Anticoagulant Therapy


• Any heparin requires a platelet count check twice a week.

• Early relay by vitamin K antagonists (VKA) reduces the risk of thrombocytopenia.

• Thrombocytopenia heparin must be confirmed in vitro (Immuno-Allergy-indicating definitely against heparin, except in exceptional situations).

• Monitoring of VKA based on the assessment of the International Normalized Ratio (INR) and either prothrombin time (PT), which varies depending on the reagents.

• Although the substances interfering with vitamin K antagonists, do not hesitate to check the INR.

• To evaluate the benefit / risk ratio of VKA therapy depending on the terrain.

Low molecular weight heparin (LMWH):

They are obtained by fractionation of heparin and have an anti-Xa activity (antithrombotic) without hémorragipare anticoagulant activity (especially anti-IIa).

They prophylactic and curative indications, according to the dosage or specialty. The risk of thrombocytopenia is less than under unfractionated heparin (UFH).


– Haemorrhagic manifestations, may bleed organic lesion.

– Evolutionary digestive ulcer.

– Hemorrhagic Stroke (CT so prior to any stroke).

– Acute pericarditis.

– Acute endocarditis, except mechanical prosthesis.

– Previous history of thrombocytopenia heparin.

– The caution in case of injury to the membrane of the retina, kidney or liver failure, hypertension not balanced.

Prophylactic use:

Order No. 1: low risk of thromboembolism

LOVENOX [enoxaparin sodium] 2000 IU, or INNOHEP [tinzaparin sodium] 3500 IU, 1 subcutaneous injection daily.

– Platelet count prior ++, then 2 times a week.

Ordinance No. 2: increased thromboembolic risk (cancer, history of thromboembolism)

INNOHEP [tinzaparin sodium] 3500 IU, 1 subcutaneous injection daily.

– Even platelet monitoring.

No.3: thromboembolic risk high

LOVENOX [enoxaparin sodium] or 4,000 IU INNOHEP [tinzaparin sodium] 4500 IU, 1 subcutaneous injection daily.

– Even platelet monitoring.

Curative use in the treatment of deep vein thrombosis:

Order :

– In a single injection per day: FRAXODI [nadroparin calcium] 0.1 ml / 10 kg or INNOHEP [tinzaparin sodium] 175 IU / kg.

– Monitoring of platelet 2 times a week.

– The monitoring of plasma anti-Xa activity may be necessary especially if renal failure, unusual weight, clinical ineffectiveness of treatment, bleeding. This must be between 0.5 and 1 anti-Xa IU / ml. For INNOHEP[tinzaparin sodium] Specifically, the plasma anti-Xa levels should not exceed 1.8 UI antiXa / ml.

– Start as soon as possible to balance the AVK for the INR before the 10th day of heparin +++.

Curative use in the treatment of atrial fibrillation and atrial flutter recently discovered (pending the effectiveness of AVK):

Order :

– It takes TWO injections per day: LOVENOX [enoxaparin sodium] 1 mg / kg twice daily.

– This LMWH has no authorization in this indication, but is the only LMWH used in studies of anticoagulation in atrial arrhythmias.


– Bleeding can exceptionally neutralize treatment PROTAMINE (sulfate or hydrochloride), dose for dose, preferably in multiple injections.

– Hematoma at the injection site: in connection with the purging of the syringe, not necessary.

– Osteoporosis in prolonged treatment over several months.

– Cutaneous necrosis at the injection site: stopping treatment, relays AVK.

– Cholesterol embolism (rare) appearance of a reticular livedo on the legs, painful purple toes without coldness, sometimes kidney failure: stop treatment immediately.

– Thrombocytopenia immunoallergic +++ interrupt heparin from a decrease of 30% of initial digits; immediately check the platelet count for confirmation; if confirmed, immediately relay AVK and antiplatelet (during the necessary time for equilibration of AVK).

