Platelet function and prostaglandins in patients with peripheral vascular disease treated with calcium dobesilate

Pharmacology of Oedema Protective Drugs

Objective:

To review the drugs used in the treatment of chronic venous diseases of the lower limb.

Data sources:

Published papers referring to the pharmacology of drugs used in the management of chronic venous insufficiency and varicose veins of the lower limb.

Study selection:

Sixty-four papers referring to the use of horse chestnut extract (aescin), flavonoids, tribnoside and calcium dobesilate have been included.

Data extraction:

Papers were examined to establish the mechanism of action of ‘oedema protective’ drugs.

Data synthesis:

Oedema protective drugs modify the permeability of the microcirculatory endothelium in animal models of oedema and probably in patients with venous disease to reduce transcapillary loss of fluid into the tissues. The exact mechanisms of action remain unclear.

Conclusion:

Animal and clinical studies demonstrate that drugs of the four types included in this review moderate the development of tissue oedema.

Therapeutic effects of calcium dobesilate on diabetic nephropathy mediated through reduction of expression of PAI-1

The aim of this study was to investigate whether calcium dobesilate (calcium dihydroxy-2,5-benzenesulfonate) may be used to treat diabetic nephropathy. A total of 121 patients with type 2 diabetic nephropathy received calcium dobesilate (500 mg, 3 times a day) for 3 months. The levels of glycated hemoglobin, fasting serum C peptide, triglyceride, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, alanine aminotransferase, γ-glutamyl transferase, urea nitrogen, creatinine, hematocrit, plasma viscosity, whole blood reduced viscosity, high, medium and low shear rate whole blood viscosity, fibrinogen, plasminogen activator inhibitor-1 (PAI-1) and endothelin were determined. The urinary albumin excretion rate (UAER) was also determined once a month during the study. The UAER and medium and low shear rate whole blood viscosity were significantly lower in the treated patients. The rate of microalbuminuria normalization was 90%. During the treatment, the UAERs decreased. The results revealed that calcium dobesilate has therapeutic effects on type 2 diabetes patients with microalbuminuria. In addition, the benefit was positively correlated with the calcium dobesilate treatment time. The therapeutic effect may be due to decreases in the levels of PAI-1.

The effect of calcium dobesilate on venous function following saphenectomy in coronary artery bypass grafting

BACKGROUND

The aim of this study was to determine whether prophylactic use of calcium dobesilate (CD) can improve venous function after saphenous vein harvest in coronary artery bypass graft (CABG).

MATERIALS AND METHODS

A total of 100 patients who underwent elective CABG were divided into four equal groups. In Group A, the greater saphenous vein (GSV) was harvested below the knee and, in Group B, through the knee till the groin. These patients remained untreated. Group C received CD in a dosage of 1500 mg po daily after the GSV was harvested below the knee. Group D received same dosage of CD after the GSV was harvested through the knee till the groin. Venous function of ipsilateral leg was evaluated clinically and by Doppler ultrasonography in the postoperative first week and second month.

RESULTS

Clinical findings of venous insufficiency were observed with a similar rate between groups at both early and late periods. In Groups A and B, after 2 months, flow velocities decreased and reflux periods increased significantly. In groups C and D, treatment with CD for 2 months after saphenectomy resulted in a significant increase in flow velocities and a significant decrease in reflux periods. Patients in Groups B and D have significantly more impaired venous functions.

CONCLUSION

Saphenectomy results in ipsilateral leg venous dysfunction, which seems to be unrelated to leg swelling and to be more prominent in patients with high-level saphenectomy. In addition, to be careful about the restriction of the saphenectomy procedure into the most appropriate level, prophylactic use of CD can prevent this deterioration when it was added to varice socks.

Safety of Calcium Dobesilate in Chronic Venous Disease, Diabetic Retinopathy and Haemorrhoids

The aim of the present review is to consider the adverse effects and the safety profile of calcium dobesilate. Calcium dobesilate (Doxium) is a veno-tonic drug, which is widely prescribed in more than 60 countries from Europe, Latin America, Asia and the Middle East for three main indications: chronic venous disease, diabetic retinopathy and the symptoms of haemorrhoidal attack. Data sources used for this review comprise the international literature (1970-2003), a postmarketing surveillance (PMS) report for calcium dobesilate from OM Pharma (Geneva, Switzerland) covering the period 1974-1998, and periodic safety update reports (PSUR) covering the period 1995-2003 from the French Regulatory authorities pharmacovigilance database and OM Pharma. Data from the PMS report for 1974-1998 indicated that adverse events with calcium dobesilate did not occur very frequently and had the following distribution in terms of frequency: fever (26%), gastrointestinal disorders (12.5%), skin reactions (8.2%), arthralgia (4.3%), and agranulocytosis (4.3%). No deaths were attributed to calcium dobesilate in the PMS report. Using data on product use in the Swiss Compendium we estimated the prevalence of agranulocytosis to be 0.32 cases/million treated patients, i.e. ten times less than the calculated prevalence of agranulocytosis in the general population. Most adverse events are type B, i.e. rare and unrelated to the pharmacological properties of calcium dobesilate. This review concludes that the risk of an adverse effect with calcium dobesilate 500-1500 mg/day is low and constant over time. The recently raised problem of agranulocytosis (a total of 13 known cases drawn from all data sources) appears to be related to methodological bias. Such a review reinforces the need for a strong international pharmacovigilance organisation using similar methods to detect and analyse the adverse effects of drugs.

