Pergolide dosing compliance and factors affecting the laboratory control of equine pituitary pars intermedia dysfunction.

BACKGROUND: Equine pituitary pars intermedia dysfunction (PPID) is treated with daily pergolide therapy. Owner compliance and its effect on PPID control have not been previously investigated. METHODS: Clinical records were searched to identify the sample of animals with PPID treated with pergolide from 2016 to 2019. The signalment was noted and the dose of pergolide received calculated. Animals were classified as compliant (receiving ≥90% of the veterinarian recommended dose of pergolide) or non-compliant, and as controlled (follow-up basal adrenocorticotrophic hormone concentrations within the reference range) or not. RESULTS: In total, 110 animals were included. The majority (85%) were ≥16 years (mean ± SD 19.8 ± 4.4 years); the most common breeds were Cob (18%), Thoroughbred (16%) and Welsh (15%); 37% were female and 63% male. Overall, 48% were compliant and 52% non-compliant. There was no significant effect of compliance on laboratory control. Of those that were compliant, 74% were controlled, while 67% of non-compliant animals were controlled. Univariable analysis revealed a significant (p < 0.001) effect of age and breed on compliance and control, and of sex on control. On multivariable analysis, only age (compliance) and breed (compliance and control) were retained in the final model. CONCLUSION: Only half of animals received the recommended pergolide dose; however, this did not affect laboratory control of PPID.

Effects of pituitary pars intermedia dysfunction and Prascend (pergolide tablets) treatment on endocrine and immune function in horses.

It remains unclear how pituitary pars intermedia dysfunction (PPID) and pergolide treatment (Prascend [pergolide tablets]) affect endocrine and immune function in horses. To evaluate these effects, blood was collected regularly from 28 university-owned horses (10 Non-PPID, 9 PPID control [PC], and 9 PPID treatment [PT]) over approximately 15 mo. Pergolide treatment was initiated after Day 0 collections. Analyses included ACTH, insulin, total cortisol, free cortisol, complete blood counts, plasma myeloperoxidase, and cytokine/receptor gene expression in basal whole blood and in vitro stimulations (PMA/ionomycin, heat-inactivated Rhodococcus equi, and heat-inactivated Escherichia coli) of whole blood and peripheral blood mononuclear cells (PBMCs). The results were analyzed using a linear mixed model (SAS 9.4) with significance set at P < 0.05. Significant group (P = 0.0014) and group-by-time (P = 0.0004) effects were observed in resting ACTH such that PT horses differed from Non-PPID horses only at Day 0. PT horses had significantly lower changes in ACTH responses to thyrotropin-releasing hormone stimulation tests than PC horses at non-fall time points only, mid-late February 2018 (P = 0.016) and early April 2018 (P = 0.0172). When PT and PC horses did not differ, they were combined before comparison to Non-PPID horses. No significant group or group-by-time effects were seen in resting insulin, total cortisol, or free cortisol; however, significant time effects were observed in these measures. PPID horses had lower absolute lymphocyte (P = 0.028) and red blood cell (P = 0.0203) counts than Non-PPID horses. In unstimulated whole blood, PPID horses had increased IL-8 expression compared with Non-PPID horses (P = 0.0102). In addition, PPID horses had decreased interferon γ production from PBMCs after stimulation with R. equi (P = 0.0063) and E. coli (P = 0.0057) and showed increased transforming growth factor ß expression after E. coli stimulation (P = 0.0399). The main limitations of this study were a limited sample size and an inability to truly randomize the PPID horses into treatment groups. Resting ACTH is likely the best choice for determining successful responses to pergolide. Neither PPID nor pergolide appears to influence insulin, total cortisol, and free cortisol. As measured, systemic immune function was altered in PPID horses, and it is likely that these horses are indeed at increased risk of opportunistic infection. Despite reducing ACTH, pergolide treatment did not appear to influence immune function.

Efficacy of pergolide for the management of equine pituitary pars intermedia dysfunction: A systematic review.

