Kybernin P 500 IU/10 mL powder and solvent for solution for injection/infusion – antithrombin III in congenital and acquired deficiency

Kybernin P 500 is a medicine containing antithrombin III obtained from human plasma. Antithrombin is a natural blood protein that prevents excessive clotting, and the medicine belongs to the group of anticoagulants (heparin group, B01AB02).

It is supplied as a powder and solvent for solution for injection/infusion (500 IU in 10 mL, about 50 IU/mL after reconstitution) and is given slowly into a vein, only in hospital, to people with congenital or acquired antithrombin III deficiency.

What is Kybernin P 500 used for and how is it given?

Key facts about the medicine

What is Kybernin P 500 used for?

According to the leaflet, the medicine is used for the prevention and treatment of thromboembolic complications (problems related to blood clotting) in:

• congenital antithrombin III deficiency;
• acquired antithrombin III deficiency.

How is Kybernin P 500 given and dosed?

• The doctor determines the dose and duration of treatment based on the clinical situation and the laboratory-measured antithrombin activity in plasma.
• According to the SmPC, 1 IU of antithrombin per kg body weight raises antithrombin activity by about 1.5%; the initial dose is calculated as: body weight (kg) × (100 – current antithrombin activity in %) × 2/3.
• The usual initial dose in congenital deficiency is 30–50 IU/kg; further doses and frequency are adjusted to laboratory results and the clinical course.
• Antithrombin activity should be kept above 80% during treatment unless the clinical situation requires otherwise; it is measured at least twice daily until stable and then once daily before the next infusion.
• The reconstituted medicine is given slowly intravenously, as an injection or infusion, at no more than 4 mL per minute. It must not be mixed with other medicines; dopamine, dobutamine and furosemide must not be given through the same venous access.

Special patient groups

• Children: no dosing data are available; the medicine must not be used to treat respiratory distress syndrome in premature babies (increased risk of brain bleeding and death without proven benefit).
• Elderly patients, kidney or liver impairment: the leaflet gives no specific recommendations – the dose is always determined individually based on laboratory results.

Contraindications – when the medicine must not be used

• allergy (hypersensitivity) to antithrombin III from human plasma or to any of the excipients.

Warnings and precautions

• allergic hypersensitivity reactions and anaphylactic shock are possible – the patient is closely monitored during the infusion;
• the medicine is made from human plasma; the measures taken are considered effective against HIV, hepatitis B and C, hepatitis A and parvovirus B19, but transmission of infection cannot be totally excluded;
• with regular or repeated use the doctor may recommend vaccination against hepatitis A and B;
• the name and batch number of the medicine are recorded at every administration;
• one vial contains up to 44.76 mg sodium (about 2% of the recommended maximum daily intake for adults).

Interactions with other medicines, food and drink

• heparin – the effect of antithrombin is greatly enhanced by heparin and the risk of bleeding increases; regular coagulation tests (aPTT, anti-Xa activity where appropriate) and daily antithrombin measurement are needed;
• hydroxyethyl starch (HES) is not recommended for preparing the infusion solution because it reduces antithrombin activity;
• tell your doctor about all medicines you take, especially anticoagulants.

Pregnancy and breast-feeding

• Experience in pregnancy is limited; safety in pregnancy and breast-feeding has not been confirmed in controlled studies, but there are no negative experiences. In this period the medicine is used only if clearly indicated, taking into account the increased risk of thromboembolism.

Driving and using machines

• No effect on the ability to drive and use machines has been observed.

Possible side effects

• Rare (up to 1 in 1,000 patients): hypersensitivity reactions including anaphylaxis and shock – skin redness, rash, hives, fall in blood pressure, fast heartbeat, chills, difficulty breathing, chest tightness, nausea, vomiting, restlessness;
• Rare: raised body temperature;
• according to the SmPC, allergic reactions may also include angioedema, burning at the infusion site, headache, lethargy and tingling.

Overdose, missed dose and stopping treatment

• Overdose: no cases of antithrombin overdose have been reported.
• Missed dose and stopping treatment: the medicine is given by healthcare staff; the doctor decides on the schedule and duration based on test results.

Related information

Kybernin P 500 is a hospital medicine used under specialist supervision. For questions about the treatment of antithrombin deficiency, contact your doctor; always read the package leaflet supplied with the medicine.

Composition, pack and manufacturer

• Active substance: human antithrombin III concentrate – 500 IU per vial; specific activity about 5 IU/mg protein.
• Excipients: glycine; sodium chloride; sodium citrate; hydrochloric acid or sodium hydroxide (for pH adjustment); water for injections (solvent).
• Appearance: white powder and clear, colourless solvent; the solution is clear to slightly opalescent.
• Pack: glass vial of powder, glass vial with 10 mL water for injections and a Transofix transfer device.
• Marketing authorisation holder: PharmaSwiss d.o.o., Batajnički drum 5A, Belgrade. Manufacturer: CSL Behring GmbH, Emil-von-Behring-Straße 76, Marburg, Germany.
• Authorisation number: 000456234 2023 of 23.04.2024 (renewal).

Storage

• Store below 25 °C; do not freeze; keep the vial in the outer carton to protect from light. Shelf life: 3 years.
• After reconstitution chemical and physical stability has been shown for 8 hours at up to 25 °C, but because it contains no preservative the solution is used immediately.
• Do not use cloudy solutions or solutions with particles. Keep out of the sight and reach of children.

Frequently asked questions

What is antithrombin III and why is it replaced?

Antithrombin is a natural blood protein that prevents clot formation. In congenital or acquired deficiency the risk of thrombosis rises, so Kybernin P 500 is given to prevent and treat thromboembolic complications.

How does the doctor determine the dose?

Based on body weight and the measured antithrombin activity in the blood; according to the SmPC the aim is to keep activity above 80% during treatment, with values checked several times a day until stable.

Why is caution needed with heparin?

Heparin greatly enhances the effect of antithrombin, so the risk of bleeding increases. With concomitant use, coagulation parameters and antithrombin levels are checked regularly.

Can Kybernin P 500 transmit an infection?

The medicine is made from human plasma with donor selection, testing and virus inactivation steps. These measures are effective against HIV and hepatitis B, C and A, but the possibility of transmitting infection cannot be totally excluded.

Sources

• ALIMS – Kybernin P 500 patient leaflet (PIL)
• ALIMS – Kybernin P 500 summary of product characteristics (SmPC)

Date sources were checked: 25.10.2026.