Clinical evaluation of the efficacy and safety of calcium dobesilate in patients with chronic venous insufficiency of the lower limbs

Several venotonic drugs have been used in the treatment of chronic venous insufficiency (CVI) of the lower limbs, most of them from natural sources. Calcium dobesilate, from synthetic origin, has been shown to improve clinical symptoms of these venous conditions. Three hundred fifty-two patients with CVI in grades I and II of Widmer's classification were included from an open population between January 1999 and June 2000; patients received calcium dobesilate 500 mg every 8 hours for 9 weeks. A basal recording and recordings every 3 weeks were made of heaviness, pain, cramps, and paresthesias of the lower limbs with a severity scale, and edema was assessed by measurement of the circumference of ankles and calves. Two hundred eighty-six patients (81.3%) were women and 66 (18.7%) were men with a mean age of 45.7 +/-14.1 years; 200 patients (56.8%) were grade I and 150 (42.6%) were grade II of Widmer's classification, and two patients had no classification, with a mean duration of symptoms of 6.5 +/-7.4 years. All of the symptoms had a significant reduction from the first to the final visit of treatment; 70% of the patients complained of moderate to severe heaviness of the lower limbs at the beginning of the study, whereas 10% of the patients presented this symptom at the end of treatment. Likewise, 75%, 37%, and 41% of the patients, respectively, complained of moderate to severe pain, cramps, and paresthesias of the lower limbs at the beginning of the study, with a reduction in this prevalence to 6%, 2%, and 4%, respectively, at the end of treatment (p<0.001, Wilcoxon test). In regard to edema of ankles and calves, a significant reduction in circumferences was registered in both sites at the end of treatment; for instance, the mean circumference of the right ankle was reduced from 23.78 +/-0.27 to 22.71 +/-0.31 cm while the right calf had a reduction from 35.08 +/-0.41 to 33.83 +/-0.5 cm (p<0.001, paired t test). Side effects were registered in 17.9% of the patients. This trial shows that calcium dobesilate had significant efficacy in the improvement of all the symptoms in patients with CVI, achieving this effect with an acceptable safety profile.

Involvement of Nitric Oxide in the Inhibition of Aortic Smooth Muscle Cell Proliferation by Calcium Dobesilate

Vascular smooth muscle cell (SMC) proliferation is a key process in the pathogenesis of atherosclerosis. Numerous factors are involved in the regulation of SMC growth. Nitric oxide (NO) induces the inhibition of SMC proliferation whereas oxidized low-density lipoproteins (LDL) have a mitogenic effect. Calcium dobesilate (Doxium) is an angioprotective agent for treating vascular diseases. It has been shown to increase NO production and to have antioxidant properties but its mechanism of action is not yet fully understood. This study investigated the effect of calcium dobesilate on proliferation of rat aortic SMC in culture. Proliferation was evaluated by cell number and DNA synthesis. Orally administered calcium dobesilate (30, 100, or 200 mg/kg/day for 7 days) induced a dose-dependent decrease of proliferation of SMC in primary culture compared with controls. In vitro treatment with calcium dobesilate (0.05-5 mM) inhibited both DNA synthesis and proliferation in a time- and concentration-dependent manner. In both ex vivo and in vitro models, the inhibition was reversible upon removal of the drug. Calcium dobesilate also stimulated NO production and NO synthase activity. Inhibitors of NO synthesis attenuated the inhibitory effect of calcium dobesilate (300 µM) on DNA synthesis. In addition, calcium dobesilate (2.5-40 µM) induced a dose-dependent protection of cooper-induced LDL oxidation. These results showed that calcium dobesilate inhibits SMC proliferation, partly by a NO-dependent mechanism, and suggest that it could be effective in the treatment of pathological disorders associated with vascular SMC proliferation.

Effect of calcium dobesilate on the blood-retinal barrier in early diabetic retinopathy

The effect of calcium dobesilate on the alteration of the blood-retinal barrier was studied in 41 adult-onset, non-insulin dependent diabetic patients with minimal or no retinopathy, randomly assigned to receive either oral calcium dobesilate (1000 mg twice daily) or a placebo for 12 months. The posterior vitreous value and the penetration ratio, determined by vitreous fluorophotometry, reflected stabilisation of blood-retinal barrier permeability in the calcium dobesilate patients and deterioration of blood retinal barrier in those given placebo. During the relatively short period of the study, one year, no significant change in microaneurysm and capillary closure gradings was observed. No side effects were associated with calcium dobesilate.