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| Primary information |
|---|
| ID | 15295 |
| Therapeutic ID | Th1582 |
| Protein Name | Crotalus atrox antivenin |
| Sequence | >Th1582_Crotalus_atrox_antivenin
LLRRKSHDHAQNHDGDKCLRGASLGYYQSFLNQYKPQCILNKP
|
| Molecular Weight | NA |
| Chemical Formula | NA |
| Isoelectric Point | NA |
| Hydrophobicity | NA |
| Melting point | NA |
| Half-life | 12-23 hours [F113] |
| Description | Each year it is estimated there are 45,000 snakebites in the US and 300,000 to 400,000 bites worldwide. About 8000 of these snakebites involve venomous snake species. The majority of people bitten are males and about 50% occur in the age group of 18 to 28 [F113]. Crotalus atrox antivenin is derived and purified immunoglobulin fragments obtained from other domestic animals such as sheep previously immunized with Crotalus atrox (Western Diamondback rattlesnake). Bites from this snake are the most common in the state of Texas, USA [A33157]. The final purified antivenin product is produced by mixing other different monospecific snake antivenins and isolating the antivenin of interest through fractionation and chromatography techniques. It is intravenously (IV) administered to prevent/limit systemic toxicity [FDA label]. |
| Indication/Disease | CROFAB is indicated for the management of adult and pediatric patients with North American crotalid envenomation. The term crotalid is used to describe the Crotalinae subfamily (formerly known as Crotalidae) of venomous snakes which includes rattlesnakes, copperheads and cottonmouths/water moccasins [FDA label]. |
| Pharmacodynamics | Crotalus atrox venom contains agents that render human fibrinogen and plasma incoagulable by thrombin [A33158]. CROFAB antivenom reverses these effects [FDA label]. This facilitates re-distribution of venom toxins away from target tissues and elimination from the body [L2874]. It is a mixture of 4 different monospecific antivenoms derived from serum of healthy sheep immunized with one of the following North American snake venoms: C. atrox (Western diamondback rattlesnake), C. adamanteus (Eastern diamondback rattlesnake), C. scutulatus (Mojave rattlesnake), or A. piscivorus (cottonmouth or water moccasin) [L2874]. |
| Mechanism of Action | CROFAB consists of venom-specific Fab fragments of immunoglobulin G (IgG) that work by binding to and neutralizing venom toxins, facilitating their redistribution away from target tissues and their elimination from the body [L2868]. CROFAB contains only the Fab fragments from ovine-derived immunoglobulins. The enzyme _papain_ is used to cleave the IgG antibody, creating 2 separate Fab fragments and 1 Fc fragment. After the cleavage step, another protein binds to the Fc fragments, which are not essential for binding snake venom, allowing the pure Fab fragments to be recovered.The Fab fragments of an immunoglobulin contain the variable regions that recognize and bind to specific antigens [L2868]. |
| Toxicity | Most common adverse reactions (incidence =5% of subjects) were urticaria, rash nausea, pruritus and back pain [FDA label]. Severe hypersensitivity reactions may occur with the use of CROFAB. In case of acute hypersensitivity reactions, including anaphylaxis and anaphylactoid reactions, discontinue infusion and institute appropriate emergency treatment [FDA label]. CROFAB contains purified immunoglobulin fragments from the blood of sheep that have been immunized with snake venoms. Injection of heterologous animal proteins can lead to severe acute and delayed hypersensitivity reactions (late serum reaction or serum sickness) and a possible febrile response to immune complexes formed by animal antibodies and neutralized venom components. _Papain_ enzyme is used to cleave antibodies into fragments during the processing of CROFAB, and negligible amounts of papain or inactivated papain residues may be present. Patients allergic to papain, chymopapain, other papaya extracts, or the pineapple enzyme bromelain may also have an allergic reaction to CROFAB. Certain dust mite allergens and some latex allergens share antigenic structures with papain and patients with these allergies may be allergic to papain [FDA label]. |
| Metabolism | NA |
| Absorption | NA |
| NA |
| Clearance | NA |
| Categories | Venom Neutralization |
| Patents Number | NA |
| Date of Issue | NA |
| Date of Expiry | NA |
| Drug Interaction | NA |
| Target | NA |
| Brand Name | NA |
| Company | NA |
| Brand Description | NA |
| Prescribed For | NA |
| Chemical Name | NA |
| Formulation | NA |
| Physical Appearance | NA |
| Route of Administration | NA |
| Recommended Dosage | NA |
| Contraindication | NA |
| Side Effects | NA |
| Useful Link 1 | Link |
| Useful Link 2 | NA |
| Remarks | NA |