Constrictive pericarditis and pleuropulmonary disease linked to ergot dopamine agonist therapy (cabergoline) for Parkinson's disease

Surgery is a safe, effective first-line treatment modality for noninvasive prolactinomas

PURPOSE

Dopamine agonists (DAs) have long been the recommended first-line treatment for prolactinoma. Given the remarkable developments in surgical techniques, however, surgery is on the rise. We compared the treatment outcomes of patients with noninvasive prolactinomas receiving two different initial treatments (DAs and transsphenoidal surgery).

METHODS

We reviewed 745 patients with hyperprolactinemia or pituitary tumors treated from 2004 to 2020 at Chonnam National University Hwasun Hospital and identified 310 with prolactinomas. After selecting patients who had pituitary tumors with Knosp grade 0 to 1 with follow-up period over 1 year, 70 patients (29 who underwent surgery and 41 who received DAs as the initial treatment) were finally included for a comparative study.

RESULTS

The surgery group exhibited better outcomes in terms of DA-free remission and the structural response, although the tumor size was significantly larger than in the DA group. The groups exhibited comparable results in terms of symptom control and the biochemical response. Univariate and multivariate analyses indicated that surgery as the initial treatment modality provided significantly better clinical outcomes in terms of DA-free remission. In the surgery group, a postoperative prolactin level < 10 ng/mL was the only significant predictor of DA-free remission.

CONCLUSIONS

Transsphenoidal surgery showed comparable clinical outcomes in patients with prolactinomas, and low complication rates. The decision regarding the first-line treatment modality for non-invasive prolactinomas should be made on an individual basis.

Factors to Consider in the Selection of Dopamine Agonists for Older Persons with Parkinson's Disease

Dopamine agonists (DAs) are frequently used in the management of Parkinson's disease (PD), a complex multisystem disorder influenced substantially by age-related factors. Over 80% of PD patients present after age 60 years and may have clinical features exacerbated by age-related comorbidities or decline in physiological compensatory mechanisms. Pharmacotherapy for motor symptoms in older persons is more likely to involve exclusive use of levodopa combined with a peripheral decarboxylase inhibitor throughout the course of the illness. Non-ergot DAs, such as pramipexole, rotigotine and ropinirole, may be used as de novo monotherapy for the control of motor symptoms in older persons, although they are less efficacious than levodopa therapy. DAs may also be considered as adjunct therapy in older persons when motor symptoms are no longer adequately controlled by levodopa or when motor fluctuations and dyskinesia appear. DAs may be used cautiously in older persons with cognitive impairment and orthostatic hypotension but should be avoided when there is a history or risk of psychosis or impulse control disorders.

Cabergoline in acromegaly

Acromegaly, a rare disease due to growth hormone (GH) hypersecretion by a pituitary adenoma, is associated with severe comorbidity and premature death if not adequately treated. The usual first-line treatment is surgery. Various drugs, including somatostatin receptor ligands, dopamine agonists and GH receptor antagonists, are now available for use if surgery fails to suppress GH/IGF-I hypersecretion. Cabergoline, now the preferred dopamine agonist for treating hyperprolactinemia, is also used off-label for treating acromegaly. Cabergoline monotherapy is reported to normalize IGF-I levels in more than one-third of patients with acromegaly. When a somatostatin receptor ligand proves ineffective, cabergoline add-on therapy normalizes the IGF-I level in 40-50% of patients. Finally, when combined with the GH receptor antagonist pegvisomant in patients with mild uncontrolled disease, cabergoline helps to achieve normal IGF-I levels while avoiding the need for high-dose pegvisomant. Cabergoline is also inexpensive and well tolerated; in particular, it does not appear to promote heart valve disease.

