CroFab ® Treatment Algorithm

Assess Patient

Mark leading edge of swelling and tenderness every 15-30 minutes

Immobilize and elevate extremity

Treat pain (IV opioids preferred)

Obtain initial lab studies (protime, Hgb, platelets, fibrinogen)

Update tetanus vaccine

Contact poison control center (1-800-222-1222)

Have you assessed the patient?


Check for Signs of Envenomation

Swelling, tenderness, redness, ecchymosis, or blebs at the bite site

Elevated protime; decreased fibrinogen or platelets

Systemic signs, such as hypotension, bleeding beyond the puncture site, refractory vomiting, diarrhea, angioedema, neurotoxicity

Are there signs of envenomation?

Apparent Dry Bite/No Bite

Do not administer CroFab ®

Observe patient for ≥ 8 hours

Repeat labs prior to discharge

Check patient for signs of envenomation

Has the patient presented any new symptoms?

Check for Progression of Clinical Effects

Swelling that is more than minimal and that is progressing

Elevated protime; decreased fibrinogen or platelets

Any systemic signs

Are there signs of progression?

Apparent Minor Envenomation

Do not administer CroFab ®

Observe patient for 12-24 hours

Repeat labs at 4-6 hours and prior to discharge

Check patient for progression or any signs of envenomation

Have the patient’s symptoms progressed?

Administer CroFab ®

Establish IV access and give IV fluids

Pediatric CroFab ® dose = adult CroFab ® dose

Mix 4-12 vials of CroFab ® in 250 mL normal saline and infuse IV over 1 hour

  • The starting dose may vary from a minimum of 4 vials to a maximum of 12 vials based on clinical judgment and severity of envenomation
  • For patients in shock or with serious active bleeding, increase initial dose of antivenom to 8-12 vials and call for expert assistance

Initiate first dose of CroFab ® in ED or ICU

Re-examine patient for treatment response within 1 hour of completion of CroFab ® infusion

Have you administered CroFab ®?


Determine if Initial Control of Envenomation Has Been Achieved

Swelling and tenderness not progressing

Protime, fibrinogen, and platelets normal or clearly improving

Clinically stable (not hypotensive, etc)

Neurotoxicity resolved or clearly improving

Has initial control of envenomation been achieved?

Repeat CroFab ® Until Initial Control Is Achieved

If initial control is not achieved after 2 doses of CroFab ®, call for expert assistance

Have you already given the patient 2 doses of CroFab ®?

Monitor Patient

Perform serial examinations

Observe patient 18-24 hours after initial control for progression of any venom effect

Follow-up labs 6-12 hours after initial control and prior to discharge

If patient develops new or worsening signs of envenomation, administer additional doses of CroFab ®

Is the patient developing new or worsening signs of envenomation?

Determine if Patient Meets Discharge Criteria

No progression of any venom effect during the specified observation period

No unfavorable laboratory trends in protime, fibrinogen, or platelets

Does the patient meet discharge criteria?