Template:Crofab dosing: Difference between revisions

 
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*Administer antivenom as soon as possible if the indications are met and antivenom is available.<ref>Dart RC et al. Efficacy of post envenomation administration of antivenin. Toxicon. 1988;26:1218–1221.</ref>
*Administration should slow swelling  and decrease pain
===Initial Administration===
===Initial Administration===
*The dosing of CroFab is the same for adults and children
*Initial dose: 6 vials<ref>Gerardo CJ. The efficacy of crotalidea polyvalent immune fab (ovine) antivenom versus placebo plus optional rescue therapy on recovery from copperhead snake envenomation: A randomized, double-blind, placebo-controlled, clinical trial. Annals of EM. August 2017. 70(2):233-244.</ref>
*Establish initial control of envenomation by giving 4-6 vials
*Typically diluted into 250 cc or 1 L of normal saline and infused over an hour
*Control achieved? (Cessation of progression of all components of envenomation, including labs checked 2 hours after infusion started)
*Same dose for both adults and pediatrics (may have to adjust the dilution of CroFab for small children so that they are not volume overloaded)
**'''If yes: '''then perform serial exams and consider maintenance therapy
**'''If no:''' repeat infusion of 4-6 vials and then re-evaluate for control


===Maintenance therapy===
===Maintenance therapy===
*''Maintance therapy may be indicated after initial dosing based on local protocols even if control is achieved.<ref>Crofab treatment agorithmn http://www.crofab.com/documents/CroFab-Treatment_Algorithm.pdf</ref>
*May repeat dose (2 vials) at 6, 12, and 18 hours later if symptoms not controlled<ref>Gerardo CJ. The efficacy of crotalidea polyvalent immune fab (ovine) antivenom versus placebo plus optional rescue therapy on recovery from copperhead snake envenomation: A randomized, double-blind, placebo-controlled, clinical trial. Annals of EM. August 2017. 70(2):233-244.</ref>
**Infuse 2-vial doses at 6, 12, and 18hr after initial control achieved
**''Maintance therapy may be indicated after initial dosing based on local protocols even if control is achieved.<ref>Crofab treatment agorithmn http://www.crofab.com/documents/CroFab-Treatment_Algorithm.pdf</ref>


===Envenomation control measurement===
===Envenomation control measurement===
*Must observe for progression of envenomation during and after antivenom infusion
*Observe for progression of envenomation during and after antivenom infusion
*Measure limb circumference at several site above and below bite
*Measure limb circumference at several sites above and below bite
*Mark advancing border of edema q30min
*Mark advancing border of edema q30min
*Repeat labs q4hr or after each course of antivenom (whichever is more frequent)
*Repeat labs q4hr or after each course of antivenom (whichever is more frequent)
===Antivenom Side Effects===
 
*Acute reactions occur in <10% pts
===Side Effects===
**If occurs stop infusion and give antihistamines / epi if needed
*Acute [[allergic reactions]] occur in <10% pts
**If occurs stop infusion and give epinephrine/antihistamines if needed
*Recurrent [[thrombocytopenia]] has been described up to 2 weeks after transfusion with FabAV and is likely a result of isolated renal clearance of FabAV and persistent presence of actual venom in serum.<ref>Ruha AM et al. Late hematologic toxicity following treatment of rattlesnake envenomation with crotalidae polyvalent immune Fab antivenom. Toxicon. 2011;57:53–59.</ref>
*Recurrent [[thrombocytopenia]] has been described up to 2 weeks after transfusion with FabAV and is likely a result of isolated renal clearance of FabAV and persistent presence of actual venom in serum.<ref>Ruha AM et al. Late hematologic toxicity following treatment of rattlesnake envenomation with crotalidae polyvalent immune Fab antivenom. Toxicon. 2011;57:53–59.</ref>
**Only described in patients with history of thrombocytopenia during hospital course
**Warrants close monitoring of platelets by primary physician or return visit after discharge
**Warrants close monitoring of platelets by primary physician or return visit after discharge
*[[Serum sickness]] is unlikely but precautions should be given to patents upon discharge

Latest revision as of 17:26, 28 September 2019

Initial Administration

  • Initial dose: 6 vials[1]
  • Typically diluted into 250 cc or 1 L of normal saline and infused over an hour
  • Same dose for both adults and pediatrics (may have to adjust the dilution of CroFab for small children so that they are not volume overloaded)

Maintenance therapy

  • May repeat dose (2 vials) at 6, 12, and 18 hours later if symptoms not controlled[2]
    • Maintance therapy may be indicated after initial dosing based on local protocols even if control is achieved.[3]

Envenomation control measurement

  • Observe for progression of envenomation during and after antivenom infusion
  • Measure limb circumference at several sites above and below bite
  • Mark advancing border of edema q30min
  • Repeat labs q4hr or after each course of antivenom (whichever is more frequent)

Side Effects

  • Acute allergic reactions occur in <10% pts
    • If occurs stop infusion and give epinephrine/antihistamines if needed
  • Recurrent thrombocytopenia has been described up to 2 weeks after transfusion with FabAV and is likely a result of isolated renal clearance of FabAV and persistent presence of actual venom in serum.[4]
    • Warrants close monitoring of platelets by primary physician or return visit after discharge
  • Serum sickness is unlikely but precautions should be given to patents upon discharge
  1. Gerardo CJ. The efficacy of crotalidea polyvalent immune fab (ovine) antivenom versus placebo plus optional rescue therapy on recovery from copperhead snake envenomation: A randomized, double-blind, placebo-controlled, clinical trial. Annals of EM. August 2017. 70(2):233-244.
  2. Gerardo CJ. The efficacy of crotalidea polyvalent immune fab (ovine) antivenom versus placebo plus optional rescue therapy on recovery from copperhead snake envenomation: A randomized, double-blind, placebo-controlled, clinical trial. Annals of EM. August 2017. 70(2):233-244.
  3. Crofab treatment agorithmn http://www.crofab.com/documents/CroFab-Treatment_Algorithm.pdf
  4. Ruha AM et al. Late hematologic toxicity following treatment of rattlesnake envenomation with crotalidae polyvalent immune Fab antivenom. Toxicon. 2011;57:53–59.