Safety aspects of a coumarin-troxerutin combination regarding liver function in a double-blind placebo-controlled study.

OBJECTIVE: Coumarin is reported to elevate liver function tests (LFT) values. In a prospective, placebo-controlled, clinical trial, efficacy and safety of a coumarin-containing combination (SB-LOT) were evaluated in the treatment of chronic venous insufficiency. Here, we report on the drug safety of coumarin with special respect to liver reaction. METHODS: 114 patients were treated with SB-LOT (30 mg coumarin and 180 mg troxerutin t.i.d.) and 117 with placebo during a period of 16 weeks. LFT values (ALT, AST, AP and gamma-GT) were monitored at baseline, 4, 6, 8, 12 and 16 weeks of therapy. Adverse drug reactions were assessed regarding causality. Additionally, lymphocyte proliferation test was used to identify allergic reactions. Logistic regression analysis was performed to identify possible risk factors. RESULTS: No serious adverse drug reactions occurred. Elevations of LFT were assessed as biochemical abnormality. Specific clinical symptoms such as jaundice did not occur. Only 1 patient reported fatigue and exhaustion. Logistic regression estimated a basic risk for elevation of LFT of 4.9% under SB-LOT and 2.1% under placebo. Hepatitis in the history and diseases of the liver were identified as risk factors. CONCLUSION: This evaluation contributes to safety data of SB-LOT in man. LFT elevation is transient and the low risk of the SB-LOT therapy to increase LFT value can be limited when risk factors are considered.

Single copy of variant CYP2A6 alleles does not confer susceptibility to liver dysfunction in patients treated with coumarin.

OBJECTIVE: Coumarin, used in the treatment of chronic venous diseases, is mainly metabolized to non-toxic 7-hydroxy-coumarin by CYP2A6. At least, 3 variant alleles, CYP2A6*2, CYP2A6*3 and CYP2A6*4A, have been shown to encode catalytically defective proteins. Sporadic elevation of liver enzymes has been reported on the chronic administration ofcoumarin. We sought to determine if susceptibility to coumarin-associated liver dysfunction is genetically determined by polymorphism in CYP2A6 and impairment of the 7-hydroxylation ofcoumarin. Additionally, we were interested in the effect of polymorphism on smoking because of the predominant role of CYP2A6 in the metabolism of nicotine. METHODS: The investigation was performed prospectively within a randomized double-blind clinical trial of the coumarin-containing drug SB-LOT (90 mg coumarin + 540 mg troxerutin/d) vs. placebo in 231 German patients with chronic venous insufficiency. Monitoring of the hepatic status involved regular measurements of liver function during the 16-week treatment. Genotyping of CYP2A6 was carried out by means of PCR and confirmed by DNA sequencing analysis. RESULTS: The allelic frequencies of the variant CYP2A6*2 and CYP2A6*3 alleles were 0.023 and 0.014, respectively. There was no significant difference in the incidence of liver dysfunction between heterozygotes with CYP2A6*2, CYP2A6*3 and wild-type homozygotes. CYP2A6 polymorphism had no significant effect on smoking behavior. CONCLUSION: No evidence was obtained that the studied polymorphism in CYP2A6 is a determinant of the coumarin-associated liver dysfunction.

The efficacy and safety of a coumarin-/troxerutin-combination (SB-LOT) in patients with chronic venous insufficiency: a double blind placebo-controlled randomised study.

BACKGROUND: The objective was to evaluate the oedema-protective effect of a vasoactive drug (coumarin/troxerutin [SB-LOT]) plus compression stockings in patients suffering from chronic venous insufficiency after decongestion of the legs as recommended by the new guidelines. PATIENTS AND METHODS: 231 patients were randomly assigned medical compression stockings plus SB-LOT (90 mg coumarin and 540 mg troxerutin per day) or medical compression stockings plus placebo for the first 4 weeks and SB-LOT or placebo for the second 12 weeks of the study. The primary efficacy endpoint was the lower leg volume measured by well-established water plethysmometry. RESULTS: 226 patients were evaluated. After ceasing compression stockings, an edema protective effect was detected in the SB-LOT-group but not in the controls. Recurrence of leg volume increase was by 6.5 +/- 12.1 ml and by 36.7 +/- 12.1 ml in the SB-LOT and placebo group, respectively (p = 0.0402). The local complaint score and general aspects of quality of life were also superior for the SB-LOT-group (p = 0.0041). Significant differences were also observed with regard to clinical global impression and therapeutic effect. No serious adverse drug reaction or clinically relevant impairment of laboratory parameters occur. CONCLUSION: This study confirms the oedema-protective effect of SB-LOT in chronic venous insufficiency and provides a treatment option for patients who discontinue compression after a short time.

Prophylaxis of radiogenic sialadenitis and mucositis by coumarin/troxerutine in patients with head and neck cancer--a prospective,randomized, placebo-controlled, double-blind study.

OBJECTIVE: To study the efficacy of coumarin/troxerutine for the protection of salivary glands and mucosa during irradiation. DESIGN: Prospective, randomized, placebo-controlled, double-blind trial. SETTING: University hospital, Germany. PATIENTS: 48 patients who had radiotherapy to the head and neck. MAIN OUTCOME MEASURES: Salivary gland scintigraphy and acute side-effects of radiotherapy (Radiation Therapy Oncology Group (RTOG) score). RESULTS: 23 patients (11 experimental, 12 placebo) completed the study. The global efficacy measure combining scintigraphy and RTOG score favoured the experimental arm (P=0.07). The RTOG score showed significantly fewer acute side-effects of radiation in the experimental arm (P<0.05). CONCLUSION: The results suggest that coumarin/troxerutine have a favourable effect in the treatment of radiogenic sialadenitis and mucositis.