Pergolide, a dopamine agonist, is commonly administered to manage pituitary pars intermedia dysfunction (PPID), a progressive neurodegenerative disease prevalent in aged horses. However, available evidence regarding pergolide's efficacy in improving clinical and endocrine parameters is limited. The aim of this systematic review was to assess published literature and evaluate evidence regarding whether pergolide treatment results in improvement of clinical signs and/or adrenocorticotrophic hormone (ACTH) concentration compared to no treatment or other unlicensed treatments. Systematic searches of electronic databases were undertaken in April 2019, repeated in August and October 2019, and updated in July 2020. English language publications published prior to these dates were included. Screening, data extraction and quality assessment of publications was undertaken individually by the authors using predefined criteria and subsequently cross-checked. Modified critically appraised topic data collection forms were used to extract data. Due to marked between-study variations, meta-analysis was not undertaken. After removal of duplicate records; 612 publications were identified, of which 129 abstracts were screened for eligibility and 28 publications met criteria for inclusion in the review. Most studies were descriptive case series, cohort studies or non-randomised, uncontrolled field trials. Despite marked variation in study populations, case selection, diagnostic protocols, pergolide dose, follow-up period and outcome measures, in the vast majority of the included studies, pergolide was reported to provide overall clinical improvement in >75% of cases. However, reported improvements in individual clinical signs varied widely. A reduction in plasma ACTH concentrations was reported in 44-74% of cases, while normalisation to within reported reference intervals occurred in 28-74% of cases.

Pharmacokinetics and pharmacodynamics of pergolide mesylate after oral administration in horses with pituitary pars intermedia dysfunction.

Published information on the pharmacokinetic and pharmacodynamic properties of pergolide is limited. The aim of this study was to investigate the pharmacokinetic and pharmacodynamic properties of oral pergolide in horses with pituitary pars intermedia dysfunction (PPID). The study design was a nonrandomized clinical trial. Six horses with PPID diagnosed by thyrotropin-releasing hormone (TRH) stimulation tests received pergolide at 4 µg/kg for 18 d. Plasma samples for determination of pergolide and ACTH concentration were collected 0.5 h before and 2 and 12 h after each administration of pergolide. Maximum plasma concentrations after the first oral dose of pergolide (0.104-0.684 ng/mL; median 0.261 ng/mL; interquartile range [IQR] 0.184-0.416 ng/mL) were not significantly different to the maximum steady-state concentration at day 18 (0.197-0.628 ng/mL; median 0.274; IQR 0.232-0.458 ng/mL). Chronic administration was not associated with drug accumulation (R = 1.09) and pergolide concentration reached steady state within 3 d. Throughout, concentrations of pergolide fluctuated considerably, with median plasma peak concentrations more than four times higher than median trough concentrations. Plasma ACTH concentration reduced significantly within 12 h of administration with further reductions occurring up to 10 d after the initiation of treatment. Although there were parallel fluctuations in the concentrations of pergolide and ACTH, timing of ACTH measurement in relation to the administration of pergolide did not have a significant effect. Alterations in the response to TRH were identified at 8 d with no further change being identified at 18 d. A small number of horses were studied. Oral pergolide results in significant suppression of pars intermedia activity within hours. Pergolide and ACTH concentrations fluctuated in tandem although correlation was poor. Fluctuations in pergolide concentration were consistent with a terminal elimination half-life of less than 12 h. To reduce the level of fluctuation of ACTH, twice-daily dosing of pergolide may be more appropriate.

Effects of chronic exposure to octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane in the aging female Fischer 344 rat.

Octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) are used as intermediates or monomers in the synthesis of silicon-based polymers for industrial or consumer applications. D4 and D5 may remain as residual monomer in these polymers at less than 1000ppm and may therefore be present as a minor impurity in consumer products. For D5, in addition to the manufacture of polymers, its uses include intentional addition to consumer products, personal care products and some dry- cleaning solvents. Two-year rodent chronic bioassays were conducted with both substances and borderline increases in the incidence of uterine tumors were observed, specifically, benign uterine adenoma with D4 and adenocarcinoma with D5. The effects profile and induction of uterine tumors share some similarity with that seen with chronic exposure to dopamine agonists. The current study investigated the potential for D4 and D5 to elicit dopamine agonist-like effects on estrous cyclicity. Separate groups of reproductively senescent female Fischer 344 rats (F344) were exposed via vapor inhalation to D4 (700ppm, 9.3mg/L) or D5 (160ppm, 2.1mg/L) or to a diet containing 0.0045, 0.045, or 4.5ppm pergolide mesylate (PM), a potent dopamine agonist used here as a reference substance, from 11 through 24 months of age. The primary focus was to characterize the effects of D4 and D5 exposure on estrous cyclicity relative to that observed with PM. As a monitoring effort, circulating endogenous estradiol, progesterone, prolactin and corticosterone levels were evaluated monthly. A blood sample from each rat was obtained via tail vein in the afternoon after the daily inhalation exposure period once every 4 weeks. Histomorphologic examination of the major organs including the reproductive tract was conducted on all animals at study termination. This study has shown that chronic exposure to D4 and D5 can affect cyclicity in the reproductively senescent F344 rat. For each substance the effect on cyclicity involved reduction in the incidence of pseudopregnancy with a shift toward cycles more typical of younger animals. D4 and D5 induced an increase in estrous cycle repetition whereas D4 also increased the incidence of extended estrus. These shifts resulted in animals entering proestrus/estrus significantly more times over the duration of the study than seen in the control group. Similar effects were observed with the reference substance, PM. However, distinct differences in the timing and magnitude of the effects on the estrous cycle and impact on prolactin, progesterone, estradiol, and corticosterone suggest that D4 and D5 are not classical dopamine agonists even though a similar increased incidence of proestrus/estrus was also observed with PM. These results may prove important with respect to understanding D4- and D5-induced uterine tumor response in the F344 rat, given the relationship between increased incidence of uterine endometrium stimulation by endogenous estrogen as a consequence of extended or more frequent proestrus/estrus, uterine tumor risk, and questions of relevance to humans. Recent publications have summarized the existing data on D4 and D5, with emphasis on exploring the biological relevance of the uterine tumors (Klaunig et al., 2016a,b; Franzen et al., 2017; Dekant and Klaunig, 2016; Dekant et al., 2017). The authors concluded that although the mode of action has not yet been fully established, the data, including the findings from this study, indicate that the D4- and D5-induced uterine tumors observed in the rodent chronic bioassays have no relevance for human risk characterization based not only on the distinct species differences in regulation of the reproductive systems, but also the high exposure levels and duration required for expression in rats.

Pharmacokinetic and pharmacodynamic properties of pergolide mesylate following long-term administration to horses with pituitary pars intermedia dysfunction.

The objective of this study was to gain an understanding of the pharmacokinetic and pharmacodynamic properties of pergolide in horses with PPID after of long-term oral administration. Six horses with confirmed PPID were treated with pergolide (Prascend® ) at 1 mg/horse po q24 h for 2 months, followed by 2 mg/horse po q24 h for 4 months. Following the last dose, plasma samples were collected for measurement of pergolide using an LC/MS/MS method and ACTH measurement using a chemiluminescent immunoassay. Noncompartmental and compartmental pharmacokinetic analyses were performed, as well as pharmacodynamic assessment of the effect of plasma pergolide concentrations on plasma ACTH concentrations. Pergolide effectively decreased plasma ACTH concentration in aged horses with PPID, with similar pharmacokinetic properties as reported in young horses, including an approximate terminal half-life of 24 h. Plasma ACTH concentration increased by 50% in 3/6 horses at 2 days and 6/6 horses 10 days after discontinuing drug administration. Pergolide was quantified in all horses at 2 days and in none at 10 days after last dose. In summary, after discontinuing pergolide treatment, plasma ACTH concentration increased while pergolide was still quantifiable in some horses. Once-daily dosing of pergolide is likely appropriate in most horses with PPID for regulating the plasma ACTH concentration.

Pharmacokinetics of pergolide after intravenous administration to horses.

