Efficacy and tolerability of pramipexole for the treatment of primary restless leg syndrome: a meta-analysis of randomized placebo-controlled trials

Sleep Disturbance, Sleep Disorders and Co-Morbidities in the Care of the Older Person

Sleep complaints can be both common and complex in the older patient. Their consideration is an important aspect of holistic care, and may have an impact on quality of life, mortality, falls and disease risk. Sleep assessment should form part of the comprehensive geriatric assessment. If sleep disturbance is brought to light, consideration of sleep disorders, co-morbidity and medication management should form part of a multifaceted approach. Appreciation of the bi-directional relationship and complex interplay between co-morbidity and sleep in older patients is an important element of patient care. This article provides a brief overview of sleep disturbance and sleep disorders in older patients, in addition to their association with specific co-morbidities including depression, heart failure, respiratory disorders, gastro-oesophageal reflux disease, nocturia, pain, Parkinson's disease, dementia, polypharmacy and falls. A potential systematic multidomain approach to assessment and management is outlined, with an emphasis on non-pharmacological treatment where possible.

Quantitative Comparison of the Efficacies of 5 First-Line Drugs for Primary Restless Leg Syndrome

Comparative analyses of the efficacies of dopaminergic agonists (pramipexole, ropinirole, and rotigotine patch) and α-2-δ ligands (gabapentin enacarbil and pregabalin) for treatment of primary restless leg syndrome (RLS) are lacking because of the few head-to-head clinical trials. A model-based meta-analysis approach was employed to quantitatively compare the efficacies of these 5 first-line RLS drugs. Longitudinal efficacy data of RLS drugs were collected from published eligible literature. Mean changes in both the International Restless Leg Syndrome Study Group (IRLS) rating scale and Clinical Global Impression Improvement (CGI-I) scale response rate were analyzed. A study-level population pharmacodynamic model was used to fit the dose-effect relationship and to describe the therapeutic effect over time for RLS drugs and placebo, and the typical efficacies of these drugs were compared. The onset of action was rapid for RLS drugs. In the placebo group, typical maximum IRLS reduction (E_max,IRLS ) and CGI-I response rate (E_max,CGI-I ) were -9.34 points and 48.2%, respectively. After deducting placebo effects, we found that the baseline IRLS score was significantly correlated with the E_max,IRLS of dopaminergic agonists. Typical E_max,IRLS of dopaminergic agonists was expressed as - 7.7 - 0.682 × ( baseline IRLS score - 24 ) points. Typical E_max,IRLS values of pregabalin and gabapentin enacarbil were -5.95 points and -4.00 points, respectively. The therapeutic effect of dopaminergic agonists was found to be associated with baseline symptom severity. In RLS patients with more severe symptoms, the therapeutic effect of dopaminergic agonists tended to be better than that of α-2-δ ligands.

Pramipexole Overdose Associated with Visual Hallucinations, Agitation and Myoclonus

INTRODUCTION

Pramipexole is a dopamine D₂ receptor agonist used to treat idiopathic Parkinson's disease and primary restless legs syndrome. There is limited information on pramipexole overdose.

CASE REPORT

A 59-year-old male ingested 3 mg pramipexole, 2250 mg venlafaxine, 360 mg mirtazapine, with suicidal intent. He presented alert, had normal vital observations and normal pupillary reflexes. He was mildly agitated, reported visual hallucinations and was given 5 mg diazepam. He had a mildly elevated lactate of 1.7 mmol/L, but otherwise normal laboratory investigations. Overnight, he remained agitated with visual hallucinations and developed myoclonus while awake. He had increasing difficulty passing urine on a background of mild chronic urinary retention. On review, 14 h post-ingestion, he was hypervigilant, jittery and mildly agitated. He had pressured speech and difficulty focusing on questioning. He had a heart rate of 110 bpm, but had an otherwise normal examination, with no clonus or extrapyramidal effects. He was unable to mobilize due to dizziness and ataxia. Over the next few hours, he improved, the visual hallucinations and agitation resolved and he mobilized independently. Pramipexole was measured with liquid chromatography mass spectrometry. The initial plasma pramipexole concentration was 34.2 ng/mL (therapeutic range 0.2 to 7 ng/mL), 9 h post-overdose. Concentration time data fitted a one-compartment model with an estimated elimination half-life of 18 h.

DISCUSSION

Pramipexole overdose with hallucination, agitation, and myoclonus is consistent with adverse effects reported with therapeutic toxicity, but mirtazapine and venlafaxine may have contributed. Pramipexole concentrations exceeded the therapeutic range for over 24 h. With the increasing use of pramipexole in restless legs syndrome, adult overdoses may become more common.

