ACENOCOUMAROL

Absorption

Rapidly absorbed orally with greater than 60% bioavailability. Peak plasma levels are attained 1 to 3 hours following oral administration.

Toxicity

The onset and severity of the symptoms are dependent on the individual's sensitivity to oral anticoagulants, the severity of the overdosage, and the duration of treatment. Bleeding is the major sign of toxicity with oral anticoagulant drugs. The most frequent symptoms observed are: cutaneous bleeding (80%), haematuria (with renal colic) (52%), haematomas, gastrointestinal bleeding, haematemesis, uterine bleeding, epistaxis, gingival bleeding and bleeding into the joints. Further symptoms include tachycardia, hypotension, peripheral circulatory disorders due to loss of blood, nausea, vomiting, diarrhoea and abdominal pains.

Chemical properties

White Crystalline Solid

Originator

Sintrom ,Geigy ,US ,1957

The Uses of ACENOCOUMAROL

R-Enantiomer of Acenocoumarol. Vitamin K antagonist; structurally similar to Warfarin. Anticoagulant

The Uses of ACENOCOUMAROL

S-Enantiomer of Acenocoumarol. Vitamin K antagonist; structurally similar to Warfarin. Anticoagulant

The Uses of ACENOCOUMAROL

antimicrobial

The Uses of ACENOCOUMAROL

Anticoagulant agent: Vitamin K antagonist

What are the applications of Application

Acenocoumarol is an anticoagulant vitamin K antagonist

Background

Acenocoumarol is a coumarin derivative used as an anticoagulant. Coumarin derivatives inhibit the reduction of vitamin K by vitamin K reductase. This prevents carboxylation of vitamin K-dependent clotting factors, II, VII, IX and X, and interferes with coagulation. Hematocrit, hemoglobin, international normalized ratio and liver panel should be monitored. Patients on acenocoumarol are prohibited from giving blood.

Indications

For the treatment and prevention of thromboembolic diseases. More specifically, it is indicated for the prevention of cerebral embolism, deep vein thrombosis, pulmonary embolism, thromboembolism in infarction and transient ischemic attacks. It is used for the treatment of deep vein thrombosis and myocardial infarction.

Definition

ChEBI: A hydroxycoumarin that is warfarin in which the hydrogen at position 4 of the phenyl substituent is replaced by a nitro group.

Manufacturing Process

16 parts of 4-hydroxycoumarin and 19 parts of 4-nitrobenzalacetoneare thoroughly mixed and heated for 12-14 hours in an oil bath, the temperature of which is between 135°C and 140°C. After cooling, the melt is dissolved in a little acetone. The solution is slowly added to a lye made up from 6 parts of sodium hydroxide in 400 parts of water while stirring and then the mixture is stirred for 30 minutes. A little animal charcoal is then added, the mixture is stirred for a further 15 minutes, 400 parts of water are added and the charcoal and undissolved components are separated by filtration under suction. The clear solution is made acid to Congo red paper with hydrochloric acid and the product which is precipitated is filtered off under suction. 3-[α- (4'-Nitrophenyl)-β-acetylethyl]-4-hydroxycoumarin is obtained. MP 196-199°C.
It should be noted that the process is akin to that for Warfarin except that 4- nitrobenzalacetone replaces benzalacetone as a raw material.

Therapeutic Function

Anticoagulant, Vitamin

Pharmacokinetics

Acenocoumarol inhibits the reduction of vitamin K by vitamin K reductase. This prevents carboxylation of certain glutamic acid residues near the N-terminals of clotting factors II, VII, IX and X, the vitamin K-dependent clotting factors. Glutamic acid carboxylation is important for the interaction between these clotting factors and calcium. Without this interaction, clotting cannot occur. Both the extrinsic (via factors VII, X and II) and intrinsic (via factors IX, X and II) are affected by acenocoumarol.

Clinical Use

Anticoagulant

Safety Profile

Poison by intraperitoneal route.Moderately toxic by ingestion. A human teratogen by anunspecified route. When heated to decomposition it emitstoxic fumes such as NOx.

Synthesis

Acenocoumarin, 3-(α-acetonyl-p-nitrobenzyl)-4-hydroxycoumarin (24.1.11), is synthesized by a scheme completely analogous to making warfarin, but using p-nitrobenzalacetone.

Drug interactions

Potentially hazardous interactions with other drugs There are many significant interactions with coumarins. Prescribe with care with regard to the following:
Anticoagulant effect enhanced by: alcohol, amiodarone, anabolic steroids, aspirin, aztreonam, bicalutamide, cephalosporins, chloramphenicol, cimetidine, ciprofloxacin, fibrates, clopidogrel, cranberry juice, danazol, dipyridamole, disulfiram, dronedarone, esomeprazole, ezetimibe, fibrates, fluconazole, flutamide, fluvastatin, grapefruit juice, itraconazole, ketoconazole, levamisole, levofloxacin, macrolides, methylphenidate, metronidazole, miconazole, nalidixic acid, neomycin, norfloxacin, NSAIDs, ofloxacin, omeprazole, pantoprazole, paracetamol, penicillins, propafenone, ritonavir, rosuvastatin, SSRIs, simvastatin, sulfinpyrazone, sulphonamides, tamoxifen, testosterone, tetracyclines, thyroid hormones, tigecycline, toremifene, tramadol, trimethoprim, valproate, vitamin E, voriconazole.
Anticoagulant effect decreased by: acitretin, azathioprine, carbamazepine, enteral feeds, enzalutamide, fosphenytoin, griseofulvin, oral contraceptives, phenobarbital, phenytoin, primidone, rifamycins, St John’s wort (avoid), sucralfate, vitamin K.
Anticoagulant effects enhanced / reduced by: anion exchange resins, corticosteroids, dietary changes, efavirenz, fosamprenavir, tricyclics.
Analgesics: increased risk of bleeding with IV diclofenac and ketorolac - avoid concomitant use.
Anticoagulants: increased risk of haemorrhage with apixaban, dabigatran, edoxaban and rivaroxaban - avoid.
Antidiabetic agents: enhanced hypoglycaemic effect with sulphonylureas also possible changes to anticoagulant effect.
Ciclosporin: there have been a few reports of altered anticoagulant effect; decreased ciclosporin levels have been seen rarely.
Cytotoxics: increased risk of bleeding with erlotinib; enhanced anticoagulant effect with capecitabine, etoposide, fluorouracil, ifosfamide, sorafenib and tegafur; reduced effect with mercaptopurine and mitotane.

Metabolism

Extensively metabolized in the liver via oxidation forming two hydroxy metabolites and keto reduction producing two alcohol metabolites. Reduction of the nitro group produces an amino metabolite which is further transformed to an acetoamido metabolite. Metabolites do not appear to be pharmacologically active.

Metabolism

Acenocoumarol is extensively metabolised, although the metabolites appear to be pharmacologically inactive in man. 29% is excreted in the faeces and 60% in the urine, with less than 0.2% of the dose being renally excreted unchanged.