May cause dose-dependent seizures; contraindicated in prior history of seizure; use should be discontinued if seizure occurs. Contraindicated in moderate or severe renal impairment (CrCl ≤50 mL/min); the risk of seizures in mild renal impairment (CrCl: 51-80 mL/min) is unknown. Should not be taken with other forms of 4-aminopyridine (4-AP, fampridine), since the active ingredient is the same. Urinary tract infections were reported more frequently in patients receiving this treatment compared to placebo.