US Generic Antiseizure Medication Supply Chain: Observations from Analysis of US Government Databases

Generic drug manufacturing has shifted away from the U.S. in the last few decades. The medication supply chain, from manufacturers to resellers, has become increasingly globalized and complex. This has led to bottlenecks in their manufacture resulting in medication shortages. Review of this process as it pertains to antiseizure medications (ASM) shows gaps in our comprehension of its complexities. Understanding these processes will be essential for preventing medication shortages.

The aim of this research is to examine the generic ASM supply with an emphasis on production, labeling, and repackaging.

Data from the United States Food and Drug Administration (FDA) and the National Library of Medicine (NLM) website DailyMed was used to evaluate supply chain details to gather information on antiseizure medication formulations, manufacturing locations, and labeling.

Out of 3142 ASM-related active National Drug Code (NDC-9) codes, 2663 NDC-9 codes with Abbreviated New Drug Application (ANDA) status were included in the analysis. Most (94.8 %) were enteral, with only 5.2 % being parenteral (intravenous and intramuscular route). We identified the manufacturing country for 82 % of these codes, corresponding to 306 unique ANDA numbers. 119 manufacturing sites in 12 countries produce generic ASM Finished Dosage Forms (FDF): 103 for enteral and 21 for parenteral. India is the main producer of enteral ASM FDFs with 49 sites, followed by the US with 36. Regarding parenteral formulation, five countries had 21 unique manufacturing locations. 42 % of the 103 enteral ASM FDFs manufacturing sites produced multiple ASM FDFs, with one facility making eight distinct ASMs. 34.4 % of facilities were associated with over 3 ANDAs, and 15.1 % with more than 5. 22.7 % of ANDAs lacked a manufacturing facility identifier. Repackaged ASM FDFs constituted 48 % of NDC-9 s. Gabapentin and pregabalin were the most common oral ASMs.

India is the major source for generic ASM FDFs manufacturing, leading to concerns about overall supply dependency on that country. There is a paucity of facilities for the global supply of parenteral ASM FDFs. There is missing data for many NDC-9 codes emphasizing urgency for transparency in the supply chain.