OBJECTIVE: To determine the pharmacokinetics of pergolide after IV administration to horses. ANIMALS: 8 healthy adult horses. PROCEDURES: Pergolide mesylate was administered IV at a dose of 20 µg/kg (equivalent to 15.2 µg of pergolide/kg) to each horse, and blood samples were collected over 48 hours. Pergolide concentrations in plasma were determined by means of high-performance liquid chromatography-tandem mass spectrometry, and pharmacokinetic parameters were determined on the basis of noncompartmental methods. RESULTS: After IV administration of pergolide, mean ± SD clearance, elimination half-life, and initial volume of distribution were 959 ± 492 mL/h/kg, 5.64 ± 2.36 hours, and 0.79 ± 0.32 L/kg, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: With an elimination half-life of approximately 6 hours, twice-daily dosing may be more appropriate than once-daily dosing to reduce peak-trough fluctuation in pergolide concentrations. Further pharmacodynamic and pharmacokinetic studies of pergolide and its metabolites will be necessary to determine plasma concentrations that correlate with clinical effectiveness to determine the therapeutic range for the treatment of pituitary pars intermedia dysfunction.

Efectividad y seguridad de Pramipexol comparado con Levodopa, Pergolida, Cabergolina, Ropinirole para el tratamiento del Síndrome de Piernas Inquietas / Effectiveness and safety of Pramipexole compared to Levodopa, Pergolide, Cabergoline, Ropinirole for the treatment of Restless Legs Syndrome

IIntroducción: el Síndrome de Piernas Inquietas (SPI) se define como un trastorno neurológico que afecta de un 5 % a un 15% de la población general, de causa desconocida, incurable y de evolución crónica, con afectación del sueño y la calidad de vida en alerta. Se cuenta con tratamientos para aliviar los síntomas que afectan la calidad de vida, una primera línea de tratamiento son los agonistas dopaminérgicos entre ellos la Levodopa, el Pramipexol y la Pergolida (8), (9), (10). Objetivo: evaluar la efectividad y seguridad del pramipexol, comparado con otros agonistas dopaminergicos para el tratamiento del Síndrome de Piernas Inquietas (RSL). Metodología: la evaluación fue realizada de acuerdo al protocolo definido previamente por el grupo desarrollador el cual incluye una revisión sistemática de la literatura en MEDLINE, EMBASE, LILACS, COCHRANE y Google para dar respuesta a la pregunta de investigación desarrollada bajo la estrategia PICOT en compañía de expertos técnicos y metodológicos. En el estudio de Scholz con el uso del pramipexol se observó una diferencia de medias de -5.16 [IC95% -6.87 a -3.45] comparado con placebo en la escala de síntomas IRLS (I²= 76%). Los agonistas dopaminérgicos comparados con el placebo produjeron una diferencia de medias en la reducción del PLMSI de −22.38 (IC95% −27.82 a −16.94) por hora de sueño (I² = 73%). El Pramipexol produjo contra placebo una diferencia de medias de -30.47 [IC9% -51.58 a -9.35] (I² = 85%) en el Cambio en el PLMSI (calidad del sueño, a favor de pramipexol. Los agonistas dopaminérgicos comparados con placebo reportaron una diferencia de medias de 0.4 [IC95% 0.33 a 0.47] a favor de los agonistas dopaminergicos respecto a la calidad del sueño autoreportada. En un análisis de subgrupos por medicamentos, el pramipexol produjo contra placebo un cambio en la calidad del sueño autoreportada con una diferencia de medias de 0.44 [IC: 0.33, 0.54], a favor de pramipexol. Los agonistas dopaminérgicos produjeron mejoría en la calidad de vida comparado contra placebo con una diferencia de medias de 0.34 [IC95% 0.23 a 0.44] (I²= 61%). En un análisis de subgrupos por medicamento, el pramipexol produjo mejoría en la calidad de vida comparado contra placebo con una diferencia estandarizada de medias de 0.30 [IC95% 0.13 a 0.47]. Los agonistas dopaminérgicos (cabergolina o pramipexol) comparados con levodopa produjeron un cambio en la línea de base del IRLS con una diferencia de medias de -5.25 [IC95% -8.40 a -2.10] (I²= 55%). En comparaciones indirectas dentro del estudio Ying Sun el pramipexol versus el ropirinole mostró una diferencia de medias en la escala de síntomas IRLS de -1.48 (IC95% -4.47 a 0.45) sin embargo esta diferencia no fue estadísticamente significativa. Respecto a la seguridad, los eventos adversos fueron más frecuentes en el grupo de pacientes que recibió agonistas dopaminérgicos comparado con los pacientes que recibieron placebo con un OR de 1.82 [IC95% 1.59 a 2.08]. Los retiros por eventos adversos fue superior en el grupo de agonistas dopaminergicos versus placebo, con un OR 1.82, (IC95% 1.35 a 2.45), diferencia estadísticamente significativa y mostró una heterogeneidad moderada (I² = 41%). Los retiros por eventos adversos fue superior en el grupo de agonistas dopaminergicos versus placebo, con un OR 1.82, (IC95% 1.35 a 2.45), diferencia estadísticamente significativa y mostró una heterogeneidad moderada (I² = 41%). En un análisis de subgrupos por medicamentos, se reportaron más retiros con pramipexol que con placebo con un OR de 1.11 [IC95% 0.66 a 1.87], esta diferencia no fue estadísticamente significativa con una heterogeneidad moderada (I²= 44%). Conclusiones: Efectividad: Los agonistas dopaminergicos, dentro de los cuales está incluido el pramipexol, son más efectivos que el placebo en el tratamiento de las personas con RLS para los desenlaces de escala de síntomas IRLS, la reducción del PLMSI , la calidad de sueño autoreportada y calidad de vida. En un análisis por subgrupos dentro de la comparación entre agonistas dopaminergicos y el placebo, el pramipexol se mostró más efectivo que el placebo en los desenlaces del cambio del PLMSI, calidad del sueño y en la calidad de vida. Los agonistas dopaminergicos, dentro de los cuales está incluido el pramipexol, son más efectivos que la levodopa para los desenlaces de escala de síntomas IRLS. Al comparar el pramipexol de forma indirecta con el ropirinole (agonista dopaminergico) no se observaron diferencias estadísticamente significativas. Seguridad: Los eventos adversos son más frecuentes en el de grupo tratamiento con agonistas dopaminergicos (dentro de los cuales se encuentra el pramipexol) comparado con placebo. No se encontraron diferencias en seguridad entre el pramipexol y el placebo.(AU)

