Atypical Post-Injection Reactions with Delayed Onset Following Glatiramer Acetate 40 mg: Need for Titration?

Atypical PIRs with GA40, especially gastrointestinal symptoms and/or fever/shivering, had a delayed onset and occurred in a significant proportion of our patients. Their real prevalence should be assessed in appropriately designed studies accounting for  nocebo responses. Initial dose titration might reduce PIR frequency.