THERAPEUTICS

Brands

• Ampyra, Fampyra, 4-aminopyridine

Generic?

• No

Class

• Potassium channel blocker

Commonly Prescribed for

(FDA approved in bold)

• To improve walking in patients with multiple sclerosis (MS)

• Spinal cord injury

How the Drug Works

• It is a broad-spectrum potassium channel antagonist that improves walking strength and speed in MS patients. Neurological improvement is probably associated with potassium channel inhibition that prolongs action potential and improves conduction in demyelinated axons. It may exert immunomodulatory effect on viable neurons through potassium channel blockade on microglia, macrophages, and lymphocytes that influence the autoimmune process in MS

How Long Until It Works

• Hours to days

If It Works

• Continue treatment. Monitor kidney function and any seizure activity

If It Doesn't Work

• Treat underlying MS with disease-modifying agents and symptomatic treatments

Best Augmenting Combos for Partial Response or Treatment-Resistance

• There is no other drug approved for improving walking in patients with MS. Does not affect MS progression

Tests

• Check kidney function before starting and periodically afterwards

ADVERSE EFFECTS (AEs)

How the Drug Causes AEs

• Potassium channel blockade

Notable AEs

• Asthenia, balance disorder, dizziness, headache, insomnia, nausea, urinary tract infection

Life-Threatening or Dangerous AEs

• Seizure (10 and 15 mg twice daily: 0.4% and 1.7% seizure incidence in clinical trial)

• Hypersensitivity reactions

Weight Gain

• Unusual

Sedation

• Unusual

What to Do About AEs

• Lower the dose or discontinue. Examine kidney function

Best Augmenting Agents to

Reduce AEs

• Most AEs cannot be reduced

DOSING AND USE

Usual Dosage Range

• 10 mg, every 12 hours

Dosage Forms

• Tablet, extended release: 10 mg

How to Dose

• 10 mg twice daily, 12 hours apart

• CrCl 51–80 mL/min: standard dose may result in plasma level similar to 15 mg twice daily with a potential risk of seizure