Characterization of the CNS effects of naftidrofuryl (Praxilène) by quantitative EEG and functional MRI: a study in healthy elderly subjects

In the present study, we investigated the effects of a single and a repeated (5 days) administration of naftidrofuryl, a serotonin 5-HT2 receptor inhibitor having neuroprotective properties, on functional brain physiology in male healthy elderly subjects, using quantitative electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). Twelve subjects aged 60 +/- 3.8 years completed the quantitative EEG study, where the effects of 400 and 600 mg were assessed, and 12 other subjects (aged 56 +/- 4.7 years) completed the fMRI study, where the effect of 400 mg was assessed on the brain activation induced by the continuous performance test (CPT). Naftidrofuryl induced a transient reduction in alpha activity followed by a specific synchronisation of the 9.5- to 11-Hz EEG activity most pronounced after repeated administration. Such regimen also increased the CPT-induced brain activation visualized by way of fMRI. The results of the present study can be interpreted at the functional level that naftidrofuryl induced an improved level of vigilance or an increased capacity of alertness in healthy elderly subjects.

Naftidrofuryl in the treatment of vascular dementia

The design of this study was based on the European guidelines for the treatment of Alzheimer's disease. After a placebo run-in period of 4 weeks, patients with a diagnosis of vascular dementia (VaD) were randomised to receive either 400 mg naftidrofuryl/day, 600 mg naftidrofuryl/day or placebo for 6 months. The patients were assessed using the ADAS-cog, the SCAG, the NOSGER and the CGI item 2 scale. The primary analysis was undertaken on the ITT population. At the end of the study, significantly more patients in the treatment groups showed no deterioration on both ADAS-cog and SCAG scales compared with placebo (400 mg p = 0.005, 600mg p = 0.015). There were also significant differences between the active and placebo groups for the individual scales. This study has demonstrated that treatment with naftidrofuryl can slow the rate of deterioration of patients with vascular dementia.

A new study demonstrates the efficacy of naftidrofuryl in the treatment of intermittent claudication. Findings of the Naftidrofuryl Clinical Ischemia Study (NCIS)

BACKGROUND

The efficacy and safety of naftidrofuryl were assessed in a double blind, placebo controlled, parallel group study, in patients presenting with intermittent claudication, according to the latest European guidelines.

METHODS

The outpatients selected were of both sexes, aged 35 to 85, with moderately severe chronic, stable intermittent claudication and a pain-free (PFWD) and maximum walking distance (MWD) on the treadmill of between 100 and 300 metres. They received naftidrofuryl 200 mg tid or placebo for six months and were then assessed during a six-month follow-up period without treatment. The primary outcome measures were the pain-free walking distance and maximum walking distance.

RESULTS

Of the 221 selected patients, 196 were randomised and 181 entered the intention-to-treat analysis. The two groups were well matched for demographic variables, risk factors and history of vascular disease. After six months of treatment, patients who received naftidrofuryl had a 92% im-provement of geometric pain-free walking distance versus 17% in the placebo group (p < 0.001) and an 83% improvement of geometric maximum walking distance versus 14% in the placebo group (p < 0.001). During the follow-up period without treatment, the walking distances of the patients in the naftidrofuryl group significantly decreased. The incidence of adverse events was similar in the two groups.

CONCLUSIONS

This study demonstrated the efficacy of naftidrofuryl versus placebo in patients with intermittent claudication with a highly significant and clinically relevant difference and confirmed its good safety profile.

Influence of age on the pharmacokinetics of naftidrofuryl after single oral administration in elderly versus young healthy volunteers