Drug treatment of Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disease. While its cause remains elusive, much progress has been made regarding its treatment. Available drugs have a good symptomatic effect, but none has yet been shown to slow the progression of the disease in humans. The most efficacious drug is levodopa, but it remains unclear whether the symptomatic benefit is associated with neurotoxic effects and long-term deterioration. The long-term problem associated with levodopa is the appearance of dyskinesias, which is significantly delayed among patients treated with dopamine agonists as initial therapy. Less clear is the role of other drugs in PD, such as monoamine oxidase inhibitors (MAOIs), including selegiline and rasagiline, the putative N-meihyl-o-aspartaie (NMDA) receptor antagonists amantadine and memantine, and the muscarinic receptor blockers. All these may be used as initial therapy and delay the use of dopaminergic drugs, or can be added later to reduce specific symptoms (tremor or dyskinesias). Advanced PD is frequently associated with cognitive decline. To some extent, this can be helped by treatment with cholinesterase inhibitors such as rivastigmine. Similarly, hallucinations and delusions affect PD patients in the advanced stages of their disease. The use of classical neuroleptic drugs in these patients is contraindicated because of their extrapyramidal effects, but atypical drugs, and particularly clozapine, are very helpful. The big void in the therapy of PD lies in the more advanced stages. Several motor symptoms, like postural instability, dysphagia, and dysphonia, as well as dyskinesias, are poorly controlled by existing drugs. New therapies should also be developed against autonomic symptoms, particularly constipation.

Dopamine receptor agonists for the treatment of early or advanced Parkinson's disease

Dopamine receptor agonists are indicated for the symptomatic treatment of early, moderate or advanced Parkinson's disease as well as for the reduction of levodopa-related motor complications. Ergolinic dopamine agonists, such as bromocriptine or pergolide, were initially developed and marketed, and then non-ergolinic dopamine agonists, such as pramipexole and ropinirole, were introduced, reducing the risk of drug-induced fibrotic reactions. Once-daily, controlled-release oral and transdermal formulations have been developed aiming at providing more stable 24-hour plasma drug concentrations and more convenient administration. A disease-modifying effect of dopamine agonists has not been demonstrated clinically. As with any other drug, dopamine agonists can also cause adverse drug reactions, which can be related or unrelated to dopaminergic hyperactivation. Dopaminergic reactions include nausea, hallucinations, confusion and orthostatic hypotension, among others, which were readily identified in pre-marketing clinical trials. During post-marketing surveillance, important adverse reactions were identified, such as daytime somnolence, impulse-control disorders and heart valve fibrosis. Other issues, including the efficacy of dopamine agonists for the treatment of non-motor symptoms, remain under evaluation.

Absence of major fibrotic adverse events in hyperprolactinemic patients treated with cabergoline

BACKGROUND

Cabergoline, a dopamine agonist used to treat hyperprolactinemia, is associated with an increased risk of fibrotic adverse reactions, e.g. cardiac valvular fibrosis, pleuropulmonary, and retroperitoneal fibrosis.

OBJECTIVE

This study evaluated the prevalence and risk of fibrotic adverse reactions during cabergoline therapy in hyperprolactinemic and acromegalic patients.

DESIGN

A cross-sectional study was conducted in a University Hospital.

PATIENTS

A total of 119 patients with hyperprolactinemia and acromegaly who were on cabergoline therapy participated in the study.

METHODS

All patients were requested to undergo a cardiac assessment, pulmonary function test, chest X-ray, and blood tests as recommended by the European Medicine Agency. Matched controls were recruited to compare the prevalence of valvular regurgitation. Cardiac valvular fibrosis was evaluated by assessing valvular regurgitation and the mitral valve tenting area (MVTa). The risk of pleuropulmonary fibrosis was assessed by a pulmonary function test, a chest X-ray, and if indicated, by additional imaging studies.

RESULTS

The prevalence of clinically relevant valvular regurgitation was not significantly different between cases (11.3%) and controls (6.1%; P=0.16). The mean MVTa was 1.27+/-0.17 and 1.24+/-0.21 cm(2) respectively (P=0.54). Both valvular regurgitation and the MVTa were not related to the cumulative dose of cabergoline. A significantly decreased pulmonary function required additional imaging in seven patients. In one patient, possible early interstitial fibrotic changes were seen. Lung function impairment was not related to the cumulative cabergoline dose.