– Biological confirmation of immuno-Free is required (laboratories).

Vitamin K antagonists (VKA):

– Action in the liver resulting in decreased factors II, VII, IX and X, and proteins C and S.

– Three specialties used: PREVISCAN, SINTROM and MINISINTROM (equivalent to 1/4 cp SINTROM), coumadin.

– The use of PREVISCAN or coumadin seems preferable: longer half-life, a single daily dose, steady INR relatively fixed dose according to the patient; Counterparty longer persistence of the AVK effect.

– Do not make loading doses.

– The equilibration is rarely reached before ten days of treatment.

– Taking the evening allows immediate correction of the daily dose, depending on the INR done that morning.


– These heparins.

– Plus: pregnancy and lactation, alcoholism, psychological context unfit for a proper understanding and observance.

Interactions (drug, non-drug):

long and non-exhaustive list.

Cons-indications intramuscular injections +++ (subcutaneously possible), intra-articular injections +++.

Need to control the INR for dose adjustment.


– Aspirin, NSAIDs, TICLID (cons-indicated)


– Statins, fibrates,

– Inhibitors of proton pump and cimetidine

– Thyroid hormones,

– Fluconazole, miconazole, ketoconazole,

– Fluvoxamine

– Allopurinol

– Broad-spectrum antibiotics, antibacterial sulfonamides and quinolones.

Decreased effect:

– Gastrointestinal protectants, coal,

– Lubricant laxatives,


– Barbiturates, carbamazepine, phenytoin,

– Rifampicin, griseofulvin,

– Foods rich in vitamin K: cabbage, cereals, broccoli, carrots, vegetables, organ meats.

Treatment initiation:

PREVISCAN 1 tab night.

– Simultaneously pursuing heparin (early overlap between the 2nd and 4th day).

– The overlap lasts at least 4 days.

– Control of the INR 48 hours later and careful dose adjustment (1/4 cp).

– Frequent INR controls in the first weeks, then 1 time per month.

– Stop heparin once the INR target is reached.

Target INR:

– In very elderly in AC / FA, a compromise between the risk of bleeding and thrombotic risk can be achieved by bringing the INR between 2 and 2.5.

– If last generation mechanical prosthesis in the aortic position, in the absence of risk factor for thromboembolism, the INR target is 2 to 3.

anticoagulant therapy


Order :

– Doing a blood test for PT and INR once a month, more if necessary according to medical advice, qs X months

– Do not take any medication without informing the doctor.

Patient Education +++

usefulness of treatment, risk sports and activities against-indicated, interactions with certain treatments for self-medication, wearing a card / treatment diary with postponement of INR and dose control in doubt.

Special case of antithrombotic therapy in atrial fibrillation:

– Atrial fibrillation and atrial flutter have the same potential embolic (indeed, they often alternate in the same patient).

– The paroxysmal and permanent forms also have the same potential embolic

– CHADS2 score stratified the thromboembolic risk of a patient and used to select the antithrombotic treatment most suited.

– However, other elements such as the atrium size G on ultrasound, the existence of a mitral valve, also come into consideration … Leave the specialist decide the most appropriate treatment.

CHADS2 Score: Add the points

Criteria for calculating the score Points

Age> 75 years 1


1 diabetes

heart failure 1

ATCD transient or established stroke

or peripheral embolism 2

Antithrombotic Therapy recommended:

CHAD2 score = 0: aspirin 100-325 mg daily

CHADS2 score = 1: aspirin 100-325 mg daily or vitamin K antagonists

CHADS2 score> 1: anticoagulants

Preparation for electrical cardioversion: anticoagulants (electric shock itself thrombogenic)

Thus, it is not wrong to let a patient 65 who made the paroxysmal atrial fibrillation “on apparently healthy heart” aspirin … And, apart from absolute cons-indications to a patient of 84 years, hypertensive balanced makes paroxysmal atrial fibrillation under AVK …