Potassium channel blocker Pregnancy: Limited data in pregnant women; animal studies have shown reproductive toxicity. As a precautionary measure it is preferable to avoid the use of fampridine in pregnancy. Not recommended during breast-feeding (excretion in human milk unknown).

Fampridine

Brand names: Fampyra

Fampridine (prolonged-release 4-aminopyridine) is used to improve walking in adults with multiple sclerosis who have walking disability.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 10 mg (one 10 mg prolonged-release tablet)

Route: Oral

Frequency: Twice daily, taken 12 hours apart (one tablet in the morning and one in the evening)

Max: Should not be administered more frequently or at higher doses than the recommended 10 mg twice daily

Source: UK SPC for Fampyra 10 mg prolonged-release tablets (§4.2). Indication is improvement of walking in adults with multiple sclerosis; treatment is restricted to prescription and supervision by physicians experienced in the management of MS. Tablets should be taken WITHOUT food and swallowed whole — must not be divided, crushed, dissolved, sucked or chewed. Missed dose: follow the usual regimen; a double dose must not be taken. Starting/evaluating: initial prescription should be limited to two to four weeks of therapy, as clinical benefit is generally identified within two to four weeks; assess walking ability (e.g. Timed 25 Foot Walk or Twelve Item MS Walking Scale) within two to four weeks and discontinue if no improvement or if the patient reports no benefit. Re-evaluating: if walking ability declines, consider interrupting treatment, withdraw the medicine and reassess walking ability; discontinue if the patient no longer receives walking benefit. Elderly: check renal function before starting and monitor during treatment. Paediatric: safety and efficacy in children aged 0 to 18 years have not been established and no data are available (§4.2).

Dose adjustments

Renal

Contraindicated in moderate and severe renal impairment (creatinine clearance < 50 mL/min). Caution in mild renal impairment — higher plasma concentrations are associated with increased adverse reactions, particularly neurological. Determine renal function before treatment and monitor regularly in all patients, particularly the elderly (creatinine clearance may be estimated using the Cockcroft-Gault formula). No dose adjustment is required for hepatic impairment.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to fampridine or to any of the excipients
Concurrent treatment with other medicinal products containing fampridine (4-aminopyridine)
Prior history or current presentation of seizure
Moderate or severe renal impairment (creatinine clearance < 50 mL/min)
Concomitant use with inhibitors of Organic Cation Transporter 2 (OCT2), for example cimetidine

Side effects

Urinary tract infection (very common — approximately 12% of patients)
Dizziness and balance disorder (common; may increase risk of falls)
Headache and insomnia/anxiety (common)
Paraesthesia and tremor (common)
Nausea, vomiting, constipation, dyspepsia (common)
Seizure (uncommon) and hypersensitivity/anaphylaxis, angioedema (uncommon) — discontinue and do not restart

Interactions

Other fampridine (4-aminopyridine)-containing medicinal products — contraindicated (§4.3/§4.5)
OCT2 inhibitors, e.g. cimetidine — contraindicated; OCT2 is the transporter responsible for active renal secretion of fampridine (about 60% of elimination)
OCT2 substrates, e.g. carvedilol, propranolol, metformin — caution advised on concomitant use
Caution with any factors or medicines that may lower the seizure threshold (§4.4)

Clinical monograph

How it works

It is a potassium channel blocker that prolongs action potentials in demyelinated nerve fibres, improving conduction and neuromuscular transmission.

Prescribing in practice

It lowers the seizure threshold and is contraindicated in patients with a history of seizures, so screen carefully before starting.
It is renally excreted and contraindicated in renal impairment, so check renal function before and during treatment.
Treatment should be assessed early and stopped if there is no demonstrable improvement in walking, as benefit occurs only in a proportion of patients.

Monitoring

Assess renal function before and periodically during treatment, and evaluate walking ability to confirm the drug is providing benefit.

Counselling the patient

This medicine is intended to help your walking, and it will be stopped if it does not help you.
Take the tablets without food and swallow them whole; do not crush or halve them.
Tell us immediately if you have any seizure, blackout or unusual jerking.

Evidence & guidelines

Fampridine improves walking speed in a subset of people with multiple sclerosis in randomised controlled trials; response should be confirmed individually.

Reference: NICE TA833; SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways