At a glance

What is bivalirudin?

Bivalirudin is a synthetic peptide of 20 amino acids that works as an anticoagulant, or blood thinner. It belongs to a class called direct thrombin inhibitors¹, meaning it blocks thrombin, the enzyme that drives the final step of clot formation, by binding to it directly. It is made by chemical synthesis and sold under the brand name Angiomax (and as Angiox outside the United States).

It is given only by intravenous infusion in a hospital, typically in a cardiac catheterization lab, and is not an oral or at-home medication.

The history of bivalirudin

Bivalirudin traces back to the leech. The medicinal leech makes a natural anticoagulant protein called hirudin², which is why a leech can feed without the blood clotting, and hirudin became the template for a family of direct thrombin inhibitors. Bivalirudin is a short synthetic analog built from that model, engineered to bind thrombin at two sites at once, which makes it a bivalent inhibitor.

It was developed as a more predictable, shorter-acting alternative to heparin for use during heart procedures, and the FDA approved it in 2000. Unlike the leech protein it was modeled on, its effect is reversible and brief, which suited the controlled setting of angioplasty.

How does bivalirudin work?

Bivalirudin works by directly binding and blocking thrombin, the enzyme at the center of blood clotting. Thrombin converts fibrinogen into the fibrin mesh that holds a clot together and also activates platelets, and by occupying thrombin, bivalirudin stops both. It is a bivalent inhibitor¹: one end binds thrombin's active (catalytic) site, and the other binds a separate docking region, called exosite 1, that normally grips fibrinogen. Because it latches on at two points, it blocks thrombin that is free in the blood as well as thrombin already bound inside a clot, which heparin does less well.

Its action is also reversible and short-lived. Thrombin slowly cleaves the bound drug and recovers its function, so the effect fades within roughly 25 minutes¹ of stopping the infusion, which makes it predictable to use during a procedure.

In the HORIZONS-AMI trial³ of 3,602 heart-attack patients undergoing angioplasty, bivalirudin alone reduced 30-day major bleeding and lowered death from cardiac causes compared with heparin plus a glycoprotein IIb/IIIa inhibitor.

Is it FDA-approved?

Yes. The FDA approved¹ bivalirudin (Angiomax) in 2000 as an anticoagulant for use during coronary angioplasty, and its labeling later covered patients with or at risk of heparin-induced thrombocytopenia undergoing PCI. It is an established, guideline-recognized option for anticoagulation during these procedures.

What is bivalirudin prescribed for?

Bivalirudin is used as the anticoagulant during percutaneous coronary intervention (PCI), the catheter-based procedures (angioplasty and stent placement) that open blocked heart arteries. It is given to prevent clots from forming on the catheter and the freshly treated artery during the procedure. It is especially valuable for patients with heparin-induced thrombocytopenia¹ (HIT), a serious immune reaction to heparin, because it provides anticoagulation without using heparin at all. It is administered and monitored by the medical team, not self-administered.

What are the side effects?

The main risk of bivalirudin, as with any anticoagulant, is bleeding, though in trials it caused less major bleeding than heparin-based regimens. Other effects reported during treatment include:

• Back pain
• Nausea
• Low blood pressure
• Headache

One specific signal from the HORIZONS-AMI trial³ was a higher rate of acute stent thrombosis, a clot forming on the new stent, in the first 24 hours; this did not persist at 30 days and is managed by ensuring adequate antiplatelet therapy. Because it is used only in monitored hospital settings, its dosing is carefully controlled.

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