antivenom black widow spider [IM/IV]

Adult Dosing

Black widow spider bite

Reconstitute in 2.5 mL of sterile diluent
Administer 2.5 mL of reconstituted antivenom IM (anterolateral thigh); may repeat after 1-3 hrs

Dilute reconstituted antivenom in 10-50 mL of 0.9% sodium chloride injection and infuse 2.5 mL IV over a 15-minute period; may repeat after 1-3 hrs

Note:

Prior to the administration of antivenom, a skin or conjunctival sensitivity test is recommended
IV infusion is preferred for the management of severe black widow spider envenomation or when the patient is in shock

Pediatric Dosing

Black widow spider bite (<12 yrs)

Dilute reconstituted antivenom in 10-50 mL of 0.9% sodium chloride injection and infuse 2.5 mL IV over a 15-minute period; may repeat after 1-3 hrs

Black widow spider bite (>12 yrs)

Reconstitute in 2.5 mL of sterile diluent
Administer 2.5 mL of reconstituted antivenom IM (anterolateral thigh); may repeat after 1-3 hrs

Dilute reconstituted antivenom in 10-50 mL of 0.9% sodium chloride injection and infuse 2.5 mL IV over a 15-minute period; may repeat after 1-3 hrs

Notes:

Prior to the administration of antivenom, a skin or conjunctival sensitivity test is recommended
IV infusion is preferred for the management of severe black widow spider envenomation or when the patient is in shock or under 12 years of age

[Outline]

Adult Dosing
Pediatric Dosing

Indications ⬆ ⬇

Treatment of symptoms due to bites by the black widow spider (Latrodectus mactans); early use is emphasized for prompt relief

Contraindications ⬆ ⬇

Hypersensitivity to any of the ingredients of the product
Hypersensitivity to horse serum

Black Box Warnings ⬆ ⬇

Dosing Adjustment ⬆ ⬇

Renal Dose Adjustment

Renal impairment: Dose adjustments not defined

Hepatic Dose Adjustment

Hepatic impairment: Dose adjustments not defined

Warnings/Precautions ⬆ ⬇

Immediate sensitivity reactions such as anaphylaxis, anaphylactoid reactions, or shock have been rarely reported in patients receiving antivenom. Discontinue therapy, at least temporarily, and initiate appropriate medical therapy including epinephrine, antihistamines, IV fluids and vasopressor agents, maintenance of an adequate airway, and oxygen if a severe immediate sensitivity reaction occurs
Prior to the administration of antivenom black widow spider, a skin or conjunctival test should be performed and a careful review of the patient's history of prior exposure to horse serum or any allergies should be taken
For skin test, inject 0.02 mL of the test material into the skin; appearance of an urticarial wheal surrounded by a zone of erythema in 10 minutes suggests a positive reaction
For conjunctival test, instill 1 drop of 1:10 dilution of horse serum for adults and 1 drop of 1:100 dilution for children into the conjunctival sac. Itching of the eye and reddening of the conjunctiva within 10 minutes indicate a positive reaction
Following the administration of antivenom, observe the patient for serum sickness for an average of 8-12 days
If the history is positive or the results of the sensitivity tests are mildly or questionably positive and if the administration of antivenom black widow spider is considered necessary to save life, desensitization should be attempted
For desensitization, prepare 1:10 or 1:100 dilutions of antivenom in sodium chloride for injection in separate sterile vials or syringes. Using a tuberculin syringe, inject subcutaneously 0.1, 0.2 and 0.5 mL of the 1:100 dilution at 15- or 30-minute intervals; repeat with the 1:10 dilution and finally the undiluted antivenom
Place a tourniquet proximal to the sites of injection if reaction occurs after any of the injections and administer epinephrine 1:1000 (0.3-1.0 mL SC or 0.05-0.1 mL IV) proximal to the tourniquet or into another extremity; administer another injection of antivenom after 30 minutes
If no reaction occurs after 0.5 mL of undiluted antivenom, continue the dose at 15-minute intervals until the entire dose has been given
Continuously monitor patients receiving antivenom and keep appropriate equipment for maintenance of an adequate airway and other supportive measures and agents for the treatment of severe systemic reactions readily available during therapy

Pregnancy/Breast Feeding ⬆ ⬇

Pregnancy Category:C

Breastfeeding: It is unknown whether this antivenom is excreted in human milk. Manufacturer advises caution when administered to nursing mothers, as many drugs are excreted in human milk.

Adverse Reactions ⬆ ⬇

HYPERSENSITIVITY: Anaphylaxis, serum sickness
MUSC: Muscle cramps
LOCAL: Injection site pain

Clinical Pharmacology ⬆ ⬇

Venom-neutralizing globulin; exact mode of action is unknown, neutralizes the black widow spider venom
Metabolism: Unknown
Excretion: Unknown
Half-life: Unknown

Brands and Availability ⬆ ⬇