Evaluation of the efficacy of pramipexole for treating levodopa-induced dyskinesia in patients with Parkinson's disease.

OBJECTIVE: The long-term use of levodopa to treat Parkinson's disease (PD) is often limited by the development of motor complications (e.g., levodopa-induced dyskinesia, LID). We hypothesized that a non-ergot dopamine agonist with strong affinity for D3) dopamine receptors (pramipexole) may improve LID in patients taking an ergot D1/D2 dopamine agonist. METHODS: Patients with PD and LID being treated with levodopa in addition to an ergot dopamine agonist were randomized to either a group in which pramipexole was added to current medications or a group in which the ergot dopamine agonist was switched to pramipexole. Dyskinesia was evaluated using Core Assessment Program for Surgical Interventional Therapies scores. The unified Parkinson's disease rating scale scores, modified Hoehn and Yahr stages (at 'on' time), Parkinson's disease questionnaire-39 scores and clinical global impression-improvement scores were also used for evaluation. RESULTS: At 24 weeks, pramipexole alleviated LID with more efficiency in the switch group. CONCLUSION: Pramipexole may be a therapeutic option for treating LID because its effects on D3 dopamine receptors may balance the D1 dopamine receptor supersensitivity associated with LID.

Valvular heart disease in patients exposed to pergolide: insights from the clinical presentation.

PURPOSE: The aim of this study was to determine whether the presence of symptoms would aid in the detection of valvular heart disease (VHD) in those exposed to pergolide. METHODS: Utilizing a prospective, cross-sectional study design, patients with an exposure to pergolide were asked regarding the presence or absence of chest pain, shortness of breath or lower extremity edema through a questionnaire. Echocardiograms were obtained on the same day as the questionnaire and were blinded to all staff involved in the study. The sensitivity, specificity, positive and negative predictive value of the reported symptoms towards the outcome moderate or severe valvular regurgitation were obtained. Using the area under the receiver-operating characteristic curve, we also ascertained whether a relationship existed between symptoms, pergolide dose and presence of VHD. To understand the associations between symptoms and echocardiographic covariates, a logistic regression analysis was performed adjusted for age and gender. RESULTS: The sensitivity, specificity, positive and negative predictive value of symptom presentation and total dose was sufficiently low that it did not aid in the determination whether significant valvular regurgitation was present. Multivariable analysis noted a significant association with indexed left atrial volume (p = 0.011), estimated pulmonary artery pressure (p = 0.047) and shortness of breath. CONCLUSIONS: The presence or absence of symptoms does not help guide whether valvular regurgitation is present or absent in individuals exposed to pergolide. Therefore, echocardiography is needed to confirm or refute pergolide-associated VHD.

