Acenocoumarol, Phenprocoumon (Efficacy)

Both acenocoumarol and phenprocoumon are two coumarin derivatives oral anticoagulant drugs that antagonize vitamin K.

Acenocoumarol (Sintrom ® brand name) is one of the most widely used oral anticoagulants. It prevents the formation in the liver of the active factors of coagulation II, VII, IX and X and protein C, by inhibiting the gamma carboxylation of precursor proteins mediated by vitamin K, so that acenocoumarol and phenprocoumon are antagonists of vitamin K.

They have a slightly shorter duration of effect than warfarin, which could be an advantage in case of overdose bleeding.


Hypersensitivity to coumarin derivatives.

Contraindicated in pregnancy, lack of cooperation of the patient, hemorrhagic diathesis or haemorrhagic blood dyscrasia, recent or planned surgical interventions in the central nervous system, ophthalmological operations and and traumatic interventions that expose large areas of tissue.

Contraindicated in peptic ulcer or hemorrhages in the gastrointestinal, urogenital or respiratory tract, cerebrovascular hemorrhages, acute pericarditis, pericardial effusions, severe arterial hypertension, hepatic insufficiency or severe renal insufficiency. Drugs contraindicated in patients with hereditary, acquired coagulopathies and thrombocytopenia with platelet counts less than 50x109/L and in situations with increased fibrinolytic activity.


Precautions should be taken when prescribing these drugs to patients with hepatic impairment and/or mild or moderate renal insufficiency, or to patients with severe heart failure.

Precautions in the case of the elderly and children (more frequent control of the coagulation parameters in these cases).

Medical professional should be cautious when prescribing acenocoumarol or phenprocoumon to patients with known or suspected protein C or S deficiency, cautions in patients with thyrotoxicosis.

Extreme precautions in patients with tumors, kidney diseases, infections, inflammations and absorption disorders.

Intramuscular injections should be avoided during treatment (risk of bruising). Caution in surgical and diagnostic procedures.

In high-risk patients stop treatment gradually.


Bleeding in any organ. Calciphylaxis.


The effect of coumarin derivatives is potentiated by: allopurinol, anabolic steroids, androgens, amiodarone, quinidine, erythromycin, tetracyclines, clindamycin, neomycin, chloramphenicol, amoxicillin, cephalosporins (2nd and 3rd generation), fluoroquinolones, ac. clofibric and analogous, disulfiram, ac. ethacrynic, cimetidine, glucagon, paracetamol, citalopram, fluoxetine, sertraline, fluvastatin, atorvastatin, simvastatin, metronidazole, miconazole (even applied locally), sulfonamides (including cotrimoxazole), tolbutamide, chlorpropamide, thyroid hormones, tamoxifen, tramadol, noscapine, prokinetic agents , proton pump inhibitors, antacids, viloxacin and corticosteroids (methylprednisolone, prednisone).

Do not use with substances that modify hemostasis (danger of gastrointestinal bleeding): heparin (except those situations where rapid anticoagulation is required), inhibitors of platelet aggregation (clopidogrel, ticlopidine, AAS and derivatives), phenylbutazone or pyrazolone derivatives, other NSAIDs (non-steroidal anti-inflammatory drugs), inhibitors of cyclo-oxygenase 2, high doses of methylprednisolone IV, urokinase, streptokinase, alteplase, thrombin inhibitors, vitamin E.

The antithrombotic effect may be diminished by aminoglutethimide, barbiturates, carbamazepine, cholestyramine, griseofulvin, oral contraceptives, rifampicin, thiazide diuretics, azathioprine, 6-mercaptopurine, ritonavir, nelfinavir, H. perforatum.

Acenocoumarol/phenprocoumon can raise the serum concentration of hydantoin..

Both drugs can increase the hypoglycaemic effect of sulfonylurea derivatives.

Avoid taking these drugs together with alcohol, currant juice, foods high in vitamin K (spinach, cauliflower, cabbage).


  • Sintrom ® (Acenocumarol)

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