FDA Pulls Plug on Old Primidone Suspension Forever
Published Date: 1/2/2026
Notice
Summary
The FDA has decided that MYSOLINE (primidone) suspension, 250 mg/5 mL, was taken off the market because it wasn’t safe or effective. This means no new generic versions of this medicine will be approved or sold. Patients and drug makers should note this change to avoid confusion and ensure safety starting now.
Analyzed Economic Effects
2 provisions identified: 1 benefits, 1 costs, 0 mixed.
FDA Blocks New Generics for MYSOLINE
The FDA determined that MYSOLINE (primidone) suspension, 250 mg/5 mL, was withdrawn from sale for reasons of safety or effectiveness and will be removed from the Orange Book. As a result, the Agency will not accept or approve abbreviated new drug applications (ANDAs) that refer to this 250 mg/5 mL suspension. This decision was published in the Federal Register on January 2, 2026.
Product Withdrawn Over Contamination Risk
MYSOLINE (primidone) suspension, 250 mg/5 mL, was discontinued in 2001 after antimicrobial effectiveness testing raised concerns about possible contamination, including with Pseudomonas aeruginosa. Before the product could return to market a reformulation would be required (including preservative content acceptance criteria and passing antimicrobial effectiveness testing) and the NDA holder would need to demonstrate safety and effectiveness; no new formulation is approved at this time.
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