CONCLUSION

Cabergoline, typically dosed for the long-term treatment of hyperprolactinemia or acromegaly, appears not to be associated with an increased risk of fibrotic adverse events.

Pleuropulmonary Toxicity of Another Anti-Parkinson's Drug: Cabergoline

Many drugs may cause toxic injury to the lungs and the pleura. Cabergoline is an ergoline derivative which has been used in Spain for seven years to control symptoms of Parkinson's disease. We report a patient with dyspnea, bilateral pleural effusion and distal swelling. After a series of complementary tests (blood analysis, chest CT, echocardiogram, pleural tap, pleural biopsy), etiological screening ruled out infection, malignancy or inflammation. Given the patient's history of three years' treatment with cabergoline, the drug was considered a possible cause and was progressively withdrawn. The patient's clinical condition improved and radiological images were disease-free. Using Karch and Lasagna's classical criteria, we defined a relationship of "probable causality" between the drug and the adverse effects reported.

Clinical risk-benefit assessment of dopamine agonists

Dopamine agonists (DAs) have proven efficacy as monotherapy in early Parkinson's disease (PD) for preventing motor complications such as dyskinesia and as adjunct therapy as the disease progresses. Further, it is increasingly evident that at least some DAs may provide additional benefits, such as reduction in depressive symptoms and treatment of refractory tremor. Different side-effect profiles have been associated with levodopa and ergot or non-ergot DA treatment, such as sudden onset of sleep, reduced impulse control, hallucination, and cardiovascular fibrosis. This paper discusses the evidence for specific associations between particular treatments and side effects as well as the clinical implications for patient care. Ultimately, the choice depends on the risk-benefit assessment as it applies to the individual patient's clinical profile and the physician's preference.

A case of constrictive pericarditis during cabergoline treatment for hyperprolactinaemia

OBJECTIVE

Treatment with dopamine agonists has been associated with cardiopulmonary fibrotic reactions, predominantly in patients treated for Parkinson's disease. To our knowledge, these reactions have previously not been associated with low-dose cabergoline treatment for hyperprolactinaemia.

METHOD

A case of constrictive pericarditis in a patient treated with cabergoline for hyperprolactinaemia is presented. The patient has been treated at a county hospital and a university hospital in southern Sweden.

RESULTS

A 20-year-old woman with a 3-year history of amenorrhoea was referred to the department in 1992. From 2001 to 2005, she was given cabergoline, 0.5-1.5 mg/week. In 2005 a pericardectomy was performed due to fibrotic, constrictive pericarditis.

CONCLUSIONS

Our present case suggests that constrictive pericarditis may develop even on low-dose cabergoline, which might indicate that this reaction, as opposed to valvular fibrosis, is not mediated by a 5-HT(2B) agonistic mechanism.

Cabergoline-associated erythema nodosum

OBJECTIVE

To report a case of erythema nodosum (EN) and related inflammatory arthropathy in a patient on cabergoline therapy for a microprolactinoma.

CASE SUMMARY

A 25-year-old white female, who had been receiving cabergoline 0.5 mg orally once per week for the preceding 2 months for a microprolactinoma, developed classic skin lesions of EN (proved by histology) and an associated acute inflammatory arthropathy of her left ankle joint in the absence of any other identifiable causes of EN. She improved substantially (skin lesions of EN and inflammatory arthropathy disappeared) after cessation of cabergoline therapy. Rechallenge with cabergoline in a lower dose of 0.25 mg orally once per week led to a milder recurrence of EN lesions that once again disappeared after withdrawal of the drug. She had not had a recurrence at a 3 month follow-up visit.

DISCUSSION

Although possible autoimmune adverse effects (pleuropulmonary and cardiac) have been reported with the use of cabergoline, to the best of our knowledge, this is the first case report of EN (panniculitis) associated with cabergoline therapy. Causality assessment using the Naranjo probability scale revealed that the adverse drug event was probable.

CONCLUSIONS

Cabergoline was probably associated with EN (panniculitis) and the related arthritis in a patient being treated for a microprolactinoma. Panniculitis, like EN, needs to be considered a possible but reversible adverse effect of cabergoline therapy for microprolactinoma of the pituitary gland.

Heart failure induced by non-cardiac drugs

Although heart failure is predominantly caused by cardiovascular conditions such as hypertension, coronary heart disease and valvular heart disease, it can also be an adverse reaction induced by drug therapy. In addition, some drugs have the propensity to adversely affect haemodynamic mechanisms in patients with an already existing heart condition. In this article, non-cardiac drugs known to be associated with the development or worsening of heart failure are reviewed. Moreover, drugs that may adversely affect the heart as a pump without causing symptoms or signs of heart failure are also included. The drugs discussed include anticancer agents such as anthracyclines, mitoxantrone, cyclophosphamide, fluorouracil, capecitabine and trastuzumab; immunomodulating drugs such as interferon-alpha-2, interleukin-2, infliximab and etanercept; antidiabetic drugs such as rosiglitazone, pioglitazone and troglitazone; antimigraine drugs such as ergotamine and methysergide; appetite suppressants such as fenfulramine, dexfenfluramine and phentermine; tricyclic antidepressants; antipsychotic drugs such as clozapine; antiparkinsonian drugs such as pergolide and cabergoline; glucocorticoids; and antifungal drugs such as itraconazole and amphotericin B. NSAIDs, including selective cyclo-oxygenase (COX)-2 inhibitors, are included as a result of their ability to cause heart disease, particularly in patients with an already existing cardiorenal dysfunction. Two drug groups are of particular concern. Anthracyclines and their derivatives may cause cardiomyopathy in a disturbingly high number of exposed individuals, who may develop symptoms of insidious onset several years after drug therapy. The risk seems to encompass all exposed individuals, but data suggest that children are particularly vulnerable. Thus, a high degree of awareness towards this particular problem is warranted in cancer survivors subjected to anthracycline-based chemotherapy. A second group of problematic drugs are the NSAIDs, including the selective COX-2 inhibitors. These drugs may cause renal dysfunction and elevated blood pressure, which in turn may precipitate heart failure in vulnerable individuals. Although NSAID-related cardiotoxicity is relatively rare and most commonly seen in elderly individuals with concomitant disease, the widespread long-term use of these drugs in risk groups is potentially hazardous. Pending comprehensive safety analyses, the use of NSAIDs in high-risk patients should be discouraged. In addition, there is an urgent need to resolve the safety issues related to the use of COX-2 inhibitors. As numerous drugs from various drug classes may precipitate or worsen heart failure, a detailed history of drug exposure in patients with signs or symptoms of heart failure is mandatory.

Medical management of advanced Parkinson's disease

The management of advancing Parkinson's disease (PD) is a daunting task, complicated by dynamic medication responses, side effects, and treatment-refractory symptoms in an aging patient population. The motor and nonmotor complications of advancing PD are reviewed, and practical treatment strategies are provided. Careful assessment in the context of the known natural history of advancing PD and rational treatment choices can create significant improvement in the lives of patients who have advancing PD.

