates PRL gene expression, tended to be elevated by estrogen and suppressed by bromocriptine. Therefore, it is considered that the ultrastructural and quantitative changes in PRL mRNA expression evoked by estrogen and bromocriptine may be mediated by the intracellular signal transduction system, including PKC.

Animals↗
PubMed1981

The endocrine profile of bromocriptine: its application in endocrine diseases.

Bromocriptine, a potent agonist at Dz receptors, was developed as a therapeutic agent for inhibiting prolactin (PRL) secretion in patients with hyperprolactinemia. Besides, its PRL-suppressive effect and a short-lasting growth hormone (GH)-releasing effect in normal volunteers, bromocriptine has no other endocrine effects in healthy subjects. On the other hand, bromocriptine lowers GH secretion in acromegalic patients and ACTH secretion in some patients with Cushing's disease or Nelson's syndrome. The paper reviews the endocrine actions of bromocriptine in man, in normal and pathological conditions, the bromocriptine's mechanism of action and its clinical applications in endocrinology.

Bromocriptine↗
PubMed1993

Lack of cross-sensitization between the locomotor-activating effects of bromocriptine and those of cocaine or heroin.

Rats were given daily injections of bromocriptine (5.0 mg/kg IP) or vehicle either in the home cage or in a test box equipped with photocells to measure locomotion. The animals were then tested in the photocell boxes for their locomotor response to cocaine (10.0 mg/kg IP), heroin (0.5 mg/kg IP), or quinpirole (0.1 mg/kg IP). Repeated bromocriptine in the test box but not in the home cage caused progressive increases in sensitivity to the locomotor-stimulating effects of bromocriptine and increases in the subsequent sensitivity to quinpirole but caused only trivial signs of cross-sensitization to cocaine or heroin. Cross-sensitization to quinpirole was temporary; responsiveness to quinpirole decreased with further quinpirole injections. Lack of significant cross-sensitization between bromocriptine and either cocaine or heroin and lack of permanence of the cross-sensitization between bromocriptine and quinpirole raise questions as to the biological basis of psychomotor stimulant sensitization.

Animals↗
PubMed1992

Locomotor-activating effects of the D2 agonist bromocriptine show environment-specific sensitization following repeated injections.

Biphasic effects of bromocriptine (2.0, 5.0, 10.0, and 20.0 mg/kg IP) on locomotion were quantified in photocell activity boxes in rats. Following early suppression of activity, bromocriptine produced a clear, dose-dependent increase in locomotion that lasted several hours. When a low dose of bromocriptine (5.0 mg/kg) was administered daily over a 3-week period, the locomotor-activating effects of the drug showed progressive enhancement over days. The sensitization was environment specific; rats administered bromocriptine six times in the home cage showed no sign of a sensitized response to bromocriptine when subsequently tested in the activity box. Thus, selective stimulation of D2 receptors stimulates locomotion and sensitizes animals to subsequent injections, just as do the indirect-acting dopamine agonists cocaine and amphetamine.

Animals↗
PubMed1993

A randomized trial of bromocriptine for cocaine users presenting to the emergency department.

OBJECTIVE: To determine the practicality of treating heavy cocaine users with bromocriptine in an outpatient setting to reduce cocaine use and increase entry into drug treatment. DESIGN: Double-blind, randomized, placebo-controlled trial. SETTING: VA Medical Center emergency department. PARTICIPANTS: Twenty-nine men presenting for minor medical complaints who used cocaine at least four times per week for the previous month. INTERVENTION: Subjects received either bromocriptine, 1.25 mg, or placebo three times per day for two weeks. MEASUREMENTS AND MAIN RESULTS: On three follow-up visits, subjects were tested for cocaine metabolites and surveyed about their drug use and symptoms. Eight of 14 subjects randomized to the bromocriptine group appeared for follow-up evaluation and seven enrolled in drug treatment. Three of these patients tested negative for cocaine at all three visits. Ten of 15 control patients appeared for follow-up visits and five enrolled in drug treatment. None of the control patients tested negative for cocaine for all three visits. There was no major side effect. CONCLUSION: Bromocriptine can be administered safely to heavy cocaine users in an emergency department setting. The question of whether bromocriptine will reduce the use of cocaine or promote entry into drug treatment deserves further research.

Adult↗
PubMed1987

Immunohistochemical, electron microscopic and morphometric studies of estrogen-induced rat prolactinomas after bromocriptine treatment.