The aim of this study was to evaluate and compare the pharmacokinetics of naftidrofuryl (CAS 3200-06-4) after single oral administration of a 200 mg naftidrofuryl tablet (Praxilene) in Caucasian male and female elderly healthy volunteers versus young healthy volunteers. Thirty healthy volunteers were included in a randomised phase I trial in 3 parallel groups of 10 subjects aged 18-35 years (group 1), 60-70 years (group 2) and 70-80 years (group 3). Blood samples were taken over a period of 24 h after dosing for evaluation of the pharmacokinetics of naftidrofuryl. The Cmax, tmax, AUC0-t parameters were measured and t1/2 and AUC0-alpha were calculated by a model independent method. The mean (+/- SD) pharmacokinetic parameters of naftidrofuryl after single oral administration of 200 mg of naftidrofuryl for group 1 were as follows: tmax 3.5 h (median), Cmax 284 +/- 136 ng/ml, t1/2 3.69 +/- 1.30 h, AUC0-t 1865 +/- 905 h.ng/ml and AUC0-inf 2055 +/- 901 h.ng/ml; for group 2: tmax 2.75 h (median), Cmax 282 +/- 165 ng/ml, t1/2 3.03 +/- 1.08 h, AUC0-t 1783 +/- 1147 h.ng/ml and AUC0-inf 1856 +/- 1158 h.ng/ml; for group 3: tmax 2.5 h (median), Cmax 271 +/- 86 ng/ml, t1/2 3.50 +/- 1.29 h, AUC0-t 1742 +/- 544 h.ng/ml and AUC0-inf 1834 +/- 549 h.ng/ml. Statistical analysis was performed on the pharmacokinetic parameters with one-way ANOVA in order to compare each age group. The results of the pharmacokinetic and statistical analysis showed no significant difference between each age group. The mean pharmacokinetic parameters of naftidrofuryl after single oral administration of 200 mg of naftidrofuryl in the whole population were as follows: tmax 2.75 h (median), for Cmax 279 +/- 128 ng/ml, t1/2 3.41 +/- 1.22 h, AUC0-t 1797 +/- 870 h.ng/ml for AUC0-inf 1910 +/- 877 h.ng/ml. In conclusion, advanced age did not appear to influence the pharmacokinetic profile of oral naftidrofuryl, and therefore it is not necessary to adjust the dosage of naftidrofuryl in this population.

The effect of naftidrofuryl on transcutaneous oxygen tension during a treadmill test in patients with peripheral arterial occlusive disease

Tissue hypoxaemia can be evaluated by the noninvasive method of transcutaneous oxygen tension (tcpO2) measurement in patients with peripheral arterial occlusive disease (PAOD). The effects of naftidrofuryl (Praxilene) on exercise-induced tissue ischaemia was objectively assessed by continuously measuring the tcpO2 in 30 patients during three treadmill tests over a 3-month period in a randomized double-blind, placebo controlled, parallel group study. To be included in the study, the tcpO2 and total walking distance had to be stable during the washout period (D-15-D0). The area under the tcpO2 curves was scanned and automatically calculated after identification of baseline and the end of the treadmill test. The treadmill test on D30 and D90 was terminated at a similar walking distance to that obtained on D0. On D0 both groups were comparable (p = 0.22). The area under the curve (AUC) reduced significantly in the naftidrofuryl group between D0 and D30 (p < 0.001) and D0 and D90 (p < 0.001). However, no significant tcpO2 AUC reduction was found in the placebo group (D0-D30, p = 0.58; D0-D90, p = 0.50). This was confirmed by calculation of the percentage of patients whose percentage change in the AUC on D90 was higher than the upper limit of the 90% confidence interval, calculated from the percentage change over the washout period. Of the 15 patients receiving natfidrofuryl, 66.6% exceeded this upper limit, compared with only 7% of patients receiving placebo (p = 0.0017). This study shows that naftidrofuryl has a protective effect on exercise-induced tissue ischaemia as measured by the tcpO2 AUC in PAOD stage II patients.

The effect of naftidrofuryl on intermittent claudication: a meta-analysis

A meta-analysis was performed on four clinical trials, conducted during 1980-1989 in France (two trials) and in the Federal Republic of Germany (two trials). Altogether, 596 patients with peripheral arterial occlusive disease (Fontaine's classification stage II) entered these four multicenter studies. Four hundred fifty-two patients completed the trials, 241 were treated with 600 mg naftidrofuryl orally per day and 211 were given a placebo. The studies were of a double-blind parallel design and lasted for 3 or 6 months. Inclusion and exclusion criteria were comparable, as were the experimental methods used. Occasionally, differences in study design and methods were observed. Risk factors were recorded in three of the four studies. The outcome criterion of pain-free walking distance was studied for the four trials together and showed a significant improvement in the active drug tested group, following both 3- and 6-month duration of treatment. The type of treatment, the severity of the disease, the existence of blood lipid disorders, and smoking were found to be the predictive factors associated with the evolution of pain-free walking distance during 3 months. The meta-analysis confirms the beneficial effect of naftidrofuryl in treating peripheral arterial occlusive disease.