Arixtra

"Arixtra" (fondaparinux sodium) is a drug belonging to the class of anticoagulants, specifically low molecular weight heparins. It is used to prevent and treat thromboembolic complications in patients with various diseases such as deep venous thrombosis, pulmonary embolism, myocardial infarction and other conditions associated with thrombosis and thromboembolism.

Fondaparinux sodium works by preventing the formation of thrombi (blood clots) by inhibiting the activity of factor Xa, which is a key enzyme in the blood clotting process. This reduces the tendency of the blood to form blood clots and helps prevent thrombosis and its complications.

The drug is usually administered by subcutaneous injection and is available in various dosages to adapt to the individual needs of the patient. It is typically used in hospitals or under medical supervision in an outpatient setting.

Indications Arikstri

• Prevention and treatment of deep venous thrombosis (DVT) and pulmonary embolism (PE) in patients at high risk of developing thromboembolic complications. This may include patients with acute myocardial infarction, patients following pelvic surgery or traumatic injury, and patients with acute medical conditions who have limited mobility.
• Prevention and treatment of thrombosis during pregnancy and the postpartum period in women with a high risk of thromboembolic complications or a history of previous thrombosis.
• Prophylaxis of thrombosis in patients with atrial fibrillation and other arrhythmias who are at high risk of thromboembolic complications and require anticoagulant therapy.
• Treatment and prevention of thrombosis in patients with arterial or venous catheters.

Release form

Injection solution: The drug is supplied in glass ampoules or pen syringes for subcutaneous administration. This is the most common method of using Arixtra, as it ensures fast and reliable administration of the drug.

Pharmacodynamics

Its pharmacodynamics are based on its ability to inhibit the activity of factor Xa, which is a key enzyme in the blood clotting process.

The drug binds to antithrombin III, increasing its activity, which leads to increased inhibition of factor Xa. This in turn reduces the conversion of prothrombin to thrombin, which reduces the formation of blood clots and prevents the further development of thromboembolic complications.

Thus, "Arixtra" exhibits an antithrombotic effect, reducing the tendency of the blood to form blood clots and preventing their development in various vascular systems. This makes it an effective tool for the prevention and treatment of thromboembolic complications in patients with various diseases.

Pharmacokinetics

• Absorption: Since Arixtra is usually administered intramuscularly or subcutaneously, it is absorbed fairly quickly. Peak plasma concentrations are usually reached within a few hours after administration.
• Distribution: The drug has a high volume of distribution, meaning that it is rapidly distributed throughout the body after absorption. Fondaparinux sodium is somewhat less bound to plasma proteins.
• Metabolism: Fondaparinux sodium is not metabolized in the liver, so there is no need for regular monitoring of liver function in patients.
• Excretion: The drug is excreted mainly unchanged by the kidneys. Its elimination half-life in the body is about 4-6 hours.

Dosing and administration

• Prevention of thrombosis in surgical patients: It is usually recommended to administer 2.5 mg of Arixtra once daily.
• Prophylaxis of thrombosis in patients at high risk of thromboembolic complications: The dosage may be increased to 5 mg once daily, depending on the clinical situation.
• Treatment of thrombosis and embolism: Usually it is recommended to start with 5 mg of "Arixtra" subcutaneously twice a day. For patients weighing more than 90 kg, an increase in the dose may be recommended.
• Prevention of thrombosis in pregnancy: The dosage may vary depending on the individual characteristics and clinical situation, and should be determined by the doctor.

Use Arikstri during pregnancy

• Use for hypersensitivity to heparin:

  • Fondaparinux is used as a safe alternative to heparin for hypersensitivity or heparin-induced thrombocytopenia in pregnancy. In one case, fondaparinux was successfully used to treat a pregnant woman with protein S deficiency and previous deep vein thrombosis who had developed hypersensitivity to heparin (Mazzolai et al., 2006).

• Literature review:

  • A review of the literature on the use of fondaparinux in pregnant women examined 65 cases. The drug was well tolerated, and the incidence of pregnancy complications was similar to that observed in the general population. However, additional studies are needed to assess the safety of the drug in relation to congenital malformations (De Carolis et al., 2015).

• Use for heparin-induced thrombocytopenia (HIT):

  • In one case, fondaparinux was used successfully to treat a pregnant woman with acute pulmonary thromboembolism and HIT in late pregnancy. The drug showed good results without complications for the mother and fetus (Ciurzyński et al., 2011).

