Dalfampridine is a potassium channel blocker used to improve walking in adult patients with multiple sclerosis (MS). It is a sustained-release tablet containing the active ingredient 4-aminopyridine. It works by improving conduction in demyelinated axons, thereby enhancing synaptic transmission and muscle function. It is specifically indicated for patients with walking disability (EDSS score 4-7).
Adult: 10 mg orally twice daily (approximately 12 hours apart). Do not exceed 10 mg in a 12-hour period.
Note: Tablet must be swallowed whole. Do not break, crush, or chew. Can be taken with or without food. If a dose is missed, skip it and take the next dose at the scheduled time. Do not take double or extra doses.
Dalfampridine is a broad-spectrum, voltage-dependent potassium channel blocker. In demyelinated axons, potassium channels are exposed, leading to potassium efflux that short-circuits the action potential, causing conduction failure. By blocking these channels, dalfampridine prolongs the duration of the action potential, increases calcium influx at the nerve terminal, and enhances the release of neurotransmitters. This improves synaptic transmission and conduction in demyelinated nerve fibers, leading to improved neurological function, particularly walking.
Pregnancy: Category C. Animal studies have shown adverse fetal effects. There are no adequate and well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus.
Driving: May cause dizziness, vertigo, and balance disorders. Patients should be cautioned about operating machinery or driving until they know how the medication affects them.
| Other Aminopyridines (e.g., 4-AP immediate-release) | Increased risk of seizures and adverse effects. | Major |
| Drugs that lower seizure threshold (e.g., Tramadol, Theophylline, Antipsychotics, Bupropion, certain Antibiotics) | Potentially increased risk of seizures. | Moderate to Major |
| Cimetidine | May reduce renal clearance of dalfampridine, increasing plasma levels and seizure risk. | Moderate |
| Probenecid | May inhibit renal tubular secretion of dalfampridine, increasing plasma levels. | Moderate |
| Octreotide | May reduce renal clearance of dalfampridine. | Moderate |