Naftidrofuryl

Nootropics as Cognitive Enhancers: Types, Dosage and Side Effects of Smart Drugs

Nootropics, also known as "smart drugs" are a diverse group of medicinal substances whose action improves human thinking, learning, and memory, especially in cases where these functions are impaired. This review provides an up-to-date overview of the potential effectiveness and importance of nootropics. Based on their nature and their effects, this heterogeneous group of drugs has been divided into four subgroups: classical nootropic compounds, substances increasing brain metabolism, cholinergic, and plants and their extracts with nootropic effects. Each subgroup of nootropics contains several main representatives, and for each one, its uses, indications, experimental treatments, dosage, and possible side effects and contraindications are discussed. For the nootropic plant extracts, there is also a brief description of each plant representative, its occurrence, history, and chemical composition of the medicinal part. Lastly, specific recommendations regarding the use of nootropics by both ill and healthy individuals are summarized.

Solubility, Permeability, and Dissolution Rate of Naftidrofuryl Oxalate Based on BCS Criteria

The Biopharmaceutics Classification System (BCS) was conceived to classify drug substances by their in vitro aqueous solubility and permeability properties. The essential activity of naftidrofuryl oxalate (NF) has been described as the inhibition of the serotonin receptors (5-HT₂), resulting in vasodilation and decreasing blood pressure. Since the early 1980s, NF has been used to treat several venous and cerebral diseases. There is no data available on the BCS classification of NF. However, based on its physical-chemical properties, NF might be considered to belong to the 1st or the 3rd BCS class. The present study aimed to provide data concerning the solubility and permeability of NF through Caco-2 monolayers and propose its preliminary classification into BCS. We showed that NF is a highly soluble and permeable drug substance; thus, it might be suggested to belong to BCS class I. Additionally, a high dissolution rate of the encapsulated NF based on Praxilene^® 100 mg formulation was revealed. Hence, it might be considered as an immediate-release (IR).

[Naftidrofuryl in arterial obstructive disease: A systematic revue of the literature]

INTRODUCTION

Arterial obstructive disease is a disease affecting 11 % of the general population. This prevalence is constantly increasing. Nafronyl is still prescribed despite a decreasing reimbursement rate since 2005. The objective of this study was to summarize data from the scientific literature on the efficacy and safety of nafronyl used for the treatment of peripheral arterial obstructive disease.

METHOD

A systematic review was made on EMBASE, MEDLINE and the Cochrane Library. Randomized controlled trials, systematic reviews and meta-analyses comparing naftidrofuryl with placebo were included. The main outcome was an improvement in the maximum walking distance or pain free walking distance. The quality of the reviews was analysed using a standardised reading grid. Only the best study was retained.

RESULTS

Among 193articles, one meta-analyses were selected. Naftidrofuryl improved the initial pain free walking distance by 60 % at six months, without a demonstrated increase in the risk of adverse reactions.

CONCLUSION

The efficacy of naftidrofuryl over the maximum walking distance in peripheral arterial obstructive disease appears similar to physical exercise or simvastatin.

Medical Therapy in Peripheral Artery Disease and Critical Limb Ischemia

OPINION STATEMENT

Peripheral artery disease (PAD) comprises atherosclerosis of the aorta and lower extremities. Many patients with PAD are asymptomatic, while others present with intermittent claudication (IC) or critical limb ischemia (CLI). Defined as rest pain or tissue loss that persists for >2 weeks, CLI represents the most severe clinical manifestation of PAD and is associated with an increased risk of limb loss and death. Patients with PAD, including those with CLI, are underdiagnosed and undertreated. In addition to smoking cessation, medical therapy with an antiplatelet agent and statin is recommended for all patients with PAD. Regular exercise has been shown to improve walking distance and quality of life in patients with symptomatic PAD and should be incorporated into each patient's treatment plan. In patients who have CLI and in those with persistent lifestyle-limiting claudication despite optimal medical therapy and an exercise program, revascularization is indicated for limb salvage and symptom relief, respectively. Consensus guidelines currently support an endovascular first approach to revascularization in the majority of cases. Surgical procedures provide an alternative to endovascular therapy in select cases.

Naftidrofuryl for intermittent claudication

BACKGROUND

Lifestyle changes and cardiovascular prevention measures are a primary treatment for intermittent claudication (IC). Symptomatic treatment with vasoactive agents (Anatomic Therapeutic Chemical Classification (ATC) for medicines from the World Health Organisation class CO4A) is controversial.

