Safety profile of dalfampridine extended release in multiple sclerosis: 5-year postmarketing experience in the United States

Figures & data

Table 1 Demographic characteristics of dalfampridine-ER users

	Dalfampridine-ER usersa	Dalfampridine-ER users with reported adverse eventsb
Mean age, years	52.1	55.3
Age distribution (n, %)
<35 years	6,054 (6.9)	484 (3.5)
35–44 years	15,281 (17.4)	1,611 (11.8)
45–54 years	28,372 (32.3)	3,894 (28.5)
55–64 years	27,292 (31.1)	5,087 (37.2)
≥65 years	11,425 (13.0)	2,605 (19.0)
Female, n (%)	61,735 (70.3)	18,247 (75.0)

Notes:

a Demographic data available for 82% (87,815) of dalfampridine-ER users (N=107,000);

b age information available for 54% (n=13,681) and sex information available for 95% (n=24,317) of dalfampridine-ER users with adverse events reported (n=25,526).

Abbreviation: Dalfampridine-ER, dalfampridine extended release tablets.

Table 2 Most commonly reported adverse events (≥2% of all reported events; N=60,949

MedDRA preferred term	n (percent of total events)	Event status
Dizziness	2,231 (3.7)	Labeled
Insomnia	1,955 (3.2)	Labeled
Balance disorder	1,839 (3.0)	Labeled
Headache	1,457 (2.4)	Labeled
Nausea	1,269 (2.1)	Labeled
Urinary tract infection	1,215 (2.0)	Labeled
Inappropriate schedule of drug administration	1,881 (3.1)	Not listed
Fall	1,480 (2.4)	Not listed
Gait disturbance	2,786 (4.6)	Not listed
Drug ineffective	3,544 (5.8)	Expected

Abbreviation: MedDRA, Medical Dictionary for Regulatory Activities.

Table 3 Reported seizure cases in the first 5 years of postmarketing surveillance of dalfampridine-ER

	All cases (n=657)	Medically confirmed casesa (n=324)	Other cases (n=333)
Time to onset, n (%)
Within 7 days of treatment initiation	79 (12)	35 (11)	44 (13)
Within 30 days of treatment initiation	142 (22)	66 (20)	76 (23)
Unknown	266 (40)	122 (38)	144 (43)
Incidence rate, per 1,000 patient-years
Overall	6.3	3.1	3.2
Incidence rate after first week	5.7	2.8	2.8
Incidence rate after first month	5.4	2.7	2.7
Seizure risk factors, n (%)
Prior history of seizures	43 (7)	26 (8)	17 (5)
Concomitant use of bupropion or tramadolb	47 (7)	25 (8)	22 (7)
History of renal impairment	6 (1)	2 (0.6)	4 (1)

Notes:

a Seizure cases that are reported or confirmed by a health care practitioner;

b medications that are known to lower the seizure threshold.

Abbreviation: Dalfampridine-ER, dalfampridine extended release tablets.

Figure 1 Cumulative incidence of seizure events.

Note: Values represent total cases reported to date divided by the total patient-years to date calculated for each time period and displayed per 1,000 patient-years.
Abbreviation: Q, quarter.