What is the protocol for Hepamerz (Hepatitis B Immunoglobulin) infusion in a patient exposed to Hepatitis B?

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Last updated: January 29, 2026View editorial policy

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Hepamerz Infusion Protocol

Critical Clarification

Hepamerz is L-ornithine L-aspartate (LOLA), used for hepatic encephalopathy treatment, NOT hepatitis B immunoglobulin (HBIG). The evidence provided addresses hepatitis B post-exposure prophylaxis with HBIG, which appears to be a mismatch with your query about "Hepamerz."


If You Are Asking About HBIG (Hepatitis B Immunoglobulin) Post-Exposure Protocol:

Immediate Administration for HBsAg-Positive Exposure

For unvaccinated or incompletely vaccinated persons exposed to HBsAg-positive blood, administer HBIG 0.06 mL/kg intramuscularly as soon as possible (preferably within 24 hours) along with hepatitis B vaccine at a separate anatomic site. 1, 2

Dosing by Clinical Scenario

Percutaneous/Mucosal Exposure to HBsAg-Positive Source:

  • Unvaccinated persons: HBIG 0.06 mL/kg IM immediately + initiate HepB vaccine series 1, 2
  • Vaccinated persons with inadequate antibody (<10 mIU/mL): HBIG 0.06 mL/kg IM immediately + HepB vaccine booster dose 1, 2
  • Vaccinated persons with documented immunity (anti-HBs ≥10 mIU/mL): No HBIG or additional vaccination needed 3

Timing Window:

  • Optimal: Within 24 hours of exposure 1, 3, 2
  • Acceptable: Up to 7 days for percutaneous exposure 1, 3
  • Maximum for sexual exposure: Up to 14 days 1
  • Effectiveness decreases markedly beyond these timeframes 3, 2

Perinatal Exposure (Infants Born to HBsAg-Positive Mothers):

  • HBIG 0.5 mL IM within 12 hours of birth (preferably), efficacy decreases markedly if delayed beyond 48 hours 2
  • Administer HepB vaccine (0.5 mL, 10 μg) within 7 days at separate site 2
  • Complete vaccine series at 1 and 6 months 2

Sexual Exposure to HBsAg-Positive Person:

  • HBIG 0.06 mL/kg IM as single dose within 14 days of last sexual contact 2
  • Initiate HepB vaccine series simultaneously at separate site 2

Administration Technique

  • Route: Intramuscular only; never administer intravenously 2
  • Site: Separate anatomic site from vaccine (e.g., different limbs) 1, 3
  • Inspection: Visually inspect for particulate matter and discoloration before administration 2
  • Aspiration: Aspirate prior to injection to confirm needle is not in vein or artery 2

Special Considerations for Unknown Immunity Status

When a healthcare worker with unknown anti-HBs status has high-risk exposure to HBsAg-positive source, administer HBIG immediately without waiting for blood test results, as the risk of delaying treatment outweighs the cost of potentially treating someone already immune 3

  • Draw blood for baseline anti-HBs testing at time of exposure, but do not delay treatment 3
  • If HBIG is given, delay postvaccination testing for anti-HBs until 4-6 months after HBIG administration to avoid detecting passively acquired antibodies 3

Common Pitfalls to Avoid

  • Do not delay HBIG beyond 24 hours when indicated for HBsAg-positive exposure; effectiveness decreases significantly after 7 days 1, 3, 2
  • Do not restart vaccine series if patient already began vaccination; simply complete the series 1
  • Do not administer HBIG intravenously; it must be given intramuscularly 2
  • Do not assume immunity without documented serologic testing showing anti-HBs ≥10 mIU/mL after complete vaccine series 1, 3
  • Do not test for anti-HBs immediately after HBIG; wait 4-6 months to avoid detecting passive antibodies 3

Alternative Regimen for Vaccine Refusal

If the exposed person refuses hepatitis B vaccine, administer a second dose of HBIG 1 month after the first dose 2


If You Are Actually Asking About Hepamerz (L-ornithine L-aspartate):

The evidence provided does not address Hepamerz/LOLA infusion protocols. Please clarify your question, as Hepamerz is typically used for hepatic encephalopathy at doses of 20-40g daily via IV infusion over 2-6 hours, which is an entirely different medication and indication than what the evidence addresses.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Hepatitis B Post-Exposure Prophylaxis Guidelines

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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