Crotalidae polyvalent immune FAB (ovine) (CroFab, Copperhead Antivenom (Immune FAB), Cottonmouth Antivenom (Immune FAB), Diamondback Antivenom (Immune FAB), Fab Crotalidae polyval AD, Rattlesnake Antivenom (Immune FAB), Sidewinder Antivenom (Immune FAB), Water Moccasin Antivenom (Immune FAB))

Dosing and uses of CroFab, Copperhead Antivenom (Immune FAB) (Crotalidae polyvalent immune FAB (ovine))

• Adult
• Pediatric

 

Adult dosage forms and strengths

powder for injection

• Up to 1g/vial (ovine antiserum)

 

Envenomation

Indicated for North American crotalid envenomation by Crotalinae rattlesnakes (eg, cottonmouths/water moccasins, copperheads, rattlesnakes)

InitiaL

• Begin treatment as soon as possible (ideally within 6 hr of snakebite) in patients who develop signs of progressive envenomation including worsening local injury, coagulation abnormality, or systemic signs of envenomation
• Start with 4-6 vials/dose IV infused over 1 hr; monitor for 1 hr following infusions for allergic reaction; repeat with additional 4-6 vials if control not achieved with initial dose
• Repeat with 4-6 vials/dose until local tenderness/swelling not significantly progressing, coagulation tests and systemic signs trend toward normal
• Supportive measures for manifestations of envenomation, such as pain, swelling, hypotension, and wound infection

Maintenance

• Maintenance antivenom therapy may be indicated
• Once control achieved, may need to administer 2 vials IV q6hr for up to 18 hr; optimal dosing past 18 hr not established; however, treatment may be continued based on patient contition

 

Pediatric dosage forms and strengths

powder for injection

• Up to 1g/vial (ovine antiserum)

 

Envenomation

Indicated for North American crotalid envenomation by Crotalinae rattlesnakes (eg, cottonmouths/water moccasins, copperheads, rattlesnakes)

The absolute venom dose following snakebite is expected to be the same in children and adults, and therefore, no dosage adjustment for age should be made

InitiaL

• Begin treatment as soon as possible (ideally within 6 hr of snakebite) in patients who develop signs of progressive envenomation including worsening local injury, coagulation abnormality, or systemic signs of envenomation
• Start with 4-6 vials/dose IV infused over 1 hr; monitor following infusions for allergic reaction; repeat with additional 4-6 vials if control not achieved with initial dose
• Repeat with 4-6 vials/dose IV until local local tenderness/swelling not significantly progressing, coagulation tests and systemic signs trend toward normal
• Supportive measures for manifestations of envenomation, such as pain, swelling, hypotension, and wound infection

Maintenance

• Maintenance antivenom therapy may be indicated
• Once control achieved, may need to administer 2 vials IV q6hr for up to 18 hr; optimal dosing past 18 hr not established; however, treatment may be continued is determined to be necessary based on patient condition

 

CroFab, Copperhead Antivenom (Immune FAB) (Crotalidae polyvalent immune FAB (ovine)) adverse (side) effects

Frequency not defined

Pruritus

Rash

Urticaria

Hypotension

Chills

Fever

Anorexia

Nausea

Asthma

Cough

Dyspnea

Wheezing

Anaphylaxis

Anaphylactoid reaction

 

>10%

Hypersensitivity reactions (5-19%)

 

1-10%

Serum sickness (5%)

 

<1%

Angioedema

Chest discomfort

Dizziness

Erythema

Headache

Hyperhydrosis

Lip swelling

Musculoskeletal chest pain

Tachycardia

Tachypnea

Tongue swelling

Tracheal edema

 

Postmarketing reports

Delayed allergic reaction manifested by fever, pruritus and/or rash

Delayed or recurrent coagulopathy or thrombocytopenia

Failure to achieve intial controL

Recurrent swelling refractory to treatment

Thrombocytopenia refractory to treatment

Prolonged hospitalization

Bleeding

Nausea

Tremor

Worsening eye sight

Treatment failure resulting in death

 

Warnings

Contraindications

(Relative) History of hypersensitivity to papaya or papain unless benefits outweigh risks and appropriate anaphylaxis treatment is readily available

 

Cautions

Contains up to 30 mcg of ethyl mercury from thimerosal or approximately 0.03 mg of mercuary per vial or no more than 0.6 mg of mercuary per dose

If patient develop coagulopathy, due to snakebite, monitor for recurrent coagulopathy for up to 1 week or longer

Monitor for anaphylaxis and hypersensitivity reactions; patients with allergies to papain, chymopapain, other papaya extracts, or the pineapple enzyme bromelain may be at risk for hypersensitivity reaction

Use treatment within 4-6 hr of envenomation to prevent clinical deterioration and development of coagulation abnormalities

 

Pregnancy and lactation

Pregnancy category: C

Lactation: Excretion in milk unknown; use with caution

 

Pregnancy categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

 

Pharmacology of CroFab, Copperhead Antivenom (Immune FAB) (Crotalidae polyvalent immune FAB (ovine))

Mechanism of action

Venom-specific Fab fragment of immunoglobulin G (IgG) that works by binding and neutralizing the venom toxins and facilitate their redistribution away from the target tissue and their elimination from the body

 

Absorption

Onset: Within 1 hr of administration

 

Distribution

Vd (total Fab): 300 mL/kg

 

Elimination

Systemic clearance: 32 mL/min (approximately 0.4 mL/min/kg)

Half-life: 12-23 hr

 

Administration

IV Preparation

Inspect visually for particulate matter and discoloration prior to administration

Reconstitute each vial in 18 mL of 0.9% saline and mix; do not shake

Further dilute content of reconstituted vials in 250 mL of 0.9% NaCl; mix gently

Use within 4 hr of reconstitution

 

IV Administration

IV infusion over 60 min

Infuse slowly over first 10 min at 25-50 mL/hr rate with careful observation for allergic reaction

If no allergic reaction, increase infusion rate to 250 mL/hr

Administer within 6 hr of snakebite advised

 

Storage

Refrigerate virgin vials, don't freeze