botulism antitoxin, heptavalent

General

Pronunciation:
bot–yoo-lizm an-ti-toks-in hep-ta-vay-lent

Trade Name(s)

• BAT

Ther. Class.

antidotes

Pharm. Class.

immune globulins

Indications

Treatment of symptomatic botulism after documented/suspected exposure to botulism neurotoxins A, B, C, D, E, F or G.

Action

Contains antibody fragments prepared from immunized horses. Provides passive immunization by binding the neurotoxins, bound complex is then cleared from circulation.

Therapeutic Effect(s):

Decreased duration/sequelae of neurotoxin poisoning (muscle paralysis) in botulism.

Pharmacokinetics

Absorption: IV administration results in complete bioavailability

Distribution: Unknown.

Metabolism and Excretion: Neurotoxin/antitoxin complex cleared by organs involved in immune processing

Half-life: Serotype A antitoxin– 8.6 hr,  serotype B antitoxin– 34.3 hr,  serotype C antitoxin–  29.6 hr,  serotype D antitoxin– 7.5 hr,  serotype E antitoxin– 7.7 hr,  serotype F antitoxin– 14.1 hr,  serotype G antitoxin– 11.7 hr–

TIME/ACTION PROFILE (preservation of muscle function)

Contraindication/Precautions

Contraindicated in:

• None.

Use Cautiously in:

• Patients at risk of acute hypersensitivity reactions, including history of hypersensitivity to horses, equine products, asthma or hay fever (consider skin sensitivity testing)
• OB:  Use only if benefits outweigh risks
• Lactation: Use cautiously if breastfeeding

Adverse Reactions/Side Effects

CV: edema, vasovagal reaction

GI: nausea

Derm: pruritus, urticaria, rash

MS: arthralgia, myalgia

Neuro: headache, fatigue

Misc: chills, fever, delayed allergic reactions including serum sickness, hypersensitivity reactions including anaphylaxis, infusion reactions, tranmission of infectious agents (equine plasma source)

* CAPITALS indicate life-threatening.
Underline indicate most frequent.

Interactions

Drug-Drug

May interfere with blood glucose testing due to presense of maltose and alter decisions regarding  insulin  and  antidiabetic agents  (use glucose-specific test).

Route/Dosage

IV (Adults and Children ≥17 yr): One vial.

IV (Children 1 – <17 yr): Body weight > 55 kg– 100% of adult dose;  body weight 50–54 kg– 80% of adult dose;  body weight 45–49 kg– 75% of the adult dose;  body weight 40–44 kg– 70% of adult dose;  body weight 35–39 kg– 65% of adult dose;  body weight 30–34 kg– 60% of adult dose;  body weight 25–29 kg– 50% of adult dose;  body weight 20–24 kg– 40% of adult dose;  body weight 15–19 kg– 30% of adult dose;  body weight 10–14 kg– 20% of adult dose.

IV (Infants <1 yr): 10% of the adult dose.

Availability

Solution for injection (requires dilution, contains maltose): serotype A antitoxin 4,500 U, serotype B antitoxin 3,300 U, serotype C antitoxin 3,000 U, serotype D antitoxin 600 U, serotype E antitoxin 5,100 U, serotype F antitoxin 3,000 U, serotype G antitoxin 600 U /vial

Assessment

• Assess severity of symptoms of botulism (double vision, blurred vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth, muscle weakness that spreads through body, difficulty breathing ) during therapy. May occur as early as three hours or as late as a few days. May take wk or mo to resolve.
• Monitor vital signs during infusion. If tolerated, infusion rate can be increased incrementally up to maximum infusion rate, and continued for remainder of administration. Decrease infusion rate if discomfort or infusion-related adverse reactions occur.
• Assess for infusion reactions (chills, fever, headaches, nausea, vomiting, arthralgia, myalgia, fatigue, vasovagal reactions). Reduce rate of infusion; if continues or worsens, discontinue infusion.

• Monitor for signs and symptoms of allergic reaction (urticaria, pruritus, erythema, angioedema, bronchospasm, wheezing, cough, stridor, laryngeal edema, hypotension, tachycardia) during and following infusion. If reaction occurs, immediately discontinue infusion and administer emergency care. Patients allergic to horses, or those with asthma and hay fever are at greatest risk.

Lab Test Considerations:

Maltose in infusion may interfere with glucose monitoring based on glucose dehydrogenase pyrroloquinoline-quinone (GDH-PQQ) method leading to falsely ↑ blood glucose and excess insulin administered. Use only test systems that are glucose specific.

Potential Diagnoses

• Risk for infection (Indications) 
• Deficient knowledge, related to disease process and medication regimen (Patient/Family/Teaching) 

Implementation

• Administer in a facility medication, personnel, and equipment to deal with anaphylaxis.
• Skin Test: For patients at risk of acute hypersensitivity reactions, consider skin sensitivity testing. Administer of 0.02 mL of 1:1000 saline-diluted botulism antitoxin heptavalent intradermally on palmar surface of forearm. If test is negative, repeat test using 1:100 dilution. Perform concurrent positive (histamine) and negative (saline) control tests. A positive test is a wheal with surrounding erythema at least 3 millimeters larger than negative control test; read at 15–20 minutes. Histamine control must be positive for valid interpretation.
• Intermittent Infusion:  Bring vial to room temperature; thaw by placing in warm water bath for 1 hr. Dilution:  Dilute 1:10 in 0.9% NaCl by adding solution from vial to appropriate amount of saline in an IV bag. Do not use any other diluents. As fill volume per vial varies by lot number (10 to 22 mL per vial), 90 to 200 mL of 0.9% NaCl will be needed. Withdraw entire contents of vial to obtain total volume in vial. If a partial vial is required (for pediatric dosing), withdraw entire contents of vial to ensure accurate dose calculation. Do not shake. Do not use solutions that are turbid, cloudy, or contain particles. Discard unused portion.
• Rate: 

  Infuse slowly. Use an intravenous line with constant infusion pump. Use of an in line filter is optional. Infuse at lowest rate possible for patients with risk for hypersensitivity.  For adults,  begin infusion at 0.5 mL/min; may double rate every 30 min as tolerated to a maximum of 2 mL/min.

  • For children 1–17 years old,  begin infusion at 0.01 mL/kg/min; do not exceed adult rate. May increase by 0.01 mL/kg/min every 30 min if tolerated to a maximum of 0.03 mL/kg/min. Do not exceed adult rate.
  • For infants <1 year,  begin infusion at 0.01 mL/kg/min; may increase by 0.01 mL/kg/min every 30 min if tolerated up to a maximum of 0.03 mL/kg/min.

Patient/Family Teaching

• Explain purpose of medication to patient.
• Advise patient to report signs and symptoms of delayed allergic reactions (serum sickness, fever, urticarial or maculopapular rash, myalgia, arthralgia, lymphadenopathy) to health care professional promptly. Usually occurs 10–21 days after infusion, but may occur sooner.
• Inform patient that despite screening of horses, botulism antitoxin heptavalent is prepared from equine plasma and may contain infectious agents such as viruses that can cause disease.
• Advise female patient to notify health care professional if pregnancy is planned or suspected or if breastfeeding.

Evaluation/Desired Outcomes

Decreased duration/sequelae of neurotoxin poisoning (muscle paralysis) in botulism.