Advances in the treatment of prolactinomas

Prolactinomas account for approximately 40% of all pituitary adenomas and are an important cause of hypogonadism and infertility. The ultimate goal of therapy for prolactinomas is restoration or achievement of eugonadism through the normalization of hyperprolactinemia and control of tumor mass. Medical therapy with dopamine agonists is highly effective in the majority of cases and represents the mainstay of therapy. Recent data indicating successful withdrawal of these agents in a subset of patients challenge the previously held concept that medical therapy is a lifelong requirement. Complicated situations, such as those encountered in resistance to dopamine agonists, pregnancy, and giant or malignant prolactinomas, may require multimodal therapy involving surgery, radiotherapy, or both. Progress in elucidating the mechanisms underlying the pathogenesis of prolactinomas may enable future development of novel molecular therapies for treatment-resistant cases. This review provides a critical analysis of the efficacy and safety of the various modes of therapy available for the treatment of patients with prolactinomas with an emphasis on challenging situations, a discussion of the data regarding withdrawal of medical therapy, and a foreshadowing of novel approaches to therapy that may become available in the future.

Dopamine agonists in Parkinson’s disease

Levodopa (LD), the immediate precursor of dopamine, is the most effective agent in the treatment of Parkinson's disease (PD). While quite successful in treating the primary motor deficits of PD, most patients eventually develop LD-related motor fluctuation, dyskinesias and other adverse effects associated with chronic LD therapy. There is also concern that LD is neurotoxic, although this has not been demonstrated in any in vivo studies. Dopamine agonists (DAs) have been shown to be about as effective as LD in symptomatic treatment of mild-to-moderate PD. In addition, there is a lower tendency to develop motor fluctuations and dyskinesias with DA treatment than after initiation of therapy with LD. Furthermore, there is preclinical and clinical data to suggest a slowing of neurodegeneration with DAs. The adverse effects of DAs are similar to those experienced with LD, except that the ergot agents are associated with a small risk of tissue fibrosis not noted with the non-ergot DAs.

Constrictive pericarditis and pleuropulmonary fibrosis secondary to cabergoline treatment for Parkinson's disease

A 63 year old man with a six year history of Parkinson's disease presented with signs of right heart failure following a knee replacement. Constrictive pericarditis was diagnosed and a radical pericardectomy performed. Six months later, the patient remained unwell with raised inflammatory markers. An inflammatory fibrotic reaction caused by cabergoline was diagnosed. He improved after cessation of cabergoline.

Acute Onset of Severe Dilated Cardiomyopathy During Bromocriptine Therapy

OBJECTIVE:

To report a case of severe dilated cardiomyopathy (DCMP) in a patient on bromocriptine therapy for a microprolactinoma.

CASE SUMMARY:

A 31-year-old African American female, who had been receiving bromocriptine 5 mg orally daily for a microprolactinoma during the preceding month, developed severe DCMP. An echocardiogram showed a markedly dilated left ventricle with severe reduction in the left-ventricular ejection fraction in the absence of any other identifiable causes of DCMP such as a peripartum state, ethanol use, preceding systemic viral illness, chronic hypocalcemia, chronic hypophosphatemia, or chronic uncontrolled tachycardia. She improved substantially (both symptomatically and echocardiographically) after cessation of bromocriptine therapy and initiation of supportive treatment of congestive heart failure (CHF). She showed no recurrence of CHF at a follow-up visit 2 months after withdrawal of the supportive care. The patient was not rechallenged with bromocriptine due to the clinical/ethical gravity of this probable adverse effect.

DISCUSSION:

Although cardiopulmonary adverse effects have been reported with the use of cabergoline (another dopamine agonist), to the best of our knowledge, this is the first case report of severe life-threatening DCMP associated with bromocriptine therapy. Causality assessment using the Naranjo probability scale revealed that the adverse drug event was probable.

CONCLUSIONS:

Bromocriptine was probably associated with DCMP in a patient being treated for a microprolactinoma. Severe DCMP needs to be considered a potentially life-threatening but reversible adverse effect of bromocriptine therapy for microprolactinoma of the pituitary gland.