Efficacy of Pramipexole for the Treatment of Primary Restless Leg Syndrome: A Systematic Review and Meta-analysis of Randomized Clinical Trials

PURPOSE

The objective of this meta-analysis was to systematically evaluate the efficacy of pramipexole for the treatment of primary moderate-to-severe restless leg syndrome (RLS).

METHODS

Databases of PubMed, OVID, ScienceDirect, SpringerLink, Thomson Reuters Web of Science, the Cochrane Library, the Wiley Online Library, ArticleFirst, CALIS, Study, CNKI, and WanFang were searched to identify randomized controlled trials (RCTs) investigating pramipexole for the treatment of primary moderate-to-severe RLS. A meta-analysis was then conducted to pool results.

FINDINGS

Twelve RCTs involving 3286 participants were included in this study. The mean (SD) treatment duration was 11.12 (5.72) weeks/person. The meta-analysis found that the post-treatment change in the International Restless Leg Syndrome Study Group Rating Scale (IRLS) score of the pramipexole group was significantly superior to that of the placebo group (weighted mean difference [WMD] = -4.64; 95% CI, -5.95 to -3.33; n = 8). More patients in the pramipexole group reported at least a 50% reduction in the IRLS score after treatment (risk ratio [RR] = 1.57; 95% CI, 1.43 to 1.73; n = 8). In terms of the scores for the Clinical Global Impression of Improvement scale (RR = 1.48; 95% CI, 1.31 to 1.66; n = 11) and the Patient Global Impression scale (RR = 1.54; 95% CI, 1.31 to 1.81; n = 9), treatment outcomes of the pramipexole group were significantly superior to those of the placebo group. In terms of the change in quality of life (WMD = 5.39; 95% CI, 2.28 to 8.50; n = 4), the change in daytime tiredness (WMD = -0.61; 95% CI, -1.21 to -0.01; n = 4), the change in the number of periodic limb movements per hour of sleep (WMD = -35.95; 95% CI, -56.42 to -15.48; n = 3), and the change in the quality of sleep (WMD = 3.60; 95% CI, 1.69 to 5.50; n = 6), the treatment outcomes of the pramipexole group were significantly superior to those of the placebo group.

IMPLICATIONS

This meta-analysis study indicated that pramipexole could effectively improve the symptoms of patients with primary moderate-to-severe RLS, although the quality of evidence was relatively low. Future clinical trials focusing on the medium-term and long-term treatment outcomes and using mainly objective indicators for evaluation are warranted. It is also necessary to pay close attention to augmentation during medication.

In the Clinic. Restless Legs Syndrome

This issue provides a clinical overview of restless legs syndrome, focusing on diagnosis, treatment, and practice improvement. The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP), including MKSAP (Medical Knowledge and Self-Assessment Program). Annals of Internal Medicine editors develop In the Clinic in collaboration with the ACP's Medical Education and Publishing divisions and with the assistance of additional science writers and physician writers.

Treatment response to sleep, pain, and mood disturbance and their correlation with sleep disturbance in adult patients with moderate-to-severe primary restless legs syndrome: Pooled analyses from 3 trials of gabapentin enacarbil

INTRODUCTION

This pooled analysis investigated the effects of gabapentin enacarbil (GEn) on clinical correlates of sleep disturbance in adults with moderate-to-severe primary restless legs syndrome (RLS) and no-to-moderate or severe-to-very severe baseline sleep disturbance.

METHODS

Co-primary end-points were mean change from baseline to week 12 in International Restless Legs Scale (IRLS) total score and proportion of responders ('much'/'very much' improved) on the investigator-rated Clinical Global Impression-Improvement (CGI-I) scale (week 12). Pain, mood, individual IRLS items, and safety were assessed.

RESULTS

The modified intent-to-treat population was 671 adults randomized to GEn 600 mg (n = 161), GEn 1200 mg (n = 266), or placebo (n = 244). GEn significantly improved least squares mean change in IRLS total score from baseline versus placebo for no-to-moderate (GEn 600 mg,- 12.3; 1200 mg, - 11.3; placebo, - 7.7) and severe-to-very severe (- 16.6; - 17.0; - 12.7) groups (all P < 0.01). Significantly more GEn-treated patients (both doses) were CGI-I responders (week 12) versus placebo in both sleep subgroups (all P < 0.01). GEn substantially improved mood and pain scores for both sleep subgroups versus placebo. The most frequent treatment-emergent adverse events were somnolence and dizziness.

CONCLUSION

GEn (600 mg and 1200 mg) was effective and well tolerated in adults with moderate-to-severe primary RLS regardless of baseline sleep disturbance level.