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Details with Side Effects
AMPYRA can cause seizures. Increased incidence of seizures has been observed at 20 mg twice daily in controlled clinical studies of 9–14 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.
AMPYRA 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 AMPYRA clinical studies. AMPYRA should be discontinued and not restarted in patients who experience a seizure while on treatment. AMPYRA is contraindicated in patients with a history of seizures [see CONTRAINDICATIONS].
AMPYRA is eliminated through the kidneys primarily as unchanged drug [see CLINICAL PHARMACOLOGY].
Because patients with moderate to severe renal impairment (CrCl ≤ 50mL/min) would require a dose lower than 10 mg twice daily and no strength smaller than 10 mg is available, AMPYRA is contraindicated in these patients [see CONTRAINDICATIONS].
In patients with mild renal impairment (CrCl 51–80 mL/min), AMPYRA plasma levels may approach those seen at a dose of 15 mg twice daily, a dose that may be associated with an increased risk of seizures.
Concurrent Treatment with Other Forms of 4-Aminopyridine
AMPYRA should not be taken with other forms of 4-aminopyridine (4-AP, fampridine) since the active ingredient is the same. Patients should discontinue use of any product containing 4-aminopyridine prior to initiating treatment with AMPYRA in order to reduce the potential for dose-related adverse reactions.
AMPYRA can cause anaphylaxis and severe allergic reactions. Signs and symptoms have included respiratory compromise, urticaria, and angioedema of the throat and or tongue. Patients should be informed of the signs and symptoms of anaphylaxis and instructed to discontinue AMPYRA and seek immediate medical care should these signs and symptoms occur.
Urinary Tract Infections
Urinary tract infections (UTIs) were reported more frequently as adverse reactions in controlled studies in patients receiving AMPYRA 10 mg twice daily (12%) as compared to placebo (8%). UTIs in AMPYRA-treated patients should be evaluated and treated as clinically indicated.
Patient Counseling Information
See FDA-approved Patient Labeling
Risk of Seizures
Inform patients that AMPYRA can cause seizures, and that they must discontinue use of AMPYRA if they experience a seizure.
Instruct patients to take AMPYRA exactly as prescribed. Instruct patients not to take a double dose after they miss a dose, as this would increase their risk of seizure. Instruct patients not to take more than 2 tablets in a 24-hour period and to make sure that there is an approximate 12-hour interval between doses.
Advise patients to discontinue AMPYRA and seek medical care if they develop signs and symptoms of anaphylaxis.
Advise patients to store AMPYRA at 25°C (77°F), with excursions permitted to 15–30°C (59–86°F). Advise patients to safely throw away AMPYRA that is out of date or no longer needed.
Carcinogenesis, mutagenesis, impairment of fertility
Two year dietary carcinogenicity studies of dalfampridine were conducted in mice and rats. In mice, the doses tested (approximately 2, 12.5, and 80 mg/kg/day) were associated with plasma exposures (AUC) up to 11 times the plasma AUC in humans at the maximum recommended human dose (MRHD) of 20 mg/day. There was no evidence of drug-related carcinogenicity.
In rats, the doses tested (approximately 2, 6, and 18 mg/kg/day) were approximately 1, 3, and 9 times the MRHD on a body surface area (mg/m²) basis. There was a significant increase in uterine polyps at the highest dose tested.
Dalfampridine was negative in in vitro (bacterial reverse mutation, mouse lymphoma tk, chromosomal aberration) and in vivo (mouse bone marrow, rat erythrocyte micronucleus) genetic toxicology assays.
Impairment of Fertility
Oral administration of dalfampridine (doses of 1, 3, and 9 mg/kg/day) to male and female rats prior to and throughout mating, and continuing in females up to day 13 of gestation or day 21 of lactation resulted in no adverse effects on fertility. Reduced offspring viability and body weight were observed at 9 mg/kg/day. The mid dose (a no-effect dose) was similar to the MRHD on a mg/m² basis.
Use In Specific Populations
Pregnancy Category C
There are no adequate and well-controlled studies of AMPYRA in pregnant women. Administration of dalfampridine to animals during pregnancy and lactation resulted in decreased offspring viability and growth at doses similar to the maximum recommended human dose (MRHD) of 20 mg/day. AMPYRA should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
In developmental toxicity studies in rats and rabbits, dalfampridine was administered orally at doses up to 10 and 5 mg/kg/day, respectively, during the period of organogenesis. These doses are approximately 5 times the MRHD on a body surface area (mg/m²) basis. No evidence of developmental toxicity was found in either species at the highest doses tested, which were maternally toxic. Oral administration of dalfampridine (at doses of 1, 3, and 9 to 6 mg/kg/day; high dose reduced during the second week of dosing) to rats throughout the pregnancy and lactation periods resulted in decreased offspring survival and growth. The no-effect dose for pre- and postnatal developmental toxicity in rats (1 mg/kg) is approximately 0.5 times the MRHD on a mg/m² basis.
Labor and delivery
The effect of AMPYRA on labor and delivery in humans is unknown.
It is not known whether dalfampridine is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from dalfampridine, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Safety and effectiveness of AMPYRA in patients younger than 18 years of age have not been established.
Clinical studies of AMPYRA did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently than younger subjects. A population PK analysis showed that dalfampridine clearance modestly decreased with increasing age, but not sufficiently to necessitate a modification of dose with age. Other reported clinical experience has identified no differences in responses between the elderly and younger patients.
AMPYRA is known to be substantially excreted by the kidneys and the risk of adverse reactions, including seizures, is greater with increasing exposure of dalfampridine. Because elderly patients are more likely to have decreased renal function, it is particularly important to know the estimated creatinine clearance (CrCl) in these patients [see WARNINGS AND PRECAUTIONS].
Impaired Renal Function
Clearance of dalfampridine is decreased in patients with renal impairment and is significantly correlated with creatinine clearance (CrCl) [see CLINICAL PHARMACOLOGY, Special Populations]. AMPYRA is contraindicated in patients with moderate or severe renal impairment (CrCl ≤ 50 mL/min) [see CONTRAINDICATIONS]. The risk of seizures in patients with mild renal impairment (CrCl 51–80 mL/min) is unknown, but dalfampridine plasma levels in these patients may approach those seen at a dose of 15 mg twice daily, a dose that may be associated with an increased risk of seizures. If unknown, estimated creatinine clearance should be calculated prior to initiating treatment with AMPYRA [see DOSAGE AND ADMINISTRATION and WARNINGS AND PRECAUTIONS].
Last reviewed on RxList: 2/4/2013
This monograph has been modified to include the generic and brand name in many instances.
Additional Ampyra Information
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