amifampridine

Contraindicated in:

Hypersensitivity to amifampridine or another aminopyridine;
History of seizures;
End-stage renal disease (CCr <15 mL/min) (↑ risk of seizures).

Use Cautiously in:

Mild to moderate renal impairment (CCr 15–90 mL/min) (initiate with lowest dose and monitor closely);
Hepatic impairment (initiate with lowest dose and monitor closely);
NAT2 poor metabolizers (initiate with lowest dose and monitor closely);
OB: Safety not established in pregnancy;
Lactation: Use while breastfeeding only if potential maternal benefit justifies potential risk to infant;
Pedi: Children <6 yr (safety and effectiveness not established);
Geri: Consider age-related ↓ in renal function.

Adv. Reactions/Side Effects ⬆ ⬇

CV: hypertension, peripheral edema

Derm: erythema

EENT: cataracts

GI: abdominal pain, diarrhea, ↑liver enzymes, nausea, constipation, dyspepsia

GU: urinary tract infection

Metab: hypercholesterolemia

MS: back pain, extremity pain, muscle spasms, muscle weakness, ↑creatine kinase

Neuro: dizziness, headache, paresthesia, depression, insomnia, SEIZURES, weakness.

Resp: dyspnea

Misc: fever, HYPERSENSITIVITY REACTIONS (INCLUDING ANAPHYLAXIS)

Interactions ⬆ ⬇

Drug-drug:

Drugs that lower seizure threshold may ↑ risk of seizures.
Cholinesterase inhibitors (direct or indirect) may ↑ cholinergic effects.

Availability ⬆ ⬇

Route/Dosage ⬆ ⬇

PO (Adults and Children ≥6 yr and ≥45 kg): 15–30 mg/day in 3–5 divided doses; may ↑ by 5 mg/day every 3–4 days based on response and tolerability (not to exceed 20 mg/dose or 100 mg/day). NAT2 poor metabolizers: 15 mg/day in 3–5 divided doses; may ↑ by 5 mg/day every 3–4 days based on response and tolerability (not to exceed 20 mg/dose or 100 mg/day).
PO (Children ≥6 yr and <45 kg): 5–15 mg/day in 3–4 divided doses; may ↑ by 2.5 mg/day every 3–5 days (not to exceed 10 mg/dose or 50 mg/day). NAT2 poor metabolizers: 5 mg/day in 3–5 divided doses; may ↑ by 2.5 mg/day every 3–4 days based on response and tolerability (not to exceed 10 mg/dose or 50 mg/day).

Renal Impairment

PO (Adults and Children ≥6 yr and ≥45 kg): CCr 15–90 mL/min: 15 mg/day in 3–5 divided doses; may ↑ by 5 mg/day every 3–4 days based on response and tolerability (not to exceed 20 mg/dose or 100 mg/day).

Renal Impairment

(Children ≥6 yr and <45 kg): CCr 15–90 mL/min: 5 mg/day in 3–5 divided doses; may ↑ by 2.5 mg/day every 3–4 days based on response and tolerability (not to exceed 10 mg/dose or 50 mg/day).

Hepatic Impairment

(Adults and Children ≥6 yr and ≥45 kg): Mild, moderate, or severe hepatic impairment: 15 mg/day in 3–5 divided doses; may ↑ by 5 mg/day every 3–4 days based on response and tolerability (not to exceed 20 mg/dose or 100 mg/day).

Hepatic Impairment

(Children ≥6 yr and <45 kg): Mild, moderate, or severe hepatic impairment: 5 mg/day in 3–5 divided doses; may ↑ by 2.5 mg/day every 3–4 days based on response and tolerability (not to exceed 10 mg/dose or 50 mg/day).

US Brand Names ⬆ ⬇

Action ⬆ ⬇

Increases acetylcholine release in nerve terminals via potassium channel blockade.

Therapeutic effects:

Decreased progression of muscle weakness.

Classifications ⬆ ⬇

Therapeutic Classification: cholinergic muscle stimulants

Pharmacologic Classification: potassium channel blockers

Pharmacokinetics ⬆ ⬇

Absorption: Rapidly and well absorbed.

Distribution: Widely distributed to tissues.

Metabolism/Excretion: Extensively metabolized by N-acetyltransferase 2 (NAT2) to an inactive metabolite. Primarily eliminated in urine (as either unchanged drug or metabolite).

Half-Life: 1.8–2.5 hr.

Canadian Brand Names ⬆ ⬇

Time/Action Profile ⬆ ⬇

(plasma concentrations)

ROUTE	ONSET	PEAK	DURATION
PO	unknown	0.3–1 hr	unknown

Patient/Family Teaching ⬆ ⬇

Instruct patient to take medication as directed and follow dose escalation schedule. Advise patient to omit missed doses. Do not double doses; may increase risk of seizures. Do not change dose or stop medication without consulting health care professional.
Advise patient to notify health care professionals if seizures or signs and symptoms of hypersensitivity reaction (shortness of breath, trouble breathing, swelling of throat or tongue, hives) occur.
Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
Rep: Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding. Inform patient of pregnancy exposure registry that monitors pregnancy outcomes in women exposed to Firdapse during pregnancy. Clinicians are encouraged to enroll pregnant patients, or pregnant women may register themselves in the pregnancy registry (855-212-5856) or https://firdapsepregancystudy.com/.

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Indications ⬇

Contraind./Precautions ⬆ ⬇