Dalfampridine (Fampyra) is a potassium channel blocker that improves neuronal conduction in demyelinated axons. It is used in patients with multiple sclerosis to improve their walking ability.

Dalfampridine (Fampyra)  Uses:

• It is used in patients with multiple sclerosis to improve mobility and walking.

Dalfampridine (Fampyra) Dose in Adults

Dalfampridine (Fampyra) Dose in the treatment of Multiple sclerosis:

• 10 mg orally twice daily.
• The maximum daily dose is 20 mg.
• Exceeding 20 mg may not confer additional benefits.
• Missed doses:
  • If a dose is missed, an extra dose or double dose should not be administered.

Use in Children:

Not indicated.

Pregnancy Risk Factor C

• Its use in pregnancy is not well-documented.

Use of Dalfampridine while breastfeeding

• It is unknown if the drug will be excreted into breastmilk.
• Experts recommend that you avoid breastfeeding while you are undergoing treatment, until more information is available.
• Because of possible adverse effects in breastfeeding infants, the manufacturer suggests that you either stop using the drug or breastfeed.

Dalfampridine (Fampyra) Dose in Kidney Disease:

Notice:The Cockcroft-Gault formula calculates creatinine clearance.

• The US labeling system:

  • Mild renal impairment (CrCl 51 - 80 mL/minute).
    • Although the manufacturer has not suggested any changes in the dosage, seizures could increase due to the reduced clearance.
  • Moderate-to-severe kidney impairment (CrCl = 50 mL/minute).
    • Contraindicated

• Canadian labeling

  • Mild to severe impairment (CrCl ==80 mL/minute).
    • Contraindicated

Dose in Liver disease:

• Adjustment in the dose is not required in patients with liver disease.
• The drug undergoes minimal metabolism and is primarily excreted in urine as unchanged.

Common Side Effects of Dalfampridine (Fampyra):

• Genitourinary:

  • Urinary tract infection

Less Common Side Effects of Dalfampridine (Fampyra):

• Central nervous system:

  • Insomnia
  • Dizziness
  • Headache
  • Equilibrium disturbance
  • Paresthesia

• Gastrointestinal:

  • Nausea
  • Constipation
  • Dyspepsia

• Neuromuscular & skeletal:

  • Weakness
  • Back pain
  • Acute exacerbations of multiple sclerosis

• Respiratory:

  • Nasopharyngitis
  • Pharyngolaryngeal pain

Contraindications to Dalfampridine (Fampyra):

• Allergy to dalfampridine or 4-aminopyridine or any other component of the formulation
• History of Fits;
• Moderate to severe renal impairment (CrCl >=50 mL/minute).

Additional contraindications to Canadian labeling

• Mild, moderate or severe renal impairment (CrCl >=80 mL/minute);
• Use of other forms or compounded 4-aminopyridines in conjunction with fampridine
• Use with medication that inhibits the organic cationtransporter 2 (e.g. , cimetidine, or quinidine)

Warnings and precautions

• Anaphylaxis

  • This drug can cause severe allergic reactions, including anaphylactic reactions.
  • Patients might present with symptoms such as urticaria, oropharyngeal, or laryngeal edema and angioedema (throat, tongue).
  • It is important to stop all treatment immediately and start the appropriate treatment such as Epinephrine.

• Seizures

  • Seizures are a common side effect of treatment, especially if you take higher doses.
  • Seizures can occur as soon as treatment is initiated or as late as weeks later.
  • Patients with a history of seizures are more likely to experience seizures.
  • Treatment must be stopped if the patient has seizures.
  • Patients who have had seizures in the past should not take this drug.
  • Before treatment can be initiated, it is important to assess the risk of developing seizures. Patients with a low risk of developing seizures should be treated cautiously.

• Infection of the urinary tract:

  • Clinical trials showed that the prevalence of urinary tract infections in patients with the placebo was higher than the placebo.
  • Patients with symptoms of the lower urinary tract must be evaluated.

• Renal impairment

  • Preexisting kidney disease patients are at greater risk for seizures and adverse drug reactions, especially neurological.
  • It is excreted primarily unchanged through the kidneys.
  • According to US drug labeling, it is contraindicated for moderate to severe renal impairment and mild, moderate and severe impairment according Canadian labeling.

Dalfampridine (fampridine): Drug Interaction

Note: Drug Interaction Categories:

• Risk Factor C: Monitor When Using Combination
• Risk Factor D: Consider Treatment Modification
• Risk Factor X: Avoid Concomitant Use

Monitoring parameters:

• Renal function should be monitored at baseline and at least annually thereafter
• Monitor EEG
• Monitor for the ability of the patient to walk.

How to administer Dalfampridine (Fampyra)?

• It may be administered with or without food.
• The drug should not be chewed, crushed, dissolved in liquids, or divided.

Mechanism of action of Dalfampridine (Fampyra):

• Motor function is improved by the drug acting as a non-specific potentiochannel blocker. 
• The potassium current blocker prolongs the action potential, delays repolarization, and improves nerve conduction in focally demyelinated Axons.
• A decrease in neuronal conduction can improve the neurological motor function through the strengthening of the skeletal muscle fiber twist activity.

Absorption:

• Rapid and complete

Protein binding:

• It is minimally bound to plasma proteins

Metabolism:

• The drug undergoes minimal metabolism.
• In vitro data suggests the drug is metabolized in the liver primarily via CYP2E1 to 3-hydroxy-4aminopyridine. It is then further conjugated to 3-hydroxy-4-aminopyridine sulfate. The metabolites are inactive.

Bioavailability:

• 96%

Half-life elimination:

• 5.2-6.5 hours;
• The half-life of the drug is prolonged in patients with severe renal impairment (about 3 times longer)

Time to peak plasma concentration:

• 3-4 hours

Excretion:

• Urine (96%; 90% of total dose as unchanged drug);
• feces (0.5%)

International Brand Names of Dalfampridine:

• Ampyra
• Fampyra
• Fampyra SR

Dalfampridine Brand Names in Pakistan:

No Brands Available in Pakistan.