Overview
11 DESCRIPTION Dalfampridine is a potassium channel blocker, available in a 10 mg tablet strength. Each tablet contains 10 mg dalfampridine, formulated as an extended-release tablet for twice-daily oral administration. Dalfampridine is also known by its chemical name, 4-aminopyridine, with the following structure: Dalfampridine extended-release tablets are available in a 10 mg strength and are...
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of action The mechanism by which dalfampridine exerts its therapeutic effect has not been fully elucidated. Dalfampridine is a broad spectrum potassium channel blocker. In animal studies, dalfampridine has been shown to increase conduction of action potentials in demyelinated axons through inhibition of potassium channels. 12.2 Pharmacodynamics Dalfampridine extended-release tablets does not prolong the QTc interval and does not have a clinically important effect on QRS duration. 12.3 Pharmacokinetics Absorption and Distribution Orally administered dalfampridine is rapidly and completely absorbed from the gastrointestinal tract.
Indications
- 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 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 ).
Common Doses
- 10 mg
- 80 mL
- 15 mg
- 50 mL
Dosage
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.
Contraindications
- 4 CONTRAINDICATIONS The use of dalfampridine extended-release tablets are 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 extended-release tablets 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 extended-release tablets or 4-aminopyridine (4)
Side Effects
- 6 ADVERSE REACTIONS The following serious adverse reactions are described in more detail elsewhere in the labeling: •Seizures [see Warnings and Precautions ( 5.1 )] •Anaphylaxis [see Warnings and Precautions ( 5.4 )] The most common adverse events (incidence ≥2% and at a rate greater than the placebo rate) for dalfampridine extended-release tablets were urinary tract infection, insomnia, dizziness, headache, nausea, asthenia, back pain, balance disorder, multiple sclerosis relapse, paresthesia, nasopharyngitis, constipation, dyspepsia, and pharyngolaryngeal pain (6.1).
Interactions
- 7 DRUG INTERACTIONS OCT2 Inhibitors: Concomitant use may cause an increased exposure and potential risk of seizures ( 7.1 ) 7.1 OCT2 Inhibitors Concurrent treatment with OCT2 inhibitors, such as cimetidine, may cause increased exposure to dalfampridine [see Clinical Pharmacology ( 12.3 )] . Elevated levels of dalfampridine increase the risk of seizures [see Warnings and Precautions ( 5.1 , 5.2 )]. The potential benefits of taking OCT2 inhibitors concurrently with dalfampridine extended-release tablets should be considered against the risk of seizures in these patients. 7.