Dalfampridine

Clinical summary

Indications and usage 1 INDICATIONS AND USAGE Dalfampridine Extended-Release Tablets are 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 Tablets are 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 ). Dosage and administration 2 DOSAGE AND ADMINISTRATION The maximum recommended dosage is 10 mg twice daily (approximately 12 hours apart). There is no evidence of additional benefit with doses greater than 10 mg twice daily. Adverse reactions, including seizures, were more frequent at higher doses. ( 2.1 ) Take with or without food. Administer tablets whole; do not divide, crush, chew, or dissolve ( 2.2 ) Patients should not take double or extra doses if they miss a dose. ( 2.2 ) Estimated creatinine clearance (CrCl) should be known before initiating treatment with Dalfampridine Extended-Release Tablets. In patients with mild renal impairment (CrCl 51 to 80 mL/min), Dalfampridine Extended-Release Tablets may reach plasma levels associated with a greater risk of seizures, and the potential benefits of Dalfampridine Extended-Release Tablets should be carefully considered against the risk of seizures in these patients ( 2.3 , 5.2 , 8.6 ) 2.1 Dosage Information The maximum recommended dosage of Dalfampridine Extended-Release Tablet is one 10 mg tablet twice daily and should not be exceeded. Take doses approximately 12 hours apart. There is no evidence of additional benefit at doses greater than 10 mg twice daily. Adverse reactions, including seizures, and discontinuations because of adverse reactions were more frequent at higher doses. 2.2 Administration Instructions Dalfampridine Extended-Release Tablets can be taken with or without food. Administer tablets whole; do not divide, crush, chew, or dissolve Dalfampridine Extended-Release Tablets. If a dose is missed, patients should not take double or extra doses. 2.3 Renal Monitoring Prior to and During Treatment Estimated creatinine clearance (CrCl) should be known before initiating treatment with Dalfampridine Extended-Release Tablets, and monitored at least annually during treatment with Dalfampridine Extended-Release Tablets. CrCl can be estimated using the following equation (multiply by 0.85 for women): CrCl = (140 - age ) × weight ( kg ) SerumCr ( mg / dl )× 72 2.4 Dosage in Patients with Renal Impairment In patients with mild renal impairment (CrCl 51 to 80 mL/min), Dalfampridine Extended-Release Tablets plasma levels may approach those seen at a dose of 15 mg twice daily, a dose that is 1.5 times the maximum recommended dose and may be associated with an increased risk of seizures. As mild renal impairment is common after age 50, estimating CrCl is particularly important in these patients. The potential benefits of Dalfampridine Extended-Release Tablets should be carefully considered against the risk of seizures in these patients [see Warnings and Precautions (5.2) and Clinical Pharmacology (12.3) ]. Dalfampridine Extended-Release Tablets are contraindicated in patients with moderate or severe renal impairment (CrCl≤50 mL/min). Warnings and cautions 5 WARNINGS AND PRECAUTIONS Dalfampridine can cause seizures; the risk of seizures increases with increasing Dalfampridine Extended-Release Tablets doses; discontinue Dalfampridine Extended-Release Tablets 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 Extended-Release Tablets if this occurs ( 5.4 ) 5.1 Seizures 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 Extended-Release Tablets in patients with MS. In open-label extension trials in MS patients, the incidence of seizures during treatment with Dalfampridine Extended-Release Tablets 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 Extended-Release Tablets have 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 Extended-Release Tablets clinical stu