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  • CLASSES

    Other Antitoxic Sera

    DEA CLASS

    Rx

    DESCRIPTION

    Polyvalent antivenin useful against scorpion stings.
    First specific treatment to neutralize toxin from Centruroides scorpion stings, particularly Centruroides sculpturatus in the United States; children and infants are more likely than adults to have severe stings and resulting symptoms and hospitalization.
    Derived from equine plasma; early and delayed hypersensitivity reactions are possible.

    COMMON BRAND NAMES

    Anascorp

    HOW SUPPLIED

    Anascorp Intravenous Inj Pwd F/Sol

    DOSAGE & INDICATIONS

    For the treatment of Centruroides scorpion sting in patients with clinically significant signs of envenomation.
    NOTE: Mild envenomation in adults usually causes local pain and does not require specific treatment. Clinically significant stings result in neurotoxicity (e.g., uncoordinated neuromotor hyperactivity, oculomotor and visual abnormalities, and respiratory compromise). Significant envenomation is more likely in young children. In North America, scorpions whose venom has medical consequences fall within one genus, Centruroides. In the United States there is a single neurotoxic species, Centruroides sculpturatus (previously known as C. exilicauda).
    Intravenous dosage (Anascorp)
    Neonates, Infants, Children, Adolescents, and Adults

    The initial dose is 3 vials of antivenin diluted to a total volume of 50 mL normal saline and administered IV over 10 minutes. Additional doses of 1 vial of antivenin diluted to a total volume of 50 mL normal saline and administered IV over 10 minutes may be given at 30- to 60-minute intervals as needed. Data from use in Mexico and Arizona, including data in critically ill children (age 6 months to 18 years) from a double-blind, placebo-controlled study , suggest that use of the antivenin in most patients can resolve significant clinical toxicity within about 4 hours after treatment.

    MAXIMUM DOSAGE

    Adults

    No maximum dosage information can be definitely assigned at this time.

    Geriatric

    No maximum dosage information can be definitely assigned at this time.

    Adolescents

    No maximum dosage information can be definitely assigned at this time.

    Children

    No maximum dosage information can be definitely assigned at this time.

    Infants

    No maximum dosage information can be definitely assigned at this time.

    Neonates

    No maximum dosage information can be definitely assigned at this time.

    DOSING CONSIDERATIONS

    Hepatic Impairment

    Specific guidelines for dosage adjustments in hepatic impairment are not available; it appears that no dosage adjustments are needed.

    Renal Impairment

    Specific guidelines for dosage adjustments in renal impairment are not available; it appears that no dosage adjustments are needed.

    ADMINISTRATION

    Injectable Administration

    Scorpion antivenin is administered intravenously by infusion.
    Visually inspect parenteral products for particulate matter and discoloration prior to administration whenever solution and container permit. Do not use if the solution is turbid.

    Intravenous Administration

    Reconstitution:
    Reconstitute each vial of scorpion antivenin with 5 ml of sterile normal saline.
    Mix by swirling gently.
    If using more than one vial, combine the contents of each vial promptly.
    Further dilute dose to a total volume of 50 ml with sterile normal saline (0.9% NaCl injection).
    Discard any partially used vials.
    Intravenous infusion:
    Infuse dose intravenously over 10 minutes.
    Monitor patient closely during and up to 60 minutes following the infusion completion.

    STORAGE

    Anascorp:
    - Discard unused portion. Do not store for later use.
    - Do not freeze
    - Store at 77 degrees F; brief exposure up to 104 degrees F does not adversely affect product

    CONTRAINDICATIONS / PRECAUTIONS

    Equine protein hypersensitivity, infection, requires a specialized care setting

    Hypersensitivity reactions, including anaphylaxis, may occur following administration of scorpion antivenin. Therefore the administration of antivenin requires a specialized care setting and the patient should be hospitalized if possible. The product is derived from the blood of healthy horses immunized with venom from Centruroides scorpions; therefore, patients with equine protein hypersensitivity or patients who have received previous therapy with equine antivenom/antitoxin may be at higher risk for anaphylaxis. Patients should be monitored for signs of hypersensitivity reactions and emergency medications such as epinephrine, corticosteroids, and diphenhydramine should be readily available. The infusion should be terminated and emergency medical care instituted if hypersensitivity reactions develop. Patients should also be monitored for delayed allergic reactions (serum sickness). Scorpion antivenin carries a risk of transmitting infection, such as from viruses, due to the equine source of the product.

