Products Affected - Description

• • Antivenin Lactrodectus Mactans (Black Widow Spider Antivenin) powder for solution for injection, Merck, 6000 units, vial, 1 count, NDC 00006-5424-02

Reason for the Shortage

• • Merck has low inventory of Antivenin Latrodectus Mactans. They could not provide a reason for the shortage.

Available Products

• • There is insufficient supply for usual ordering

• • Merck is accepting drop ship orders for a maximum of 2 doses at a time. Merck could not provide an estimate for when supply will improve.

• • Merck is the sole supplier of Antivenin Latrodectus Mactans
  • Antivenin latrodectus is used to treat envenomation from black widow (Latrodectus mactans) bites. [1]

• • Reserve antivenin for patients presenting with severe symptoms who are refractory to supportive care. Additional priority may be given to children and older adults with comorbidities. [2]
  • Antivenin Latrodectus is associated with anaphylaxis in up to 5% of patients.[2 3]
  • History of asthma and atopy are considered contraindications to receiving Antivenin latrodectus. [3 4]

• 1. Antivenin (Latrodectus mactans). UpToDate Lexidrug, Lexi-Drugs Online. Waltham, MA, 2023.
  2. Herness J, Snyder MJ, Newman RS. Arthropod Bites and Stings. American family physician 2022;106(2):137-47
  3. Williams M, Sehgal N, Nappe TM. Black Widow Spider Toxicity. StatPearls. Treasure Island (FL) ineligible companies.: StatPearls Publishing
  4. Caruso MB, Lauria PSS, de Souza CMV, Casais ESLL, Zingali RB. Widow spiders in the New World: a review on Latrodectus Walckenaer, 1805 (Theridiidae) and latrodectism in the Americas. The journal of venomous animals and toxins including tropical diseases 2021;27:e20210011 doi: 10.1590/1678-9199-jvatitd-2021-0011[published Online First: Epub Date]|.