CroFab
Generic name: antivenin (Crotalidae) polyvalent
Brand names: Anavip, CroFab
Drug class: Antitoxins and antivenins
Medically reviewed by A Ras MD.
What is CroFab?
CroFab is a prescription medicine that is used to treat some snake bites.
Description
CROFAB [Crotalidae Polyvalent Immune Fab (Ovine)] is a sterile, nonpyrogenic, purified, lyophilized preparation of ovine Fab (monovalent) immunoglobulin fragments obtained from the blood of healthy sheep flocks immunized with one of the following North American snake venoms: Crotalus atrox (Western Diamondback rattlesnake), Crotalus adamanteus (Eastern Diamondback rattlesnake), Crotalus scutulatus (Mojave rattlesnake), and Agkistrodon piscivorus (Cottonmouth or Water Moccasin).
To obtain the final antivenin product, the four different monospecific antivenins are mixed. Each monospecific antivenin is prepared by fractionating the immunoglobulin from the ovine serum, digesting it with papain, and isolating the venom specific Fab fragments on ion exchange and affinity chromatography columns.
CROFAB is standardized by its ability to neutralize the lethal action of each of the four venom immunogens following intravenous injection in mice. The potency of the product will vary from batch to batch; however, a minimum number of mouse LD50 neutralizing units against each of the four venoms is included in every vial of final product,
| 1 One neutralizing unit is determined as the amount of the mixed monospecific Fab proteins necessary to neutralize one LD50 of each of the four venoms, where the LD50 is the amount of venom that would be lethal in 50% of mice. | |||
| 2 As of 2008, the potency assay has been optimized for a new strain of mice, which has resulted in changes to the minimum mouse LD50 neutralizing units. These changes do not reflect any change in product potency, but only a different biological response of the mouse strain to the venom. | |||
| Venom | Minimum Potency per Vial of CROFAB2 | ||
| Crotalus atrox | ≥ 1270 | ||
| Crotalus adamanteus | ≥ 420 | ||
| Crotalus scutulatus | ≥ 5570 | ||
| Agkistrodon piscivorus | ≥ 780 | ||
Each vial of CROFAB contains up to 1 gram of total protein and sodium phosphate buffer consisting of dibasic sodium phosphate USP and sodium chloride USP. The product is intended for intravenous administration after reconstitution with 18 mL of 0.9% Sodium Chloride.
Mechanism of Action
CROFAB is a venom-specific Fab fragment of immunoglobulin G (IgG) that works by binding and neutralizing venom toxins, facilitating their redistribution away from target tissues and their elimination from the body.
Before taking CroFab, tell your doctor:
- If you are allergic to CroFab; any part of this medicine; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
This medicine may interact with other drugs or health problems.
Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take CroFab with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.
What are some things I need to know or do while I take CroFab?
- Tell all of your health care providers that you take CroFab. This includes your doctors, nurses, pharmacists, and dentists.
- Allergic reactions can happen with CroFab. Some allergic reactions may happen some time after CroFab has been given. Call your doctor right away if you have any signs that are not normal after getting CroFab.
- Bleeding problems may happen after snake bites. Call your doctor right away if you have any unexplained bruising or bleeding within 2 weeks after the snake bite.
- Use with care in children. Talk with the doctor.
- Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using CroFab while you are pregnant.
- Tell your doctor if you are breast-feeding. You will need to talk about any risks to your baby.
How is CroFab best taken?
Use CroFab as ordered by your doctor. Read all information given to you. Follow all instructions closely.
- It is given as an infusion into a vein over a period of time.
What do I do if I miss a dose?
- Call your doctor to find out what to do.
What are the side effects of CroFab that I need to call my doctor about immediately?
WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:
- Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
- Wheezing or coughing.
- Very bad dizziness or passing out.
- A fast heartbeat.
- Fever.
- Muscle or joint pain.
What are some other side effects of CroFab?
All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:
- Itching.
- Upset stomach.
- Back pain.
These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.
If overdose is suspected:
If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.
How do I store and/or throw out CroFab?
- If you need to store CroFab at home, talk with your doctor, nurse, or pharmacist about how to store it.
Label
PRINCIPAL DISPLAY PANEL – NDC 50633-110-11 – VIAL LABEL