OBJECTIVES

To evaluate evidence on the efficacy and safety of oral naftidrofuryl (ATC CO4 21) versus placebo on the pain-free walking distance (PFWD) of people with IC by using a meta-analysis based on individual patient data (IPD).

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched October 2012) and CENTRAL (2012, Issue 9).For the original review the authors handsearched the European Journal of Vascular and Endovascular Surgery (1984 to 1994) and checked relevant bibliographies. They contacted the registration holder of naftidrofuryl and the authors of identified trials for any unpublished data.

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) with low or moderate risk of bias for which the IPD were available.

DATA COLLECTION AND ANALYSIS

We collected data from the electronic data file or from the case report form and checked the data by a statistical quality control procedure. All randomized patients were analyzed following the intention-to-treat (ITT) principle. The geometric mean of the relative improvement in PFWD was calculated for both treatment groups in all identified studies.The effect of the drug was assessed compared with placebo on final walking distance (WDf) using multilevel and random-effect models and adjusting for baseline walking distance (WD0). For the responder analysis, therapeutic success was defined as an improvement of walking distance of at least 50%.

MAIN RESULTS

We included seven studies in the IPD (n = 1266 patients). One of these studies (n = 183) was only used in the sensitivity analysis so that the main analysis included 1083 patients. The ratio of the relative improvement in PFWD (naftidrofuryl compared with placebo) was 1.37 (95% confidence interval (CI) 1.27 to 1.49, P < 0.001). The absolute difference in responder rate, or proportion successfully treated, was 22.3% (95% CI 17.1% to 27.6%). The calculated number needed to treat was 4.5 (95% CI 3.6 to 5.8).

AUTHORS' CONCLUSIONS

Oral naftidrofuryl has a statistically significant and clinically meaningful, although moderate, effect of improving walking distance in the six months after initiation of therapy for people with intermittent claudication. Access by researchers to data from RCTs that are suitable for IPD analysis should be possible through repositories of data from pharmacological trials. Regular formal appraisal of the balance of risk and benefit is needed for older pharmaceutical products.

Practical access to four stereoisomers of naftidrofuryl and their binding affinity towards 5-hydroxytryptamine 2A receptor

Naftidrofuryl oxalate (Praxilene®, 1) has been used for the treatment of intermittent claudication for more than 30 years. It selectively blocks vascular and platelet 5-hydroxytryptamine 2 (5-HT(2)) receptors. This drug is marketed as a mixture of four stereoisomers, and so far there is no individual biological evaluation on the single isomers. The purpose of this study is to provide an improved method for the preparation of all four stereoisomers of naftidrofuryl, and more importantly, to distinguish them in terms of their binding affinity to 5-hydroxytryptamine 2A (5-HT(2A)) receptor. The bioassay results revealed that the C-2S configuration of naftidrofuryl was crucial for the binding affinity with 5-HT(2A) receptor, and the C-2' configuration was less important for binding. In conclusion, our study may pave the way to develop single naftidrofuryl isomers with C-2S configuration as inhibitors of 5-HT(2A) receptor that have clinical significance as vasodilators and CNS agents.

Drug therapy for improving walking distance in intermittent claudication: a systematic review and meta-analysis of robust randomised controlled studies

OBJECTIVES

To evaluate the efficacy of pharmacological interventions in improving walking capacity and health-related quality of life for people with intermittent claudication. DATASOURCES: We searched Medline, EMBASE, Cochrane library and relevant websites for studies published from the start of the databases to February 2009. In addition, reference lists were manually searched.

REVIEW METHODS

Based upon a power calculation, only robust (n>56), peer-reviewed, double-blinded, randomised and placebo-controlled trials were included. The main outcomes evaluated were maximal walking distance (MWD) and pain-free walking distance on a treadmill. Random models were used in the statistical analysis, and chi-square test were used to test for heterogeneity.

RESULTS

Among 220 trials, only 43 trials fulfilled the quality criteria. Treatment periods, follow-up and treadmill protocols varied substantially. Vasodilator agents and phosphodiesterase inhibitors show robust significant results compared to placebo, but the improvements in MWD are modest. The highest benefit was caused by lipid-lowering agents, which in mean gained above 160 m in MWD, while the other agents only improved MWD about 50 m.