Severe multivalvular heart disease: A new complication of the ergot derivative dopamine agonists

We report on 4 new cases of valvular heart disease in Parkinson's disease patients treated with the ergot derivative dopamine agonists pergolide and cabergoline. Noninflammatory fibrotic degeneration of cardiac valves has been reported to occur in patients with carcinoid syndrome and to occasionally complicate therapies with the anti-migraine ergot alkaloid ergotamine and methysergide and with the appetite suppressants fenfluramine and dexfenfluramine. In these cases, the pathogenesis is suspected to involve serotonin-mediated abnormal fibrogenesis by means of the 5-HT2B receptors, which are expressed in the fibroblasts of heart valves. Based on strikingly similar echocardiographic and histopathological features, we strongly suspect that ergot-derived dopamine agonists may cause a valvular heart disease nearly identical to that seen in those conditions. These cases add to a rapidly growing and worrying list of similar published reports, suggesting that we may well be facing a novel, yet unrecognized, complication of this class of agents, which are widely used not only in Parkinson's disease but also in restless legs syndrome and various common endocrine dysfunctions. Therefore, until more is known about the true prevalence of this side effect, we propose that an assessment of cardiac function be performed before and in the course of a long-term therapy with ergot derivative dopamine agonists.

[Severe pleuropericarditis induced by long-term bromocriptin therapy, report of a case and review of the literature]

INTRODUCTION

Bromocriptin, member of the class of ergolines, is commonly prescribed as treatment of Parkinson's disease. Apart from vascular, digestif, neurologic and psychic disorders, the authors report cases of retroperitoneal fibrosis and pleural effusion, as adverse reactions related to the bromocriptin.

SYNTHESIS

About 40 cases of skin, pleural, lung and retroperitoneal attacks were described after long term and high doses of bromocriptin. More ten years ago, the first case of constrictive pericarditis was cited in the medical literature, and the bromocriptin was incriminated as responsible. Since then, two other cases were cited. Our observation is a constrictive pericarditis, found in a 72 years old patient treated with bromocriptin for Parkinson's disease since five years (cumulative dose intake 73 grams). Investigations aimed to establish etiology were negative. Bromocriptin is suspected and the treatment is discontinued. As in the three other cases, cardiac and neurologic conditions markedly improved after bromocriptin's withdrawal. A pericardic thickening persists at the echography.

CONCLUSION

The responsibility of bromocriptin in the etiology of constrictive pericarditis is seldom discussed, because it remains an exclusion diagnosis. Periodic chest X-ray and echocardiography should be considered in patients with long-term bromocriptin treatment.

Switching from ergot to nonergot dopamine agonists in Parkinson's disease: A clinical series and five-drug dose conversion table

Of 99 patients on ergot-derived dopamine agonists informed about possible long-term side effects, switching to a nonergot was undertaken in 88 (89%). There were adverse events in 26%. After 11 months, 82% were on their switch agonist and 93% were on any agonist. Switching dopamine agonists is feasible in this population.

Rationale for current therapies in Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder that affects an estimated 1 million people in the US and tens of millions worldwide. Medication therapy has made significant advances and improvements especially over the last 10 years. A number of new treatments and new strategies have emerged and the quality of life for the average sufferer has improved. This review will describe the rationale and strategies for current medical therapies in PD, with special emphasis on the use of antipsychotic agents. Levodopa remains the most efficacious medication for the management of PD. Long-term use of levodopa, however, is associated with the development of motor fluctuations including dyskinesia. Trials with dopamine agonists have demonstrated a delay in the onset of dyskinesia with the use of this therapy. There is also active, ongoing investigation to determine whether a neuroprotective effect may be present with agonist therapy. Anticholinergics have been successfully used to treat tremor as well as sialorrhoea and urinary urgency. Catechol-O-methyltransferase inhibitors increase 'on time', decrease 'off time,' and improve motor scores. Continuous stimulation of dopamine receptors may decrease the fluctations observed with pulsatile delivery of anti-Parkinsonian medications, but this will require more study. Monoamine oxidase-B inhibitors, specifically selegiline, may provide symptomatic improvement; the question as to whether a neuroprotective benefit is present remains unanswered. Amantadine has demonstrated both symptomatic benefit and dyskinesia benefit in some patients. Selective dopamine blockers such as clozaril and quetiapine, have been shown to be effective in the treatment of psychosis. This class of medications is particularly useful as an adjunctive to levodopa and dopamine agonists. Doses of dopaminergic drugs can be escalated to treat Parkinsonian symptoms, whereas selective dopamine blockers can be added to block psychosis. Old management strategies required a reduction in dopaminergic therapy and therefore worsened Parkinsonian symptoms. Even though there have been great advances in the medical options for symptomatic management of PD, there are still many unmet needs for this patient population.