• Pharmacokinetics and absence of placental transfer:

  • In vitro studies have shown the absence of placental transfer of fondaparinux, which reduces the risk of exposure to the fetus (Lagrange et al., 2002).

• General user experience:

  • In a retrospective study of 120 pregnant women treated with fondaparinux for VTE prophylaxis, the drug was found to be well tolerated and effective. Complications included hemorrhage (5 cases), miscarriages (2 cases), and preterm birth (2 cases) (Dempfle et al., 2021).

Contraindications

• Hypersensitivity: In patients with known hypersensitivity to fondaparin, sodium, other low molecular weight heparins or any other component of Arixtra, the use of the drug is contraindicated.
• Severe bleeding: The drug should be used with caution in patients with active bleeding or an increased risk of developing it. In the presence of severe bleeding, the use of Arixtra is contraindicated.
• Thrombocytopenia: In patients with thrombocytopenia (low platelet count in the blood) or other bleeding disorders, the drug should be used with caution.
• Unstable patient condition: The drug should be used with caution in patients with an unstable condition that may lead to severe bleeding or other serious complications.
• Active gastric and intestinal ulcers: The use of Arixtra may increase the risk of bleeding in patients with active gastrointestinal ulcers.
• Epidural or spinal anesthesia: The drug should be used with caution in patients who are planning or undergoing epidural or spinal anesthesia, as this may increase the risk of developing a spinal or epidural hematoma and subsequent compression injury to the spinal cord.

Side effects Arikstri

• Bleeding: This is the most serious side effect of anticoagulants, including low molecular weight heparins. Bleeding of various locations may occur: internal (for example, intestinal or hemorrhagic stroke), intracranial, from the nose, hematomas on the skin, etc.
• Thrombocytopenia: Some patients may develop thrombocytopenia (low platelet count in the blood), which can lead to an increased risk of thrombosis.
• Heparin-induced thrombocytopenia (HIT): This is a serious complication that can lead to thrombosis and thromboembolic complications.
• Allergic reactions: Include allergic skin rashes, itching, hives and, in rare cases, anaphylaxis.
• Spotted bleeding and hematomas: Hematoma or bleeding may develop at injection sites.
• Increased activity of liver enzymes: Some patients may experience a temporary increase in the activity of aminotransferases and other liver enzymes.
• Alopecia: In rare cases, temporary hair loss may occur.
• Increased blood potassium: Hyperkalemia may occur in some patients.

Overdose

An overdose of Arikstroy may lead to an increased risk of bleeding. If you suspect an overdose or bleeding, you should immediately seek medical help.

Treatment of overdose may include the following measures:

1. Stop drug administration.
2. Symptomatic treatment aimed at controlling bleeding.
3. Transfusion of fresh frozen plasma or other blood substitutes to restore circulating blood volume and coagulation.

Interactions with other drugs

• Drugs that enhance the anticoagulant effect: The combination of Arixtra with other anticoagulants such as warfarin, acenocoumarol, dabigatran, rivaroxaban and apixaban may increase the risk of bleeding. These combinations require careful medical monitoring and possible dosage adjustment.
• Drugs that increase the risk of bleeding: Some drugs, such as non-steroidal anti-inflammatory drugs (NSAIDs), aspirin, ticagrelor, clofibrate and others, may increase the risk of bleeding when used simultaneously with Arixtra.
• Drugs that reduce the anticoagulant effect: Some drugs, such as antiepileptic drugs (for example, carbamazepine, phenytoin), rifampicin and other inducers of microsomal liver enzymes, may reduce the effectiveness of Arixtra.
• Drugs that increase the risk of hyperkalemia: Certain drugs, such as potassium-sparing diuretics, angiotensin-converting enzyme inhibitors (ACEIs), some nonsteroidal anti-inflammatory drugs (NSAIDs) and others, may increase the risk of hyperkalemia when used concomitantly with Arixtra.
• Drugs that increase the risk of thrombosis: The use of Arixtra with certain drugs, such as estrogens and hormonal drugs, may increase the risk of thrombosis.

Storage conditions

• Store the drug in the original packaging or in a dark container, protected from light.
• Store Arixtra at a temperature between 15°C and 25°C.
• Avoid freezing the drug.
• Keep the drug out of the reach of children.
• Follow manufacturer's instructions regarding expiration dates after opening the package (if applicable).
• If the drug is stored in the refrigerator, avoid direct contact with the freezer or place where there may be a significant change in temperature.