Black Widow Spider Antivenin (Latrodectus mactans)(Equine) Packaged Lot 0585Z: Information about Expiration Date and Use
Posted Aug 09 2012 8:05am
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).
FDA has received calls from pharmacies requesting to use Black Widow Spider Antivenin packaged Lot 0585Z. Packaged Lot 0585Z has a labeled expiration date of 6/30/2012. Each BWSA package contains a) Antivenin (BWSA); b) sterile diluent (water for injection), and c) horse serum for sensitivity testing. The expiration date is defined as the earliest expiry among these three components. In the case of Lot 0585Z, the sterile diluent expired on 6/30/2012. The horse serum expires on 3/07/2013, and the BWSA expires on 8/12/2012.
Until 8/12/2012, you may continue to use the BWSA in packaged Lot 0585Z. 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.
FDA is working with Merck to extend the expiration date for BWSA if stability data indicates that Lot 0585Z will remain potent. Expiration date extensions will be posted on this website.
To urgently obtain BWSA for patients with confirmed symptomatic bites, you should call the Merck National Service Center Call Line at:
Package Insert – Black Widow Spider Antivenin (Latrodectus mactans)(Equine)