Comparison of a new microcrystalline dicoumarol preparation with warfarin under routine treatment conditions

1 To determine whether two different oral anticoagulants show difference under routine clinical conditions, 71 patients were randomized to treatment with Apekumarol, a microcrystalline dicoumarol preparation, and 72 patients to treatment with warfarin. 2 During the inpatient phase of treatment both drug groups remained for about 94% of their treatment time within prothrombin value limits of 5-25% (Simplastin A). No statistically significant difference was found between the drugs. 3 While under outpatient care, both drug groups remained for about 80% of their treatment time within prothrombin value limits of 5-25%. No statistically significant difference was found between the drugs. 4 The intensity of control and number of prothrombin-determinations did not differ significantly between the groups. 5 Variations in the daily dose did not differ significantly between the groups. 6 The mean daily dose could not be correlated to mean body weight. 7 The mean daily dose decreased with age for the male patients taking warfarin, not for the female patients. There was no such decrease for either male or female patients taking Apekumarol. An additional 137 patients who at the time of the trial were under routine treatment with warfarin were also studied with regard to mean daily dose, age and sex. In this additional group the mean daily dose could be correlated with age in both males and females. 8 No difference between Apekumarol and warfarin could be demonstrated when tested under routine clinical conditions according to the design of the present study. Sensitivity for warfarin, but not for Apekumarol, seems to increase with age, this sensitivity has been demonstrated in both sexes.

[Comparative evaluation of the methods of treatment of acute thrombosis of the main veins]

The experience with antithrombotic conservative treatment of 102 cases of acute thrombosis in the inferior vena cava system and in the deep veins of the lower extremities is generalized here. The suggested method permits to do away with thrombotic condition of hemostasis at a minimal risk of the occurrence of hemorrhagic complications.

Effect of heptabarbital on bioavailability of bishydroxycoumarin in the rat

The influence of oral administration of heptabarbital on the gastrointestinal absorption of bishydroxycoumarin (BHC) was investigated in rats. Pretreatment of the animals with 20 mg/kg heptabarbital twice dialy for three days prior to the administration of 50 mg/kg BHC resulted in a 40% decrease from controls in the area under the BHC plasma concentration time curve (AUC). Preliminary studies indicated that a similar decrease in gastrointestinal absorption of BHC could be seen following a single oral dose of heptabarbital administered concomitantly with the anticoagulant.

[Long-term results of prolonged dicoumarol anticoagulant therapy in 327 peipheral arteriopathic subjects]

327 patients with peripheral arteriopathy were treated solely with protracted dicoumarol anticoagulant therapy. The indication for such therapy was applied not only in patients in whom the high risk and poor run-off contraindicated revascularisation operations, but also in those in good general conditions at the 2nd or 3rd stage with iliac and femoral thromboses. Two-thirds of the arteriopathics observed were given the anticoagulant treatment for more than two years, with a maximum of eight years. Clinical evolution of the disease is discussed in relation to the treated patients' age and stage, while emphasis is given to the very low incidence of complications and contraindications, despite the long period of treatment.

Repeated oral administration of coumaphos in sheep: interactions of coumaphos with bishydroxycoumarin, trichlorfon, and phenobarbital sodium

Interactions between treatments with coumaphos, bishydroxycoumarin (an anticoagulane), trichlorfon (an organophosphorous compound), and phenobarbital sodium (an inducer of microsomal enzymes) were investigated in sheep. A daily dose of 2 mg of coumaphos/kg of body weight for 6 days did not affect the plasma enzymes or the antiprothrombinemic effect of bishydroxy-coumarin in wethers. The treatment of ewes with an intravenous (IV) injection of trichlorfon, insufficient to produce significant inhibition of erythrocyte acetylcholinesterase (AChE) activity, appeared to produce additive effects with those produced by subsequent treatment with 4 mg of coumaphos/kg/day. In ewes given 40 mg of phenobarbital sodium/kg for 5 days intraperitoneally (IP), the anticholinesterase effect of 4 mg of coumaphos/kg was significantly reduced and signs of toxicity were not present. Treatment with daily doses of 2 mg of coumaphos/kg for 6 days did not modify the anticholinesterase effect of a 2nd series of treatments given 6 weeks later.

Anomalous results of studies on drug interaction in man. II. Halofenate (mk-185) and antipyrine, bishydroxycoumarin, and warfarin

Three highly reproducible experiments on drug interaction in normal human volunteers provided anomalous results: chronic halofenate administration shortened plasma antipyrine and bishydroxycoumarin half-lives but prolonged plasma warfarin half-lives. This dissociation in the effect produced by a chronically administered drug on the metabolism of test drugs has not previously been reported in man. Chronic halofenate administration to rats, mice and dogs stimulated several hepatic microsomal drug-metabolizing systems, including those responsible for bishydroxycoumarin warfarin hydroxylation.