To clarify the effects of bromocriptine on prolactinoma cells in vivo, immunohistochemical, ultrastructural and morphometrical analyses were applied to estrogen-induced rat prolactinoma cells 1 h and 6 h after injection of bromocriptine (3 mg/kg of body weight). One h after treatment, serum prolactin levels decreased markedly. Electron microscopy disclosed many secretory granules, slightly distorted rough endoplasmic reticulum, and partially dilated Golgi cisternae in the prolactinoma cells. Morphometric analysis revealed that the volume density of secretory granules increased, while the volume density of cytoplasmic microtubules decreased. These findings suggest that lowered serum prolactin levels in the early phase of bromocriptine treatment may result from an impaired secretion of prolactin due to decreasing numbers of cytoplasmic microtubules. At 6 h after injection, serum prolactin levels were still considerably lower than in controls. The prolactinoma cells at this time were well granulated, with vesiculated rough endoplasmic reticulum and markedly dilated Golgi cisternae. Electron microscopical immunohistochemistry revealed positive reaction products noted on the secretory granules, Golgi cisternae, and endoplasmic reticulum of the untreated rat prolactinoma cells. However, only secretory granules showed the positive reaction products for prolactin 6 h after bromocriptine treatment of the adenoma cells. An increase in the volume density of secretory granules and a decrease in the volume densities of rough endoplasmic reticulum and microtubules was determined by morphometric analysis, suggesting that bromocriptine inhibits protein synthesis as well as bringing about a disturbance of the prolactin secretion.

Animals↗
PubMed1983

Fate and disposition of bromocriptine in animals and man. II: Absorption, elimination and metabolism.

The disposition and biotransformation of bromocriptine were investigated in mouse, rat, dog, rhesus monkey and man following administration of the drug substance labelled with either tritium or carbon-14. The enteral absorption of bromocriptine was incomplete and amounted to 30-40% of the dose as estimated directly from the sum of biliary and urinary excretion of radioactive compounds in bile duct cannulated rats and monkeys. The main route of elimination was the bile (80-93% of the absorbed dose). Only 1 to 6% of the radioactive dose was recovered in urine of intact animals and man. Extensive biotransformation of bromocriptine is reflected by very complex metabolite profiles in all tested body fluids and by the almost complete absence of parent drug in urine and bile. Of the numerous drug-derived radioactive components seventeen could be identified. In animals the major urinary metabolites were 2-bromo-lysergic acid (7), its amide (3), and the respective isomers at position 8, metabolites 6 and 1. Bromolysergic acid (7) and bromoisolysergic acid (6) accounted for half of the radioactivity in human urine. In rat and monkey bile up to 40% of the radioactivity was associated with metabolites derived from the oxidation (hydroxylation, ring-opening) of the proline fragment (4, 5, 21-24, 29-31). The hydroxylated compounds were present in the form of conjugates with glucuronic acid. These were subsequently deconjugated in the intestine and recovered in the faeces as the free forms. The presence of the parent drug as a major component in rat plasma following intravenous administration and its absence after oral administration indicated that the elimination of bromocriptine proceeded almost entirely by metabolism in the liver. In vitro studies with isolated rat hepatocytes and 10.000 g supernatant of human liver confirmed the in vivo findings. Based on the structures of the identified metabolites it could be concluded that the biotransformation of bromocriptine in man occurred through the same principal pathways as in all investigated animal species.

Animals↗
PubMedDate not supplied

Fate and disposition of bromocriptine in animals and man. I: structure elucidation of the metabolites.

A total of 16 metabolites of bromocriptine could be isolated from rat bile and incubates of rat liver cell preparations using [6-methyl-14C]bromocriptine as substrate. Separation and purification was achieved by reversed-phase liquid chromatography and preparative thin-layer chromatography in conjunction with radioactivity monitoring. Structure elucidation was based on spectroscopic data (UV, IR, NMR, EI- and FD-MS) and the results of amino acid analysis after acid hydrolysis. Based on the identified metabolites four principal transformation process could be described: -Hydrolytic cleavage of the amide bridge leading to the formation of 2-bromolysergic acid amide (3) and 2-bromolysergic acid (7). -epimerization at position 8 of the bromolysergic acid moiety to the iso-derivatives (isobromocriptine, 2-bromo-isolysergic acid (6), its amide (1), etc.) -regiospecific oxidation at position 8' in the proline fragment generating stereoisomeric 8'-hydroxy-bromocriptines (21-24) -further oxidation of the 8'-hydroxylated derivatives by either the introduction of a second hydroxy group at position 9' to give dihydroxylated derivatives (detected as conjugates with glucuronic acid: metabolites 29, 30 and 31), or the opening of the proline ring under formation of the metabolites 4 and 5 containing glutamic acid instead of proline (7', 8'-seco- 8'-carboxy-bromocriptines). It is suggested that the primary and principal metabolic attack occurs at the proline fragment of the drug. In contrast to the biotransformation of ergoline compounds, none of the bromocriptine metabolites detected showed oxidative transformations in the lysergic acid half of the molecule.

Animals↗