CONCLUSION

Several drugs have shown to improve MWD, but with limited benefits. Statins seem to be the most efficient drug at the moment.

Naftidrofuryl for intermittent claudication: meta-analysis based on individual patient data

OBJECTIVE

To assess the efficacy of naftidrofuryl compared with placebo in treating the symptoms of intermittent claudication.

DESIGN

Meta-analysis based on individual patient data.

DATA SOURCES

Medline, International Pharmaceutical Abstracts, Embase, Science Citation Index, and the Cochrane trial registers. Reference lists of retrieved articles were checked. Authors and companies were approached for additional information and individual patient data.

INCLUSION CRITERIA

Double blind, randomised controlled trials in patients with intermittent claudication receiving oral naftidrofuryl or placebo and with pain-free walking distance as primary outcome.

DATA COLLECTION

Individual patient data were collected from electronic data or from case report forms and checked for integrity.

ANALYSIS

All randomised patients were analysed following the intention to treat principle. Efficacy was assessed by the ratio of geometric mean of the relative improvement in pain-free walking distance after use of naftidrofuryl compared with placebo. In the analysis of responders, therapeutic success was defined as an improvement of walking distance at baseline by at least 50%.

RESULTS

In total, 1266 patients were randomised (1083 in the main analysis). The ratio of relative improvement in pain-free walking distance after use of naftidrofuryl compared with placebo was 1.37 (95% confidence interval 1.27 to 1.49). The difference in response rate was 22.3% (95% confidence interval 17.1% to 27.6%) and the number needed to treat for relief of symptoms during six months of treatment was 4.48 (95% confidence interval 3.62 to 5.85).

CONCLUSION

This meta-analysis of individual patient data provides evidence that naftidrofuryl has a clinically meaningful effect compared with placebo in improving walking distance in patients with intermittent claudication.

Naftidrofuryl for intermittent claudication

BACKGROUND

Lifestyle changes and cardiovascular prevention measures are a primary treatment for intermittent claudication (IC). Symptomatic treatment with vasoactive agents (Anatomic Therapeutic Chemical Classification (ATC) for medicines from the World Health Organisation class CO4A) is controversial.

OBJECTIVES

To evaluate evidence on the efficacy and safety of oral naftidrofuryl (ATC CO4 21) versus placebo on the pain-free walking distance (PFWD) of people with IC by using a meta-analysis based on individual patient data (IPD).

SEARCH STRATEGY

The Cochrane Peripheral Vascular Diseases Group searched their Trials Register (last searched December 2007) and CENTRAL (last searched 2007, Issue 4). We searched MEDLINE, EMBASE, International Pharmaceutical Abstracts, the Science Citation Index and contacted the authors and checked the reference lists of retrieved articles. We asked the manufacturing company for IPD.

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) with low or moderate risk of bias for which the IPD were available.

DATA COLLECTION AND ANALYSIS

We collected data from the electronic data file or from the case report form and checked the data by a statistical quality control procedure. All randomized patients were analyzed following the intention-to-treat (ITT) principle. The geometric mean of the relative improvement in PFWD was calculated for both treatment groups in all identified studies. The effect of the drug was assessed compared with placebo on final walking distance (WDf) using multilevel and random-effect models and adjusting for baseline walking distance (WD0). For the responder analysis, therapeutic success was defined as an improvement of walking distance of at least 50%.

MAIN RESULTS

We included seven studies in the IPD (n = 1266 patients). One of these studies (n = 183) was only used in the sensitivity analysis so that the main analysis included 1083 patients. The ratio of the relative improvement in PFWD (naftidrofuryl compared with placebo) was 1.37 (95% confidence interval (CI) 1.32 to 1.51, P < 0.001). The absolute difference in responder rate, or proportion successfully treated, was 22.3% (95% CI 17.1% to 27.6%). The calculated number needed to treat was 4.5 (95% CI 3.6 to 5.8).

AUTHORS' CONCLUSIONS

Naftidrofuryl has a statistically significant and clinically meaningful effect of improving walking distance in the six months after initiation of therapy for people with intermittent claudication. Access by researchers to data from RCTs that is suitable for IPD analysis should be possible through repositories of data from pharmacological trials. Regular formal appraisal of the balance of risk and benefit is needed for older pharmaceutical products.