Known brand names include Lovenox.
A low molecular weight heparin injected under the skin, usually once or twice a day. It prevents blood clots after surgery or during immobilizing illness, treats DVT with or without PE, and is used in unstable angina and heart attack.
Enoxaparin is a low molecular weight heparin, a form of the blood thinner heparin made of smaller pieces. It mostly blocks factor Xa, a clotting protein, and acts much less on thrombin (factor IIa) than standard heparin does. With these clotting proteins held back, the body forms clots more slowly.
Its effect peaks 3 to 5 hours after a shot under the skin, and nearly all of the injected dose reaches the blood. The liver breaks down most of it and the kidneys remove the rest, so it builds up and raises bleeding risk in people with weak kidneys. Because it slows clotting, bleeding is its main risk, including bleeding around the spine after spinal or epidural anesthesia that can cause lasting paralysis. Protamine, given into a vein, can largely reverse it after an overdose.
Enoxaparin is a blood thinner that prevents and treats deep vein thrombosis, a blood clot in a vein, usually in the leg. These clots can lead to a clot in the lungs, called a pulmonary embolism. It is used to prevent these clots after abdominal surgery or hip or knee replacement, and in people who are very ill and cannot move around much. It also helps prevent heart damage, another heart attack, or death in people having a heart attack or a type of severe chest pain called unstable angina.
It comes in prefilled syringes and vials for shots under the skin, and people can be taught to give it to themselves. Leg clots with a lung clot are treated in the hospital, while leg clots without one can be treated at home, in both cases alongside warfarin. For heart attacks and unstable angina, it is given together with aspirin. It is not approved for babies, and its safety and benefit in children have not been shown.
Bleeding, bruising, low blood counts, and pain, bruising, or lumps where it is injected are the common side effects. Nausea, diarrhea, fever, swelling, confusion, and changes in liver tests can also happen. The label treats bleeding around the spine that can cause paralysis as the most serious risk, along with major bleeding, a drop in platelets including an immune reaction to heparin, high potassium, skin damage, serious allergic reactions, and bone thinning with long-term use.
This is the boxed warning, the warning the FDA label prints first.
Spinal or epidural hematomas. Patients on LMWH who receive neuraxial anesthesia or a spinal puncture can develop hematomas that cause long-term or permanent paralysis. Risk rises with indwelling epidural catheters, NSAIDs, platelet inhibitors or other anticoagulants, traumatic or repeated punctures, and prior spinal deformity or surgery. Monitor neurologic status often and treat compromise urgently.
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