Fibrotic valvular heart disease subsequent to bromocriptine treatment

Ergot alkaloids, such as ergotamine, have been associated with numerous vascular complications and with valvular heart disease. The authors describe a man who developed fibrosis of three heart valves during a 5-year treatment with bromocriptine for Parkinson disease. There were no other plausible causes. To our knowledge, such a side effect has never been described with this drug.

Emerging therapies in the pharmacological treatment of Parkinson's disease

The pharmacological management of Parkinson's disease is a complex and dynamic task; there is no one 'right' strategy indicating which drugs should be used at a particular stage of the disease. There are now many different drugs belonging to several classes that may be effective, and there are still differences of opinion among leading clinicians about the best course of treatment. This review focuses on drug therapy for the motor impairment in Parkinson's disease. Current and future research directions are summarised by taking inventory of recent and innovative areas of development in the field, representing each category with at least one of its featured treatments. The main research efforts are being directed towards delaying the use of levodopa or finding therapies to be used as adjunct to it, in order to postpone motor complications and, in particular, dyskinesias. One of the recent trends is early employment of dopamine agonists. Additional efforts are being directed towards protecting and restoring dopamine neurons. Novel therapies acting on non-dopaminergic systems are also being researched.

Dopamine receptor agonists for treating prolactinomas

Prolactinomas are the most common hormone-secreting pituitary tumours and cause infertility and gonadal and sexual dysfunction in both sexes. The approach to prolactinomas has changed in the last 25 years thanks to the availability of dopaminergic drugs characterised by a potent prolactin-inhibitory effect, a tumour shrinking effect associated with a satisfactory tolerability. In more recent years, cabergoline 1-[(6-allelylergolin-8beta-yl)carbonyl]-1-[3-(dimethylamino) propyl]-3-ethyl-urea an ergoline derivative with potent, selective and long-lasting inhibitory activity on prolactin release, has been used to suppress prolactin secretion in women with hyperprolactinaemia. Cabergoline was shown to be significantly more effective than bromocriptine in inducing a complete biochemical response and clinical efficacy and was better tolerated than bromocriptine in the majority of patients. Notable tumour shrinkage until tumour disappearance was observed during cabergoline treatment in most patients with macroprolactinoma and it was also proven effective in patients resistant to or with a poor response to bromocriptine. In view of the limited data on cabergoline-associated pregnancies and the long half-life of the drug, it is currently recommended that women hoping to become pregnant, once ovulatory cycles have been established, should discontinue cabergoline therapy 1 month before they intend to conceive. However, no data concerning negative effects on pregnancy or offspring have been reported. The great efficacy of this compound together with its excellent tolerability makes this drug the current treatment of choice for the majority of patients with hyperprolactinaemic disorders.

A review of pramipexole and its clinical utility in Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disorder characterised by selective loss of dopaminergic neurones in the substantia nigra and resulting in progressive disability. Therapy has focused on replacing depleted dopamine (DA) via supplementation with levodopa or DA agonists. Pramipexole (Mirapex), Pharmacia Corp.) has recently been approved for the treatment of PD. Evidence from preclinical studies and clinical trials have proven the effectiveness of this agent in ameliorating the symptoms of PD. There is also non-human evidence that pramipexole may be neuroprotective and could therefore possibly slow disease progression; however, this has yet to be proven in humans. The use of pramipexole may be limited by its side effect profile compared to standard therapies and its relatively higher cost compared to levodopa. Despite these concerns, pramipexole does have a role in the treatment of PD in all stages of the illness and may arguably be the treatment of choice in early disease. In addition to its use in PD, pramipexole has shown some utility in the treatment of restless legs syndrome (RLS), depression and schizophrenia.