    Cresol hypersensitivity

    Scorpion antivenin contains trace amounts of cresol and should be avoided in patients with cresol hypersensitivity; localized reactions and general myalgias have been reported with the use of cresol as an injectable excipient.

    Pregnancy

    Scorpion antivenin is classified as a FDA pregnancy risk category C. It is not known whether scorpion antivenin causes fetal harm when administered to a pregnant woman and animal reproduction studies have not been conducted. Scorpion antivenin should only be administered to a pregnant woman if the benefit clearly outweighs the risk.

    Breast-feeding

    It is not known whether scorpion antivenin is excreted in breast milk; caution should be used when administering to a breast-feeding woman. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally administered drug, health care providers are encouraged to report the adverse effect to the FDA.

    ADVERSE REACTIONS

    Severe

    serum sickness / Delayed / 0.5-0.5
    anaphylactoid reactions / Rapid / Incidence not known

    Moderate

    ocular inflammation / Early / Incidence not known
    hypoxia / Early / Incidence not known
    ataxia / Delayed / Incidence not known
    palpitations / Early / Incidence not known
    lymphadenopathy / Delayed / Incidence not known

    Mild

    vomiting / Early / 4.7-4.7
    fever / Early / 4.1-4.1
    rash / Early / 2.7-2.7
    nausea / Early / 2.1-2.1
    pruritus / Rapid / 2.0-2.0
    headache / Early / 1.9-1.9
    rhinorrhea / Early / 1.8-1.8
    myalgia / Early / 1.6-1.6
    fatigue / Early / 1.6-1.6
    cough / Delayed / 1.4-1.4
    diarrhea / Early / 1.3-1.3
    lethargy / Early / 1.1-1.1

    DRUG INTERACTIONS

    There are no drug interactions associated with Scorpion Antivenin, Antivenin Centruroides sculpturatus Equine products.

    PREGNANCY AND LACTATION

    Pregnancy

    Scorpion antivenin is classified as a FDA pregnancy risk category C. It is not known whether scorpion antivenin causes fetal harm when administered to a pregnant woman and animal reproduction studies have not been conducted. Scorpion antivenin should only be administered to a pregnant woman if the benefit clearly outweighs the risk.

    It is not known whether scorpion antivenin is excreted in breast milk; caution should be used when administering to a breast-feeding woman. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally administered drug, health care providers are encouraged to report the adverse effect to the FDA.

    MECHANISM OF ACTION

    The clinical consequences of scorpion envenomation are the result of ion channel specific toxins present in the venom which stimulate action potentials throughout the peripheral nervous system. Scorpion antivenin is composed of venom specific F(ab')2 fragments of immunoglobulin G. These fragments bind and neutralize the toxins allowing for redistribution away from target tissues and elimination from the body.

    PHARMACOKINETICS

    Intravenous Route

    Scorpion antivenin is administered intravenously. In clinical trials, 95—100% of patients responded to scorpion antivenin with relief of systemic symptoms in less than four hours after initiating treatment. Scorpion antivenin is standardized for potency in mice in terms of its LD50 neutralizing capacity per mL. Based on this assay system, the reconstituted contents of each vial (5 mL) will neutralize approximately 150 LD50 of Centruroides scorpion venom and contains no more than 120 mg of protein. In a pharmacokinetic study, 47.5 mg of scorpion antivenin was administered to eight healthy adult volunteers and blood samples were collected over 21 days. The following pharmacokinetic parameters were reported (mean +/- standard deviation): area under the curve (AUC) 706 +/- 352 mcg/ml x hr, clearance 83.5 +/- 38.4 ml/hr, half-life 159 +/- 57 hrs, and volume of distribution at steady-state 13.6 +/- 5.4 L.