Prescribing Pattern for Parkinson's Disease in Indian Community before Referral to Tertiary Center

Levodopa Dose Equivalency in Parkinson's Disease: Updated Systematic Review and Proposals

BACKGROUND

To compare drug regimens across clinical trials in Parkinson's disease (PD) conversion formulae between antiparkinsonian drugs have been developed. These are reported in relation to levodopa as the benchmark drug in PD pharmacotherapy as 'levodopa equivalent dose' (LED). Currently, the LED conversion formulae proposed in 2010 by Tomlinson et al. based on a systematic review are predominantly used. However, new drugs with established and novel mechanisms of action and novel formulations of longstanding drugs have been developed since 2010. Therefore, consensus proposals for updated LED conversion formulae are needed.

OBJECTIVES

To update LED conversion formulae based on a systematic review.

METHODS

The MEDLINE, CENTRAL, and Embase databases were searched from January 2010 to July 2021. Additionally, in a standardized process according to the GRADE grid method, consensus proposals were issued for drugs with scarce data on levodopa dose equivalency.

RESULTS

The systematic database search yielded 3076 articles of which 682 were eligible for inclusion in the systematic review. Based on these data and the standardized consensus process, we present proposals for LED conversion formulae for a wide range of drugs that are currently available for the pharmacotherapy of PD or are expected to be introduced soon.

CONCLUSIONS

The LED conversion formulae issued in this Position Paper will serve as a research tool to compare the equivalence of antiparkinsonian medication across PD study cohorts and facilitate research on the clinical efficacy of pharmacological and surgical treatments as well as other non-pharmacological interventions in PD. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Practical pearls to improve the efficacy and tolerability of levodopa in Parkinson's disease

INTRODUCTION

Levodopa is the most effective medication for the treatment of motor symptoms of Parkinson's disease (PD). Several factors may affect the efficacy and tolerability of levodopa. These include the timing, dosage and administration of levodopa, concomitant drugs, food, PD-associated non motor symptoms, and various neurologic and non-neurologic comorbidities. If not appropriately addressed, these issues may limit levodopa efficacy, tolerability, and compliance.

AREAS COVERED

This article reviews the basics of the metabolism of orally administered levodopa, its side effects, and the factors that may affect its tolerability and efficacy. We provide several practical pearls to improve the tolerability and efficacy of levodopa.

EXPERT OPINION

Protein-rich food delays and reduces levodopa absorption. Hence, levodopa should preferably be administered in a relatively empty stomach. Carbidopa dosing is crucial as it not only enhances the entry of levodopa into the central nervous system, but also reduces levodopa's peripheral adverse effects. Patients experiencing the early side effects such as nausea/vomiting should be prescribed with anti-nausea medications that do not block dopamine receptors. Non-oral routes of administration can be used to obviate persistent gastrointestinal side effects. Implementation of these and other tips may help improve the tolerability and efficacy of levodopa.

Potentially inappropriate prescriptions of antipsychotic and anticholinergic drugs in patients with Parkinson's disease

Aim: The objective was to determine the prevalence of the potentially inappropriate antipsychotics and anticholinergics used in patients with Parkinson's disease. Materials & methods: A cross-sectional study identified the prescription of antipsychotics, anticholinergics and drugs for the treatment of Parkinson's disease. The anticholinergic burden was evaluated, and quetiapine and clozapine were considered to be adequate antipsychotics. Results: 2965 patients with Parkinson's disease were identified. The presence of psychiatric disorders and other neurological pathologies was associated with a greater probability of receiving potentially inappropriate antipsychotic prescriptions. The presence of greater number of comorbidities was associated with a greater probability of receiving anticholinergics. Conclusion: Older age and associated comorbidities, especially psychiatric and neurological comorbidities, increase the likelihood of patients with Parkinson's disease being prescribed antipsychotics and anticholinergics.