[Prospective double-blind study of prophylaxis of radioxerostomia with Coumarin/Troxerutine in patients with head and neck cancer]. / Prospektive, doppelblinde Therapiestudie zur Prophylaxe der Radioxerostomie durch Cumarin/Troxerutin bei Patienten mit Kopf-Hals-Karzinomen.

AIM: Prospective, randomized placebo-controlled double-blind study to prove the efficacy of Coumarin/Troxerutine (Venalot Depot) for protection of salivary glands during a head and neck irradiation. PATIENTS AND METHOD: Forty-eight radiotherapy patients (60 Gy) with head and neck cancer were included in this trial. During radiotherapy the salivary glands were located in the core irradiation field. Primary efficacy parameters were sialometry, quantitative salivary gland scintigraphy and clinical evaluation of early effects of radiotherapy (RTOG-score, Table 1). All data were collected at 6 assessments: 1 week pre-radiation (U1), at start (U2), half time (U3) and end (U4) of irradiation, 8 days (U5) and 28 days (U6) after the end of irradiation (Figure 1). RESULTS: Twenty-three patients (11 verum, 12 placebo) completed the study with all assessments. Sialometrically, all patients were severely (half of radiotherapy) or completely (end of radiotherapy) xerostomatic (Figure 2). In a global efficacy measure according to O'Brien combining scintigraphy and RTOG there was a tendency for a higher efficacy of verum compared to placebo (p = 0.068). After start of irradiation therapy, the RTOG-score showed continuously and significantly lower early radiation effects under verum than under placebo (U3 vs U6: p < 0.05, area under curve: p = 0.032; Table 2, Figure 3). The scintigraphically determined excretion fraction was slightly less impaired in the verum group compared to the placebo treatment (p = 0.12. Figure 4). There was no difference in drug safety between placebo and verum for adverse events, changes in the activity of liver enzymes and for global impression of tolerability. CONCLUSIONS: The results give support for an advantageous effect of Venalot Depot in the treatment of radiogenic sialadenitis and mucositis. In even a small number of evaluable patients, early clinical effects of irradiation (RTOG-score) were less pronounced in the active treatment group than in the placebo group, but the sample size was too low to prove statistically also the benefit of coumarin/troxerutine with the scintigraphic method. Sialometry seems not suitable for the assessment of early radiation effects.

Evaluation of the safety of a coumarin-troxerutin combination.

Concerns about liver reactions reported for coumarin preparations prompted a re-evaluation of the combination of coumarin with troxerutin, widely used since 1971 in Germany. No evidence of liver toxicity could be found in available clinical research data. We estimated the number of coincidental cases of unexplained clinically apparent liver disease expected to arise during the patient treatment time on the basis of sales and the maximal recommended daily dosage. A comparison to the number of spontaneous reports yielded reassuring results.

Locoregional administration of 5-fluoro-2'-deoxyuridine (FdUrd) in Novikoff hepatoma in the rat: effects of dose and infusion time on tumor growth and on FdUrd metabolite levels in tumor tissue as determined by 19F-NMR spectroscopy.

The influence of infusion time and dose on the anticancer efficacy of 5-fluoro-2'-deoxyuridine (FdUrd) was investigated using a locoregional therapy model: Novikoff hepatoma transplanted i.m. into the thigh of Wistar rats and FdUrd infusion via a catheter implanted in the femoral artery. In experiment A the FdUrd dose (five daily doses of 12, 19 and 30 mg/kg) and the duration of administration (bolus, 1 h, 5 h, and 24 h) were varied. The change in tumor volume following treatment and the number of rats showing regression vs progression served as indicators of therapy response. The results showed a clear dose dependence, and for each infusion time the 30 mg/kg dose was the most effective, without any signs of general toxicity. At this dose the longest infusion time (24 h) was less effective (regression in three of six rats) compared with 1-h or 5-h treatments (four of five in regression). In experiment B either one or five daily FdUrd doses (15, 30, 60 mg/kg) were administered i.a. for the same infusion times used in experiment A. After treatment, tumors were explanted ex vivo and approximately 1-g tissues samples were immediately frozen in liquid nitrogen for storage. 19F-NMR spectroscopy at 11.7 T was used to quantify FdUrd metabolites [5-fluorouracil (FUra), alpha-fluoro-beta-alanine (F beta Ala), 5-fluorouracil nucleosides and nucleotides (F-Nuc)] in the solid tumor tissue samples (maintained at 4 degrees C) with a detection threshold of about 5 nmol/g. The metabolite signal pattern indicated that FdUrd is first converted to FUra, followed by anabolism primarily to nucleotides in the oxy form (e.g. FUTP). The total amount of fluorine detected in tumor tissue increased with dose and decreased with infusion time. For all treatments FNuc could be detected, even after 24 h infusion, and their levels showed a good linear correlation with the total F. The major catabolite F beta Ala was present in tumor at low levels that correlated poorly with total F, indicating recirculation from other organs (e.g. liver) as the main source. Thus, the NMR method can provide detailed information regarding the efficiency of locoregional treatment (catheter function, drug uptake and metabolism). Initial results of non-invasive in vivo NMR experiments are also presented.