Reversal of long-term methamphetamine sensitization by combination of pergolide with ondansetron or ketanserin, but not mirtazapine.

Psychostimulant abuse represents a psychiatric disorder and societal concern that has been largely unamenable to therapeutic interventions. We have previously demonstrated that the 5-HT3 antagonist ondansetron or non-selective 5-HT(2A/2C) antagonist ketanserin administered 3.5 h following daily pergolide, a non-selective DA agonist, reverses previously established cocaine sensitization. The present study was conducted to evaluate whether the same treatments or delayed pairing of pergolide with the antidepressant mirtazapine can also reverse consolidated methamphetamine (METH) behavioral sensitization. Sprague-Dawley rats received METH infusion via osmotic minipumps (25 mg/kg/day, s.c.) for 7 days, with accompanying daily injections of escalating METH doses (0-6 mg/kg, s.c.). This regimen takes into account the faster elimination of METH in rats, and is designed to replicate plasma METH concentrations with superimposed peak drug levels as observed during METH binging episodes in humans. Following a 7-day METH withdrawal, ondansetron (0.2 mg/kg, s.c.), ketanserin (1.0 mg/kg, s.c.), or mirtazapine (10mg/kg, i.p.) was administered 3.5 h after pergolide injections (0.1 mg/kg, s.c., qd) for 7 days. Behavioral sensitization as a model of METH abuse was assessed 14 days after the combination treatment cessation (i.e., day 28 of METH withdrawal) through an acute challenge with METH (0.5 mg/kg, i.p.). Pergolide combined with ondansetron or ketanserin reversed METH behavioral sensitization, but pergolide-mirtazapine combination was ineffective. The role of reactivation of addiction "circuit" by a non-selective DA agonist, and subsequent reconsolidation blockade through 5-HT3 or 5-HT2 antagonism in reversal of METH sensitization and treatment of METH addiction is discussed.

Restless legs syndrome (RLS) augmentation associated with dopamine agonist and levodopa usage in a community sample.

OBJECTIVE: Assess the rate of augmentation as it occurs during standard long-term dopaminergic treatment of RLS, potential risk factors or predictors of augmentation, the relationship between treatment duration and augmentation, and the clinical impact of augmentation on subjects' health outcomes. METHODS: Two hundred sixty-six patients with dopamine-treated RLS completed a one-time online survey. All subjects were recruited by their PCP/neurologist and were 18 or older. Augmentation was assessed using NIH guidelines and an augmentation classification system was developed through this research. RESULTS: Overall, 20% of the patients were classified as having definitive or highly suggestive clinical indications of augmentation. Five factors were considered likely to reflect increased risk of developing augmentation, including more frequent RLS symptoms pre-treatment, greater discomfort with RLS symptoms before treatment, and longer treatment duration. RLS augmentation occurred at a rate of about 8% each year for at least the first 8 years of dopamine treatment. Subjects reporting definite or highly suggestive clinical indicators of augmentation had an average IRLS score of 23.6, indicating generally inadequate treatment with generally poor clinical outcomes. Only 25% of the patients reported no indications of augmentation and they were the only group to show on average a low (<15) IRLS score and good clinical outcomes. CONCLUSIONS: As currently used, long term dopaminergic treatment for an average ± SD of 2.7 ± 2.4 years produced significant augmentation problems in at least 20% of the patients and only 25% of the patients were totally free of this problem. It is important for physicians to carefully screen patients for changes in RLS symptoms for as long as they are on dopamine agents, with particular attention paid to those patients who present with the most severe RLS symptoms prior to treatment initiation. Given the marked increase in suffering with augmentation, a method for early detection and intervention would be an important contribution to the effective management and treatment of RLS.

The impact in Japan of regulatory action on prescribing of dopamine receptor agonists: analysis of a claims database between 2005 and 2008.