Comparison of effectiveness of trihexyphenidyl and levodopa on motor symptoms in Parkinson's disease

Despite anti-cholinergics being the oldest type of medication used for the treatment of Parkinson's disease (PD), the mechanism of action and exact benefit is unclear. This study compared the effectiveness of trihexyphenidyl (THP) and levodopa (LD) on motor symptoms in patients with PD. Patients with PD who are currently taking or had taken THP were recruited. UPDRS-III was done following overnight medication OFF state and 30 min, 60 min, 90 min, and 120 min after THP (4 mg). After a forty-eight-hour interval, UPDRS-III was assessed one hour after Levodopa/carbidopa (200/50 mg) in an overnight OFF state. Twenty patients with a mean age of 57.9 ± 7.8 years and mean duration of illness of 5.1 ± 3.6 years were recruited. UPDRS-III score reduction (%) with THP was maximum in the tremor sub-score (53.8 ± 22.8) and was significantly better compared to improvement in total-UPDRS-III (27.0 ± 14.7), bradykinesia-UPDRS-III (22.2 ± 27.2), rigidity-UPDRS-III (29.5 ± 28.0) and axial-UPDRS-III (8.1 ± 13.3) sub-score. In comparison, respective LD improvement was 67.1 ± 22.9 (tremor-UPDRS-III), 61.3 ± 14.4 (total-UPDRS-III), 67.9 ± 32.1 (bradykinesia-UPDRS-III), 65.3 ± 25.5 (rigidity-UPDRS-III) and 50.7 ± 16.0 (axial-UPDRS-III). Improvement (%) in tre-UPDRS-III post-THP was comparable to that of post-LD (53.8 ± 22.8 vs. 67.1 ± 22.9, p = 0.057). Those with same or better tremor response with THP had significantly milder baseline tremor severity than those who had better response with LD (tre-UPDRS-III-OFF, 10.0 ± 2.8 vs. 5.8 ± 4.0, p = 0.013). Both THP and LD showed significant improvement in UPDRS-III. With THP, the maximum degree of improvement was in the tremor sub-score and not significantly different to that obtained by LD. Those with better tremor response on THP had milder tremor severity.

Anticholinergics May Carry Significant Cognitive and Gait Burden in Parkinson's Disease

Background

Anticholinergic drugs are associated with significant cognitive and other adverse events in older adults, including those with Parkinson's disease (PD). Anticholinergic effects are considered lesser in younger individuals and the burden and outcomes in younger patients with PD are unknown.

Objectives

To determine the cumulative anticholinergic burden in a cohort of younger of patients with PD and to correlate the same with cognitive impairment and freezing of gait (FOG).

Methods

We conducted a cross-sectional study to identify the cumulative anticholinergic burden from medications prescribed to patients with PD. Two standard scales, the Anticholinergic Cognitive Burden (ACB) scale and the ACB score, were used to calculate the anticholinergic burden from prescriptions. We identified commonly prescribed drugs contributing to anticholinergic effects and correlated the cumulative ACB score with cognitive impairment (Movement Disorder Society-Unified Parkinson's Disease Rating Scale item 1.1) and FOG (Movement Disorder Society-Unified Parkinson's Disease Rating Scale items 2.13 and 3.11).

Results

We recruited 287 patients with PD (68.9% male) with a mean age of 56.9 ± 11.8 years and a duration of symptoms 6.3 ± 6.9 years. Median ACB score was 4 (range 0-12). A total of 164 (58.4%) patients had total ACB score > 3. ACB score > 3 was independently associated with cognitive impairment (Odds Ratio, 2.55; 95% confidence interval, 1.43-4.53; P < 0.001) and FOG using patient-reported measures (Odds Ratio, 3.192; 95% Confidence Interval, 1.68-6.07; P < 0.001) and objective measures (odds ratio, 2.41; 95% confidence interval, 1.27-4.6, P = 0.007).

Conclusion

Patients with PD are exposed to significant anticholinergic burden from drugs prescribed for PD and non-PD indications. Higher anticholinergic burden is associated with cognitive impairment and FOG even in younger patients with PD.

