Reviewed on 10/27/2022

What Is Emicizumab and How Does It Work?

Emicizumab is a prescription medication and it’s a bispecific factor IXa- and factor X-directed antibody indicated for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adult and pediatric patients with hemophilia A (congenital factor VIII deficiency) with or without factor VIII inhibitors.

  • Emicizumab is available under the following different brand names: Hemlibra, emicizumab-kxwh

What Are Side Effects Associated with Using Emicizumab?

Common side effects of Emicizumab include:

  • Injection site reactions,
  • Headache,
  • Joint pain,
  • Fever,
  • Headache,
  • Diarrhea, and
  • Muscle pain

Serious side effects of Emicizumab include:

  • Hives,
  • Difficulty breathing,
  • Swelling of the face, lips, tongue, or throat,
  • Headache,
  • Weakness,
  • Confusion,
  • Lightheadedness,
  • Unusually sick,
  • Back pain,
  • Little or no urination,
  • Stomach pain,
  • Vomiting,
  • Chest pain,
  • Shortness of breath,
  • Coughing up blood,
  • Swelling or redness in the arms or legs,
  • Eye pain or swelling,
  • Vision problems,
  • Numbness in your face, and
  • Yellowing of your skin or eyes (jaundice)

Rare side effects of Emicizumab include:

  • none 

Seek medical care or call 911 at once if you have the following serious side effects:

  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out.

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Are the Dosages of Emicizumab?

Adult and pediatric dosage

Injection, IV solution (single-dose vials)

  • 30 mg /mL
  • 60 mg / 0.4 mL
  • 105 mg / 0.7 mL
  • 150 mg /mL

Hemophilia A

Adult and pediatric dosage

  • Loading dose: 3 mg/kg Subcutaneous every week for the first 4 weeks
  • Maintenance dose
    • 1.5 mg/kg Subcutaneous every week, OR
    • 3 mg/kg Subcutaneous every 2 weeks, OR
    • 6 mg/kg Subcutaneous every 4 weeks
    • Discontinue prophylactic use of bypassing agents 1 day before starting prophylaxis
    • Prophylactic use of factor VIII (FVIII) products may be continued during the first week of prophylaxis

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”

What Other Drugs Interact with Emicizumab?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

  • Emicizumab has severe interactions with no other drugs.
  • Emicizumab has serious interactions with the following drugs:
    • axicabtagene ciloleucel
    • brexucabtagene autoleucel
    • ciltacabtagene autoleucel
    • idecabtagene vicleucel
    • lisocabtagene maraleucel
    • tisagenlecleucel
  • Emicizumab has moderate interactions with the following drugs:
  • Emicizumab has severe interactions with no other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, or if you have health questions or concerns.

What Are Warnings and Precautions for Emicizumab?


  • None

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Emicizumab?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Emicizumab?”


  • Cases of TMA reported from clinical trials; improvement was seen within 1 week following discontinuation of aPCC (see Black Box Warnings)
  • Thrombotic events were reported from clinical trials when on average a cumulative amount of above 100 U/kg/24 hours of IPCC was administered for above 24 hours to patients receiving emicizumab-kxwh prophylaxis; no thrombotic event required anticoagulation therapy; evidence of improvement or resolution saw within one month following discontinuation of aPCC; consider benefits and risks of emicizumab-kxwh if aPCC must be used in patients receiving the drug or resuming prophylaxis following complete resolution of the thrombotic event; monitor for development of thromboembolism when administering aPCC (see Black Box Warnings)
  • Immunogenicity
    • May induce anti-drug antibodies
    • Most patients with anti-emicizumab-kxwh antibodies did not experience a change in plasma concentrations or an increase in bleeding events; in uncommon cases, the presence of neutralizing antibodies with decreasing plasma concentration may be associated with loss of efficacy
    • Monitor for clinical signs of loss of efficacy (. g, increase in breakthrough bleeding events), and if observed, promptly assess the etiology, and consider a change in treatment if neutralizing antibodies are suspected
  • Drug interactions overview
    • Clinical experience suggests that a drug interaction exists with emicizumab-kxwh and aPCC; due to the long half-life of the drug, the potential for interaction with a PCC may persist for up to 6 months after the last dose; possible for hypercoagulability with recombinant factor VIIa (rFVIIa) or Factor VIII (FVIII) with emicizumab-kxwh based on preclinical experiments
  • Drug laboratory test interactions
    • Intrinsic pathway clotting-based laboratory tests were affected; therefore, these laboratory tests should not be used in monitoring emicizumab-kxwh; due to the long half-life of the drug, effects on coagulation essays may persist for up to 6 months after the last dose
    • Results affected by emicizumab: Activated aPTT; Bethesda assays (clotting-based) for FVIII inhibitor titers; one-stage, aPTT-based, single-factor assays; aPTT-based activated protein C resistance (APC-R); and activated clotting time
    • Results unaffected by emicizumab: Bethesda assays (bovine chromogenic) for FVIII inhibitor titers; thrombin time; one-stage, prothrombin time-based, single-factor assays; chromogenic-based single-factor assays other than FVIII; immuno-based assays (. g, ELISA, turbidimetric methods); and genetic tests of coagulation factors (. g, factor V Leiden, prothrombin 20210)

Pregnancy and Lactation

  • No data are available regarding the use in pregnant women to inform a drug-associated risk of major birth defects and miscarriage
  • Unknown whether treatment can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity
  • Should be used during pregnancy only if the potential benefit for the mother outweighs the risk to the fetus
  • Women of childbearing potential should use contraception during treatment
  • Lactation
    • No information is available regarding the presence of emicizumab-kxwh in human milk, the effects on the breastfed child, or the effects on milk production
    • Human IgG is known to be present in human milk

Health Solutions From Our Sponsors