Treatment of Parkinson's disease with ropinirole after pergolide-induced retroperitoneal fibrosis

Parkinson's disease between internal medicine and neurology

General medical problems and complications have a major impact on the quality of life in all stages of Parkinson's disease. To introduce an effective treatment, a comprehensive analysis of the various clinical symptoms must be undertaken. One must distinguish between (1) diseases which arise independently of Parkinson's disease, and (2) diseases which are a direct or indirect consequence of Parkinson's disease. Medical comorbidity may induce additional limitations to physical strength and coping strategies, and may thus restrict the efficacy of the physical therapy which is essential for treating hypokinetic-rigid symptoms. In selecting the appropriate medication for the treatment of any additional medical symptoms, which may arise, its limitations, contraindications and interactions with dopaminergic substances have to be taken into consideration. General medical symptoms and organ manifestations may also arise as a direct consequence of the autonomic dysfunction associated with Parkinson's disease. As the disease progresses, additional non-parkinsonian symptoms can be of concern. Furthermore, the side effects of Parkinson medications may necessitate the involvement of other medical specialists. In this review, we will discuss the various general medical aspects of Parkinson's 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.

Ropinirole therapy for Parkinson's disease

Ropinirole (Requip, GlaxoSmithKline) is a novel nonergoline dopamine D2 agonist indicated for the treatment of early and advanced Parkinson's disease. It is mainly metabolized by the liver and its elimination half-life is approximately 5.8 h. When used as monotherapy in early Parkinson's disease, ropinirole improves signs and symptoms of the disorder. When used as an adjunct to levodopa in advanced Parkinson's disease patients with motor fluctuations, ropinirole reduces off time and allows a reduction of levodopa dose. The initial use of ropinirole in early Parkinson's disease to which levodopa is added when necessary, has been demonstrated to lead to a lower incidence of dyskinesias compared with treatment with levodopa alone. An 18F-dihydroxyphenylalanine positron emission tomography study suggested the possibility that ropinirole could slow the progression of loss of dopamine neurons compared with treatment with levodopa but this remains to be proven. Side effects of ropinirole include nausea, somnolence, edema, orthostatic hypotension, hallucinations and dyskinesia. A once-daily formulation of ropinirole is currently in development that has the potential for greater convenience, improved tolerability and greater efficacy.

Ropinirole, a non-ergoline dopamine agonist

Dopamine agonists have become indispensable in the treatment of Parkinson's disease. In every-day practice, however, the decision to select the best compound for an individual patient is rendered difficult because of the large number of substances available on the market. This review article provides a closer look at the experimental and clinical studies with ropinirole published so far. Ropinirole is a non-ergoline dopamine agonist which has been proven to be effective in both, monotherapy and combination therapy of idiopathic Parkinson's disease. In addition to ameliorating bradykinesia, rigor, and tremor, ropinirole facilitates the daily life and improves depressive moods of patients with Parkinson's disease. The long-term complications of levodopa are avoided, and problems commonly associated with levodopa treatment are reduced. Ropinirole appears to have a neuroprotective effect. In addition to Parkinson's disease, ropinirole has also been used successfully in the treatment of restless legs syndrome.

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.

Rapid onset of pergolide-induced pulmonary fibrosis in a patient with corticobasal degeneration

A 66-year-old man presented with gradually increasing dyspnoea and reduced exercise tolerance. There was no chest pain or any other respiratory symptoms, he had never smoked and there was no occupational exposure to dusts, toxins or asbestos. He also complained of a dull pain and numbness in his left forearm, unrelated to exertion.

Previous medical history included ischaemic heart disease and parkinsonism which was unresponsive to escalating therapy. Medication on presentation included aspirin 75 mg, pergolide 1 mg three times daily and two Sinemet plus three times daily.

He was apyrexial and tachypnoeic (respiratory rate 32/min), oxygen saturation 89% on air, the peak expiratory flow rate was 140 litre/min, heart rate 82 beats/minute and bloot pressure 143/66 mmHg. The jugular venous pressure was not raised and there was poor lung expansion with florid, bibasal, late inspiratory crackles to the midzones. He was bradykinetic with a marked coarse, jerky resting tremor in the left upper limb with quasi-purposeful involuntary movements and marked apraxia. There was greatly increased axial tone. No limb weakness was demonstrated, reflexes were unremarkable and the plantar response was flexor. There was sensory impairment in the left arm and leg to all modalities. His gait was bradykinetic and shuffling with retropulsion on stopping. He had a full range of eye movements with unrestricted vertical gaze.

Full blood count, urea and electrolytes, liver function tests, calcium and creatine kinase were all normal. His C-reactive protein level was 63 mg/litre and erythrocyte sedimentation rate was 45mm/hr. Arterial blood gas analysis on air revealed; partial pressure of arterial oxygen (PaO2) 7.2 Kpa, partial pressure of arterial carbon dioxide (PaCO2) 2.6 Kpa, pH 7.52, base excess 2, bicarbonate 26 mmol. An electrocardiogram showed sinus rhythm with Q waves in III and aVf.

Chest X-ray showed bilateral extensive subpleural interstitial changes and honeycombing with loss of volume particularly in the right lung (Figure 1). High resolution computed tomography of the thorax demonstrated widespread bilateral reticular shadowing suggestive of fibrosis, honeycomb changes and associated basilar traction bronchiectasis. Lung function tests demonstrated a forced expiratory volume in 1 second (FEV1) 1.41 litres (52% of predicted), forced vital capacity (FVC) 1.45 litres (43% of predicted), FEV1/FVC 97% and gas transfer factor (DLCO) 17.4 (70% of predicted).