BACKGROUND: Use of the ergot-derived dopamine receptor agonists (cabergoline and pergolide) is associated with an increased risk of cardiac valvulopathy. Pergolide was withdrawn from the US market in 2007 because of the risk of valvular heart disease, while the European Medicines Agency (EMA) required a reduction in the maximum daily dosage of cabergoline and pergolide from 6 mg/day to 3 mg/day in 2008. In Japan, the package inserts of both drugs were revised in April 2007 to request that physicians conduct periodic ultrasonic cardiography (UCG) examinations for patients taking cabergoline or pergolide. Also, through face-to-face communication with medical representatives of drug companies, physicians were informed that use of cabergoline and pergolide has increased the risk of valvulopathy. However, cabergoline and pergolide have remained in wide use, even following the regulatory actions. OBJECTIVE: The objective of this study was to assess the impact of actions, including the package insert revision in April 2007, to encourage periodic UCG. METHODS: Data on monthly claims (January 2005-October 2008) covering 330 000 patients were obtained from a Japanese database vendor. We selected patients ≥40 years of age with Parkinson's disease. The impact of the regulatory action on the proportion of patients with Parkinson's disease prescribed cabergoline or pergolide was assessed by segmented regression analysis and by a statistical model of the rates of UCG examination in patients taking/not taking cabergoline or pergolide before and after the action. We also compared the use of cabergoline and pergolide before and after the action with that of other antiparkinson drugs. RESULTS: Of 574 patients with Parkinson's disease, the proportion of patients prescribed cabergoline or pergolide did not decrease but rather tended to increase after the action when analysed by segmented regression analysis (p = 0.13). Similarly, the proportion of the prevalent and incident users of cabergoline or pergolide did not change between two 19-month periods before and after the action. The adjusted rates of UCG examination per person-year before and after the action were both 0.02 in those not prescribed cabergoline or pergolide, but 0.02 before the action and 0.09 after the action in those taking either drug. The excess UCG examination rate of cabergoline or pergolide attributable to the action was 0.08 per person-year (95% CI 0.03, 0.11). While 1 of 49 (2%) patients taking cabergoline or pergolide had a UCG up to 19 months before the action, 9 of 36 (25%) patients taking cabergoline or pergolide had a UCG up to 19 months after the action. Annual sales from 2004 to 2008 were 195, 195, 170, 110 and 75 billion yen, respectively, and the number of valvulopathy events, including incompetence of aortic/mitral/tricuspid valves and cardiac valve disease, per annual sales from 2004 to 2008 were estimated at 0.23, 0.03, 0.08, 0.25 and 0.19 per billion yen, respectively. CONCLUSIONS: Following the actions in April 2007, no decrease in the use of cabergoline or pergolide occurred, although more patients administered the drug underwent a UCG. However, those undergoing a UCG represented one-quarter of the total number prescribed cabergoline or pergolide. To mitigate the risk, additional risk management tools such as patient registration may be needed to secure careful clinical examination (including UCG examination, if necessary) for cardiac function.

Dopaminergic stimulation enhances confidence and accuracy in seeing rapidly presented words.

Liberal acceptance, overconfidence, and increased activity of the neurotransmitter dopamine have been proposed to account for abnormal sensory experiences, for instance, hallucinations in schizophrenia. In normal subjects, increased sensory experience in Yoga Nidra meditation is linked to striatal dopamine release. We therefore hypothesize that the neurotransmitter dopamine may function as a regulator of subjective confidence of visual perception in the normal brain. Although much is known about the effect of stimulation by neurotransmitters on cognitive functions, their effect on subjective confidence of perception has never been recorded experimentally before. In a controlled study of 24 normal, healthy female university students with the dopamine agonist pergolide given orally, we show that dopaminergic activation increases confidence in seeing rapidly presented words. It also improves performance in a forced-choice word recognition task. These results demonstrate neurotransmitter regulation of subjective conscious experience of perception and provide evidence for a crucial role of dopamine.

A 10-year, longitudinal assessment of dopamine agonists and methadone in the treatment of restless legs syndrome.