Evolution of Initial Pharmacologic Treatment of Newly Diagnosed Parkinson's Disease Patients over a Decade in Singapore

Objective

The aim of this study is to compare Parkinson's disease (PD) treatment practices by movement disorder (MD) specialists across a decade, and to determine the factors that influence drug choice for the motor symptoms of PD in newly diagnosed drug-naïve patients.

Methods

This prospective temporal analysis included patients seen at the National Neuroscience Institute in Singapore and diagnosed with PD by MD specialists in the years 2007 and 2017. Primary outcomes were use of specific PD drugs and changes in drug-prescribing patterns. Descriptive analyses and multivariable logistic regression models determined the extent to which patient characteristics were associated with type of PD treatment.

Results

Of 230 patients with PD (mean (SD) age, 66.7 (10.3) years), 131 (57.0%) were male. From 2007 to 2017, the use of ergot dopamine agonists and anticholinergics decreased from 19.3% to 2.0% (P < 0.001) and from 12.0% to 2.7% (P = 0.004), respectively. The use of monoamine oxidase B inhibitors (MAOBI) increased from 13.3% to 25.2% (P = 0.033). The use of levodopa (LD)-sparing strategies decreased nonsignificantly from 33.7% to 24.5% (P = 0.133). Overall, 196 (85.2%) patients were initiated on symptomatic monotherapy, with LD being the most commonly prescribed. MAOBI was the most common drug used in combination therapy. Age ≤70 (adjusted OR, 11.9; 95% CI, 4.5–31.5) and Hoehn and Yahr (HY) stage <2 (adjusted OR, 3.4; 95% CI, 1.5–7.7) were independent factors for LD-sparing strategies. Non-LD prescriptions (13 of 92; 14.1%) were more likely to be discontinued compared to LD ones (6 of 149; 4.0%) (P = 0.005).

Conclusions

Drug-prescribing patterns in PD have changed significantly through the last decade, influenced by emerging evidence and reports of adverse drug effects. Choosing drugs based on the patient's age and disease severity remain sound guiding principles across the years. It is important that international and national guidelines for pharmacotherapy in PD be updated consistently throughout different socioeconomic settings to optimize care.

Patterns and Determinants of Prescribing for Parkinson's Disease: A Systematic Literature Review

Since the discovery of levodopa (L-dopa) in 1967, the range of medications available to treat Parkinson's disease has increased significantly and guidance on the use, efficacy, and safety of these medications has evolved. To assess levels of adherence to national prescribing guidelines and awareness of changes in the efficacy and safety data published in the profiles of medications for the treatment of PD, we have reviewed studies on patterns and determinants of prescribing PD medications conducted in the last 50 years (since the discovery of L-dopa). A systematic literature review was conducted using EMBASE (1967 to March, 2018), Ovid MEDLINE(R) ALL (1967 to March 16, 2018), PsycINFO (1967 to the 2nd week of March, 2018), and PubMed to identify all studies measuring prescribing patterns of PD medication between 1967 and 2017. Study design, source of data, country, year of study, number of patients and/or prescriptions, unit of analysis, prescribing determinants, and percentage utilisation of PD medications were extracted where possible. 44 studies examining prescribing patterns and/or prescribing determinants across 17 countries were identified. Unsurprisingly, L-dopa was the most commonly prescribed medication in all studies, accounting for 46.50% to 100% of all prescriptions for PD. In several studies, the prescribing rate of ergot-derived dopamine agonists (DAs) decreased over time in concordance with guidance. In contrast, the prescribing rates of non-ergot DAs increased over the last ten years in most of the included studies. In examining prescribing factors, two major categories were exemplified, patients' factors and prescribers' factors, with patients' age being the most common factor that affected the prescription in most studies. In conclusion, L-dopa is now the most commonly prescribed medication for cases of PD but there is large variation in the prescribing rates of catechol-O-methyltransferase (COMT) inhibitors, monoamine oxidase B (MAO-B) inhibitors, amantadine, and anticholinergics between countries. New studies examining the effects of recent clinical trials and measuring the prescribing rates of newly approved medications are warranted.