Other nervous system drugs
Dalfampridine
The FDA lists this product in 9 strengths and forms.
Indications
Dalfampridine extended-release tablet is indicated as a treatment to improve walking in adult patients with multiple sclerosis (MS). This was demonstrated by an increase in walking speed [see Clinical Studies (14) ]. Dalfampridine extended-release tablet is a potassium channel blocker indicated to improve walking in adult patients with multiple sclerosis (MS). This was demonstrated by an increase in walking speed (1, 14) .
Contraindications
The use of dalfampridine is contraindicated in the following conditions: History of seizure [see Warnings and Precautions (5.1) ] Moderate or severe renal impairment (CrCl≤50 mL/min) [see Warnings and Precautions (5.2) ] History of hypersensitivity to dalfampridine or 4-aminopyridine; reactions have included anaphylaxis [see Warnings and Precautions (5.4) ] History of seizure (4) Moderate or severe renal impairment (CrCl≤50 mL/min) (4) History of hypersensitivity to dalfampridine or 4-aminopyridine (4)
Warnings and precautions
Dalfampridine can cause seizures; the risk of seizures increases with increasing dalfampridine doses; discontinue dalfampridine and do not restart if a seizure occurs (5.1) Avoid concomitant use with other forms of 4-aminopyridine (4-AP, fampridine), since the active ingredient is the same (5.3) Dalfampridine can cause anaphylaxis. Discontinue and do not restart dalfampridine if this occurs (5.4)
5.1Seizures
Dalfampridine can cause seizures. Increased incidence of seizures has been observed at 20 mg twice daily (2 times the maximum recommended dosage) in controlled clinical studies of 9 to 14 weeks duration with dalfampridine in patients with MS. In open-label extension trials in MS patients, the incidence of seizures during treatment with dalfampridine 15 mg twice daily (1.7/100PY) was over 4 times higher than the incidence during treatment with 10 mg twice daily (0.4/100PY).
In the post-marketing period seizures have been reported. The majority of seizures occurred at the recommended dose and in patients without a history of seizures, and generally within days to weeks of starting therapy. Dalfampridine has not been evaluated in patients with a history of seizures or with evidence of epileptiform activity on an EEG, as these patients were excluded from clinical trials. The risk of seizures in patients with epileptiform activity on an EEG is unknown, and could be substantially higher than that observed in dalfampridine clinical studies.