BACKGROUND: Restless legs syndrome (RLS) is a chronic disease, which is managed with palliative medications that are likely to be required for a patient's lifetime. It is, therefore, important to know the long-term consequences of these treatments. Currently, the most commonly prescribed treatment for RLS is one of the dopamine (DA) agonists. Most of what we understand about efficacy and side effects of the DA agonists are, however, derived from relatively short-term studies. This is particularly a problem since these medications produce in some patients a significant increase or augmentation of RLS symptoms known to occur during the first 2 years of treatment and perhaps even later in treatment. The primary aim of this study was to determine the long-term efficacy (10-year) for commonly used RLS medication types: dopaminergic agonists and opioids. METHODS: Records of all RLS patients treated in one tertiary care center with pramipexole, pergolide or methadone during the years 1997-2007 were reviewed. The duration and reason for any discontinuation of treatment and medication doses were recorded. RESULTS: Annual rates for discontinuing treatment persisted for up to 10 years of treatment and were fairly constant after the first year at 9% for pramipexole, 8% for pergolide, and 0% for methadone. Similarly, annual augmentation rates were fairly constant after the first year and persisted for up to 10 years at 7% for pramipexole, 5% for pergolide, and 0% for methadone. The percentage continuing on the treatment medication for over 5 years was 58% for pramipexole and 35% for pergolide. CONCLUSIONS: The DA agonists appear to have a limited period of clinical utility for many patients. Severe augmentation, while not common in any 1 year, can develop even after years on the medication. Methadone, in contrast, shows neither augmentation nor major problems with continued efficacy after the first year of treatment.

Single-dose oral pharmacokinetics of pergolide mesylate in healthy adult mares.

Pituitary pars intermedia dysfunction (PPID) is probably the most common disease of geriatric horses. Affected horses show a variety of clinical signs, including hirsutism, polyuria/polydipsia, immunosuppression, muscle wasting, and laminitis. The most common treatment for PPID is pergolide, a dopamine agonist; however, there are no pharmacokinetic data about the use of this drug in horses. This article describes a study designed to address this complete lack of pharmacokinetic information. The pharmacokinetics of pergolide are described in a small group of relatively young, healthy mares (n = 6), with the objective of generating data on which to base larger studies in the future. To make definitive dosing recommendations to clinicians, more studies will be needed to investigate the relationship between plasma pergolide concentrations and clinical outcomes, as well as the effect of gender, age, and concomitant disease on the absorption and disposition of this drug.

Pergolide treatment of cognitive deficits associated with schizotypal personality disorder: continued evidence of the importance of the dopamine system in the schizophrenia spectrum.

Cognitive deficits observed in schizophrenia are also frequently found in individuals with other schizophrenia spectrum disorders, such as schizotypal personality disorder (SPD). Dopamine appears to be a particularly important modulator of cognitive processes such as those impaired in schizophrenia spectrum disorders. In a double-blind, placebo-controlled clinical trial, we administered pergolide, a dopamine agonist targeting D(1) and D(2) receptors, to 25 participants with SPD and assessed the effect of pergolide treatment, as compared with placebo, on neuropsychological performance. We found that the pergolide group showed improvements in visual-spatial working memory, executive functioning, and verbal learning and memory. These results suggest that dopamine agonists may provide benefit for the cognitive abnormalities of schizophrenia spectrum disorders.

Effects of pergolide mesilate on metallothionein mRNAs expression in a mouse model for Parkinson disease.

Dopamine agonists have neuroprotective properties in addition to their original pharmacologic function. We examined the effects of pergolide mesilate (PM) on the levels of metallothionein mRNA expression and lipid peroxidation in the corpus striata of 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonian mice. Mice were administered normal saline (vehicle as a control), PM, or MPTP. A consecutive 7-d administration of MPTP via a gastric tube at a dose of 30 mg/kg significantly decreased metallothionein (MT)-I mRNA expression but did not influence MT-III mRNA expression. Lipid peroxidation, measured as the production of malondialdehyde reactive substances, did not increase after MPTP treatment. Although PM administration alone did not effect MT-I expression, an additional consecutive 7-d administration of PM (30 mug/kg) following MPTP treatment recovered the decreased MT-I level and increased MT-III expression. Lipid peroxidation was significantly suppressed. These results suggest that PM exerts an antioxidative property through the induction of MT-I and MT-III mRNAs simultaneously in response to cellular and/or tissue injury.