Initial treatment of early Parkinson's disease: a review of recent, randomized controlled trials

Many studies have shown dopamine agonists to significantly improve parkinsonian symptoms compared with placebo in early Parkinson's disease (PD), but how do agonists compare with the standard treatment of levodopa? Recently, three large, multicenter, randomized controlled studies directly comparing a dopamine agonist with levodopa as initial therapy in early PD have been published. These studies suggest that although both agents effectively ameliorate parkinsonian symptoms, levodopa was superior to dopamine agonists as measured by improvement in Unified Parkinson's Disease Rating Scale (UPDRS) scores. However, levodopa was more frequently associated with dopaminergic motor complications, and the dopamine agonists were more commonly associated with adverse events. Until further studies clearly demonstrate the beneficial effects of one therapeutic strategy over another, the decision to initiate treatment in early PD with either an agonist or levodopa will be based on the favorable motor complication profile of agonists versus the more potent antiparkinsonian effects and the favorable side-effect profile of levodopa.

Cabergoline

Cabergoline (CAB) (1-[(6-allelylergolin-8 beta-yl)carbonyl]-1-[3-(dimethylamino)propyl]-3-ethyl-urea) is an ergoline derivative with potent, selective and long-lasting inhibitory activity on prolactin (PRL) secretion acting on dopamine receptors present in pituitary lactotrophes. Receptor binding studies have demonstrated that CAB has high in vitro selectivity and affinity for the subtype D2 of the dopamine receptor. In cultures of rat anterior pituitary cells, the concentrations of CAB and bromocriptine required to inhibit PRL secretory activity by 50% (IC50) were 0.1 and 3.4 nmol/l, respectively. As compared to bromocriptine, CAB was more potent in inhibiting the binding of [3H]N-n-propylnorapomorphine and it occupied the receptor for longer. These effects were observed in all areas of the rat brain. In vivo, CAB at doses of 0.125-1 mg twice weekly caused a dose-dependent suppression of PRL secretion in women with hyperprolactinaemia. CAB was shown to be significantly more effective than bromocriptine in inducing a complete biochemical response and clinical efficacy and was better tolerated than bromocriptine in the majority of patients. Notable tumour shrinkage until tumour disappearance was observed during CAB treatment in most patients with macroprolactinoma. CAB was also shown to be effective in patients resistant or poorly responsive to bromocriptine. In view of the limited data on CAB-associated pregnancies and the long half-life of the drug, it is currently recommended that women seeking to became pregnant, once ovulatory cycles have been established, should discontinue CAB therapy 1 month before they intend to conceive. However, no data on negative effects on pregnancy or offspring have been reported. The great efficacy of CAB together with its excellent tolerability makes this drug the current treatment of choice for the majority of patients with hyperprolactinaemic disorders. Very recently, the efficacy of CAB treatment has been reported in patients with acromegaly and clinically non-functioning adenomas with controversial results. CAB was also reported to have some efficacy in patients with Nelson's syndrome and Cushing's disease although these data are available only for limited case reports.

Medical treatment of later-stage motor problems of Parkinson disease

Parkinson disease progression is associated with the development of levodopa short-duration responses and dyskinesias, as well as gait freezing. Levodopa dose adjustment and adjunctive treatment with dopamine agonists form the major therapeutic strategies. Catechol O-methyltransferase inhibitors are also appropriate considerations, whereas other drugs, including selegiline, amantadine, anticholinergic agents, and propranolol, have a more minor role.