Anticoagulant from the group of vitamin K antagonists. The mechanism of action of drugs from this group is to inhibit the synthesis of clotting factors: II, VII, IX and X. Their absence causes inhibition of haemostasis.

Indications for the use of acenocoumarol

The main purpose of using oral anticoagulants is to prevent the build-up of blood clots and reduce the risk of thromboembolic complications.

Vitamin K antagonists do not dissolve the blood clots formed. The prothrombin time should be measured at the same time every day, both before starting treatment and until the coagulation parameters have stabilized.

Dosage of acenocoumarol

Acenocoumarol should be taken once a day at the same time.

Dosage is individualized based on prothrombin time INR (International Normalized Ratio) determinations.

If this ratio is within the normal range (between 0.8-1.2), the administration of the vitamin K antagonist may be started with a loading dose of 6 mg per day on the first day, followed by a dose of 4 mg per day.

A loading dose is not necessary for people of a he althy body weight and treatment can be started with a dose of 2 to 4 mg per day.

The maintenance dose is also determined on the basis of careful analysis of the INR test results, which the patient should check once or twice a month after stabilization. Only a meticulous determination of INR enables the selection of an appropriate dose adjusted to the disease, clinical indications and the patient's response to acenocoumarol. The usual maintenance dose is in the range of 1 to 8 mg per day.

In high-risk patients (eg after a myocardial infarction), it is necessary to gradually withdraw the dose due to the risk of "rebound clots". In the remaining patients, there is no need to gradually reduce the dose.

If you miss a dose on the previous day, do not double the dose, but it may be necessary to consult a doctor.

Acenocoumarol can be used in children, however, special care should be taken and INR should be measured more often. Dosage reduction may be necessary in the elderly.

Contraindications tothe use of acenocoumarol

Acenocoumarol is not intended for:

  • pregnant people,
  • people with a hemorrhagic diathesis,
  • people before procedures (increased risk of bleeding),
  • people with peptic ulcer disease,
  • people with renal insufficiency,
  • people with severe hypertension.

Be especially careful:

  • in the case of digestive tract disorders that may affect the absorption of acenocoumarol,
  • in people suspected of protein C or S deficiency,
  • in the case of intramuscular injections that may cause hematomas,
  • in people who are breastfeeding, give your baby vitamin K prophylactically.

Acenocoumarol and diet

Patients should be advised of the need to maintain a proper diet with a limited amount of vitamin K products that weaken the effects of acenocoumarol.

The products that should be restricted include:

  • cruciferous vegetables,
  • lettuce,
  • spinach,
  • chicory,
  • kale,
  • raw parsley,
  • peaches.

Also, products such as:

should not be consumed in large amounts:
  • avocado,
  • liver
  • or soybeans.

Interaction with other medicinal substances

The list of substances that interact with acenocoumarol is very long, so it is extremely important to notify your physician of all medications you are taking (dietary supplements, over-the-counter medications, and medications prescribed by other physicians).

These interactions may lead to a decrease in the effect of acenocoumarol and thromboembolic complications as well as increase its concentration in the body, thus increasing the risk of bleeding.

The anticoagulant effect of acenocoumarol intensifies:

  • allopurinol,
  • anabolic steroids,
  • androgens,
  • antiarrhythmic drugs (e.g. amiodarone, quinidine),
  • broad-spectrum antibiotics (e.g. amoxicillin),
  • macrolide antibiotics,
  • erythromycin,
  • clarithromycin,
  • quinolones (e.g. ciprofloxacin, norfloxacin, ofloxacin),
  • tetracyclines,
  • neomycin,
  • chloramphenicol,
  • fibrates (e.g. clofibric acid, its derivatives and structural analogs, e.g. fenofibrate, gemfibrozil),
  • disulfiram,
  • glucagon,
  • drugs with an antagonistic effect on the H2 receptor (e.g. cimetidine),
  • sulfonamides including co-trimoxazole (sulfamethoxazole and trimethoprim),
  • imidazole derivatives (e.g. metronidazole, including topical miconazole),
  • paracetamol,
  • oral antidiabetic drugs (e.g. glibenclamide),
  • thyroid hormones (including dextrothyroxin),
  • statins (e.g. simvastatin, atorvastatin, fluvastatin),
  • SSRI- serotonin reuptake inhibitors (e.g. citalopram, fluoxetine, sertraline),
  • tramadol,
  • tamoxifen,
  • 5-fluorouracil and its derivatives,
  • sulfonylureas (such as tolbutamide and chlorpropamide),
  • ethacrynic acid

Drugs affecting haemostasis may increase the anticoagulant effect of acenocoumarol and increase the risk of haemorrhage:

  • heparin (including low molecular weight heparins),
  • drugs that inhibit platelet aggregation (e.g. dipyridamole, clopidogrel),
  • salicylic acid and its derivatives, acetylsalicylic acid,
  • para-aminosalicylic acid,
  • diflunisal, phenylbutazone or other pyrazolone derivatives (e.g. sulfinpyrazone) and other non-steroidal anti-inflammatory drugs (including selective COX-2 inhibitors),
  • injection of high doses of methylprednisolone.

The anticoagulant effect of acenocoumarol weakens:

  • aminoglutethimide,
  • anticancer drugs (azathioprine, 6-mercaptopurine),
  • barbiturates (phenobarbital),
  • carbamazepine,
  • cholestyramine
  • griseofulvin,
  • oral contraceptives,
  • rifampicin,
  • thiazide-type diuretics,
  • plant products containing St. John's wort (Hypericum perforatum)

Side effects of acenocoumarol

The most serious complication of acenocoumarol use is the occurrence of haemorrhage. These may be obvious and visible bleeding such as bleeding from the gums, nosebleeds, bruising.

You may also have more heavy periods than usual, bleeding from the urinary tract, tarry stools or bloody stools (gastrointestinal bleeding), bloody vomiting, bleeding into the skin, brain or eyes.

Other side effects such as vomiting, nausea or allergic reactions are rare.

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