Vaccines, Blood & Biologics

Extension of Expiration Date for Black Widow Spider Antivenin Lot 0667018 (in packaged lot 0585Z) until February 12, 2013 And Instructions for Diluent Use


Important Notification
This is to provide you with important information regarding Antivenin (Latrodectus mactans) (Equine), commonly referred to as Black Widow Spider Antivenin (BWSA). Black Widow Spider Antivenin is indicated for patients with symptoms due to bites by the Black Widow spider. This product is manufactured by Merck and Company, Inc. Due to limited supplies, Merck currently ships BWSA only for patients with symptomatic bites, within 24 hours of notification (see Merck contact information, below). nbsp; 
Packaged Lot 0585Z has a labeled expiration date of 6/30/2012. The packaged lot contains a) Antivenin (BWSA) lot 0667018; b) sterile diluent (water for injection), and c) horse serum for sensitivity testing.  FDA has extended the expiration date for BWSA lot 0667018, contained in packaged lot 0585Z based on stability data provided by Merck.  The new expiration date for BWSA lot 0667018 is February 12, 2013.
Instructions for diluent use
Do not use the expired diluent packaged with BWSA.   Instead, reconstitute the BWSA with 2.5 mL of Sterile Water for Injection.   Then proceed to follow the package insert instructions under DOSAGE AND ADMINISTRATION. 
Related Information:
  • To urgently obtain BWSA for patients with confirmed symptomatic bites, you should call the Merck National Service Center Call Line at:
            1-800- 672-6372.  

Contact FDA

(800) 835-4709
(240) 402-8010
Consumer Affairs Branch (CBER)

Division of Communication and Consumer Affairs

Office of Communication, Outreach and Development

Food and Drug Administration

10903 New Hampshire Avenue

Building 71 Room 3103

Silver Spring, MD 20993-0002

Page Last Updated: 08/16/2012
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