He was treated with oxygen and antibiotics. Transbronchial biopsy with histology demonstrated diffuse fibrous tissue, with no evidence of infection, tuberculosis or malignancy. Bronchoalveolar lavage revealed a neutrophilia. Microbiology cultures were negative. His antinuclear antibody, complement levels, classical antineutrophil cytoplasmic antibody, rheumatoid factors, Scl-70 and Jo-1 antibodies were normal. Reviewing his medication with pharmacy led to the discontinuation of pergolide since it has been reported to cause diffuse interstitial pulmonary fibrosis. A consultant neurological review was sought and a diagnosis of corticobasal degeneration made.

He was discharged on home oxygen. After 1 month of discontinuing pergolide, the patient subjectively noticed improvement in his dyspnoea, reflected in an increase in DLCO (82% predicted).

Diagnosis and management of pergolide-induced fibrosis

We report on 2 patients treated with pergolide, 1 of whom developed pleural fibrosis and the other retroperitoneal fibrosis. In both cases, an extensive diagnostic evaluation and surgical intervention were required to reach a diagnosis. Based on our experience with these patients and a review of cases of pergolide-induced fibrosis in the English-language literature, we propose guidelines for the diagnosis and management of this rare complication.

Frontiers in Neuropharmacotherapy Part II: Multiple Sclerosis and Parkinson’s Disease

Disease-modifying agents such as β-interferons and glatiramer acetate have a significant impact on slowing the course of relapsing-remitting multiple sclerosis (MS). Therapeutic guidelines recommend initiating therapy with 1 of the 3 agents shortly after diagnosis of clinically definite MS, but there is insufficient data to specifically select one of the therapies. New research helps differentiate the therapies based on their induction of neutralizing antibodies, optimal dosing, and monitoring strategies. New treatments for secondary progressive MS are also emerging with evidence for the use of interferon β-1b and the approval of mitoxantrone. Future therapies for MS include oral glatiramer acetate and combination therapy.

Levodopa continues to be the standard of care for the treatment of Parkinson’s disease, but the approval of newer therapies that spare the use of levodopa and improve safety profiles are changing the management of the disease. Dopamine agonists such as bromocriptine and pergolide have been used to manage complications of levodopa therapy in patients with advanced disease, but new research supports the use of the more selective dopamine agonists, pramipexole and ropinirole, as monotherapy in early Parkinson’s disease. The combination of a catechol-O-methyltransferase (COMT) inhibitor with levodopa provides a new therapeutic option for treating patients with motor complications in advanced disease.

Choosing the right dopamine agonist for patients with Parkinson's disease

Dopamine receptor agonists (DA) are assuming an increasing importance in the treatment of both early and advanced symptoms of Parkinson's disease (PD). However, choosing the right DA for patients with PD unfortunately remains more a pragmatic medical art than a science. The aim of this review is to provide a realistic point of view on the strengths and weaknesses of five DAs: bromocriptine, ropinirole, pergolide, pramipexole and piribedil. This has been done by analysing their respective: (1) flexibility in PD, i.e. in monotherapy, in early and in late combination with levodopa; (2) safety profile and (3) titration schedule. These five DAs are not evenly matched regarding these three criteria. The differences observed highlight the therapeutic value of piribedil, which has a flexible indication, adapted to all stages of PD, a safer profile and the most simple initiation schedule.

Pergolide in the treatment of patients with early and advanced Parkinson's disease

Introduced on the market in 1989, pergolide, a D1/D2 dopamine receptor agonist, is still widely prescribed for the treatment of patients with early and advanced Parkinson's disease (PD). Initially, pergolide was introduced as an adjunct therapy to levodopa treatment in patients exhibiting fluctuating motor responses and dyskinesias. Results of recent randomized controlled clinical trials in de novo patients with PD show that pergolide is able to improve parkinsonian symptoms when used as monotherapy. Moreover, preliminary results of a long-term monotherapy study in early PD suggest that pergolide is as effective as levodopa, and that a significant delay in the time of the onset of levodopa-induced motor complications can be obtained. A number of randomized studies have shown that pergolide is more effective than bromocriptine as adjunct therapy to levodopa in patients with advanced PD; the greater benefit found with pergolide could be ascribed to its action on both D1 and D2 dopamine receptors. However, controlled comparative studies with new dopamine agonists, such as ropinirole, cabergoline, and pramipexole, have not been performed yet. Interestingly, few open studies in patients with complicated PD have shown that high doses of pergolide (> 6 mg/d) are able to improve motor fluctuations and dyskinesias through a dramatic reduction of levodopa dosage. The side-effect profile of pergolide is similar to that of other dopamine agonists, and complications such as sleep attack and serosal fibrosis have been rarely reported.

Choosing dopamine agonists in Parkinson's disease

Dopamine agonists (DAs) have been shown to be effective as monotherapy in early stages of Parkinson's disease (PD) and as an adjunctive treatment to levodopa in advanced PD. Since bromocriptine, an ergot compound, was introduced as the first commercially available DA more than 25 years ago, additional DAs have become available for clinical use. There is a remarkable paucity of data, however, that would guide clinicians in their decision process to select the most appropriate DAs. We discuss the theoretical basis for comparing the various DAs, and provide a concise analysis and summary of comparative trials of DAs in PD.